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414 commits
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3822a7c409 |
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY/PoPQAKCRDdBJ7gKXxA jlvpAPsFECUBBl20qSue2zCYWnHC7Yk4q9ytTkPB/MMDrFEN9wD/SNKEm2UoK6/K DmxHkn0LAitGgJRS/W9w81yrgig9tAQ= =MlGs -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ... |
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b507808ebc |
mm: implement memory-deny-write-execute as a prctl
Patch series "mm: In-kernel support for memory-deny-write-execute (MDWE)", v2. The background to this is that systemd has a configuration option called MemoryDenyWriteExecute [2], implemented as a SECCOMP BPF filter. Its aim is to prevent a user task from inadvertently creating an executable mapping that is (or was) writeable. Since such BPF filter is stateless, it cannot detect mappings that were previously writeable but subsequently changed to read-only. Therefore the filter simply rejects any mprotect(PROT_EXEC). The side-effect is that on arm64 with BTI support (Branch Target Identification), the dynamic loader cannot change an ELF section from PROT_EXEC to PROT_EXEC|PROT_BTI using mprotect(). For libraries, it can resort to unmapping and re-mapping but for the main executable it does not have a file descriptor. The original bug report in the Red Hat bugzilla - [3] - and subsequent glibc workaround for libraries - [4]. This series adds in-kernel support for this feature as a prctl PR_SET_MDWE, that is inherited on fork(). The prctl denies PROT_WRITE | PROT_EXEC mappings. Like the systemd BPF filter it also denies adding PROT_EXEC to mappings. However unlike the BPF filter it only denies it if the mapping didn't previous have PROT_EXEC. This allows to PROT_EXEC -> PROT_EXEC | PROT_BTI with mprotect(), which is a problem with the BPF filter. This patch (of 2): The aim of such policy is to prevent a user task from creating an executable mapping that is also writeable. An example of mmap() returning -EACCESS if the policy is enabled: mmap(0, size, PROT_READ | PROT_WRITE | PROT_EXEC, flags, 0, 0); Similarly, mprotect() would return -EACCESS below: addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0); mprotect(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC); The BPF filter that systemd MDWE uses is stateless, and disallows mprotect() with PROT_EXEC completely. This new prctl allows PROT_EXEC to be enabled if it was already PROT_EXEC, which allows the following case: addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0); mprotect(addr, size, PROT_READ | PROT_EXEC | PROT_BTI); where PROT_BTI enables branch tracking identification on arm64. Link: https://lkml.kernel.org/r/20230119160344.54358-1-joey.gouly@arm.com Link: https://lkml.kernel.org/r/20230119160344.54358-2-joey.gouly@arm.com Signed-off-by: Joey Gouly <joey.gouly@arm.com> Co-developed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jeremy Linton <jeremy.linton@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Mark Brown <broonie@kernel.org> Cc: nd <nd@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Topi Miettinen <toiwoton@gmail.com> Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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7397906057 |
prlimit: do_prlimit needs to have a speculation check
do_prlimit() adds the user-controlled resource value to a pointer that will subsequently be dereferenced. In order to help prevent this codepath from being used as a spectre "gadget" a barrier needs to be added after checking the range. Reported-by: Jordy Zomer <jordyzomer@google.com> Tested-by: Jordy Zomer <jordyzomer@google.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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8adc0486f3 |
Random number generator updates for Linux 6.1-rc1.
-----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEq5lC5tSkz8NBJiCnSfxwEqXeA64FAmM++NMACgkQSfxwEqXe A65f3w//eRwdaZV5eX3m9eb3CsNnnut2dDKNG+HrImd+z+96CbpBCsyZN2p5uDMw pPownat8Ejv6P6E0ztOAyCsFDnS0Tf2YjdVOZ9txif5zIwqoM8TYbmHlmm7JhACc hDoblbICTf/bmSURWQOCdkayPhqIyV61pF5hwXXQuCAMoanHzDWbH1yxMmBMCQYJ P6fA0r2BYniC90o/C0HvToeIw7tTGxBm2Lki/S9cWOFCzPBwQytBbE7AD4rBP8+Y ryHdcpKaXLF9C1zSlYfyLBbBGR3Oe+DBLl081q3LkTjnnoPbLEtJE1B644K5FiOJ ySkeHZoMeGB2fisoEJAaEf1GjA1I6f1fcmTlY57XbR/iU3gfQE6+06CwVJBUoqtx Q71FMU+AMoc1ZfDVQB8NC+RdifV1qRhzVPrawhCPPfx8ngR8yKekh9RYwp0xpGPL RoAqswoOwOW20BalNxRipLji1URcZGH1d3QgkjdIwxvodyPsiGg74LJ9xBYWccfv jBS6vNEGgWYUtMA/20W0HowSizA89Rl9REBd7M8q+eLOhJ/AsUgzuJ9noODBe6OV PO4NDWXwaud64gDHtPhomah/14zej53yomlC/qJ9cJN4uPo6J3u9phqcaOWHjgPX AKYRGWxCgnwpf7g6v4S/35kU+OEs9fS+oDKUzUY8s7lhNM4qCK0= =KGwF -----END PGP SIGNATURE----- Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random Pull random number generator updates from Jason Donenfeld: - Huawei reported that when they updated their kernel from 4.4 to something much newer, some userspace code they had broke, the culprit being the accidental removal of O_NONBLOCK from /dev/random way back in 5.6. It's been gone for over 2 years now and this is the first we've heard of it, but userspace breakage is userspace breakage, so O_NONBLOCK is now back. - Use randomness from hardware RNGs much more often during early boot, at the same interval that crng reseeds are done, from Dominik. - A semantic change in hardware RNG throttling, so that the hwrng framework can properly feed random.c with randomness from hardware RNGs that aren't specifically marked as creditable. A related patch coming to you via Herbert's hwrng tree depends on this one, not to compile, but just to function properly, so you may want to merge this PULL before that one. - A fix to clamp credited bits from the interrupts pool to the size of the pool sample. This is mainly just a theoretical fix, as it'd be pretty hard to exceed it in practice. - Oracle reported that InfiniBand TCP latency regressed by around 10-15% after a change a few cycles ago made at the request of the RT folks, in which we hoisted a somewhat rare operation (1 in 1024 times) out of the hard IRQ handler and into a workqueue, a pretty common and boring pattern. It turns out, though, that scheduling a worker from there has overhead of its own, whereas scheduling a timer on that same CPU for the next jiffy amortizes better and doesn't incur the same overhead. I also eliminated a cache miss by moving the work_struct (and subsequently, the timer_list) to below a critical cache line, so that the more critical members that are accessed on every hard IRQ aren't split between two cache lines. - The boot-time initialization of the RNG has been split into two approximate phases: what we can accomplish before timekeeping is possible and what we can accomplish after. This winds up being useful so that we can use RDRAND to seed the RNG before CONFIG_SLAB_FREELIST_RANDOM=y systems initialize slabs, in addition to other early uses of randomness. The effect is that systems with RDRAND (or a bootloader seed) will never see any warnings at all when setting CONFIG_WARN_ALL_UNSEEDED_RANDOM=y. And kfence benefits from getting a better seed of its own. - Small systems without much entropy sometimes wind up putting some truncated serial number read from flash into hostname, so contribute utsname changes to the RNG, without crediting. - Add smaller batches to serve requests for smaller integers, and make use of them when people ask for random numbers bounded by a given compile-time constant. This has positive effects all over the tree, most notably in networking and kfence. - The original jitter algorithm intended (I believe) to schedule the timer for the next jiffy, not the next-next jiffy, yet it used mod_timer(jiffies + 1), which will fire on the next-next jiffy, instead of what I believe was intended, mod_timer(jiffies), which will fire on the next jiffy. So fix that. - Fix a comment typo, from William. * tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: random: clear new batches when bringing new CPUs online random: fix typos in get_random_bytes() comment random: schedule jitter credit for next jiffy, not in two jiffies prandom: make use of smaller types in prandom_u32_max random: add 8-bit and 16-bit batches utsname: contribute changes to RNG random: use init_utsname() instead of utsname() kfence: use better stack hash seed random: split initialization into early step and later step random: use expired timer rather than wq for mixing fast pool random: avoid reading two cache lines on irq randomness random: clamp credited irq bits to maximum mixed random: throttle hwrng writes if no entropy is credited random: use hwgenerator randomness more frequently at early boot random: restore O_NONBLOCK support |
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493ffd6605 |
ucounts: Split rlimit and ucount values and max values
After the ucount rlimit code was merged a bunch of small but siginificant bugs were found and fixed. At the time it was realized that part of the problem was that while the ucount rlimits were very similar to the oridinary ucounts (in being nested counts with limits) the semantics were slightly different and the code would be less error prone if there was less sharing. This is the long awaited cleanup that should hopefully keep things more comprehensible and less error prone for whoever needs to touch that code next. Alexey Gladkov (1): ucounts: Split rlimit and ucount values and max values fs/exec.c | 2 +- fs/proc/array.c | 2 +- include/linux/user_namespace.h | 35 ++++++++++++++++++++++------------- kernel/fork.c | 12 ++++++------ kernel/sys.c | 2 +- kernel/ucount.c | 34 +++++++++++++++------------------- kernel/user_namespace.c | 10 +++++----- 7 files changed, 51 insertions(+), 46 deletions(-) -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEgjlraLDcwBA2B+6cC/v6Eiajj0AFAmM7U4cACgkQC/v6Eiaj j0AbRA//RVrGJ9n5iYyHM7WgeoTlFbaupEyLTq5dEpkOMD9CEB4OpMymGA/VXbeX cjgF5dqykfrdpYBwJdosl1fgq15ZFe9ChKhPGQkI5CGlwyRYTl2kq+FrZLC790s8 c4TN3fKO1DyQPn5+UNzlBgLP8ofiUqeScZJDGa+LeMlUIv1OFS3m05jHuG/uzl6b bbbdcn61tFKOFCapbE72hWusEQssPOAN+dSY1/lwKO05WOKR0N2CR0EHyZhW2Owd GIQ27Zh5ed/9xRNlxa8VIa+JDfuATbPeoWcvRmiWSEoAxKtPBUf8lwcltlHBUcKK 72MH+KU9AaIZ1prq9ng4xEaM+vXiSSNspYB8siwph7au1gWx1Yu2yYVavEPeFB9o C0JaD7kTh6Mhk6xdPhnmFUHFOLLGC5LdnBcIwwoMb1jlwP4QJRVucbjpqaOptoiE SeWhRRKUBwpcQdztQZCR+X0h1paHRJJXplHFmeEGcMviGWntgKUaxXJQ4BJrnRTO pagn7h181KVF7u9Toh0IWzrd322mXNqmcgwhzE/S9pa5EJMQHt7qYkDzQCgEwoap JmIld9tKkv/0fYMOHordjMb1OY37feI7FyDAuZuLP1ZWYgKhOq0LrD5x8PzKmoyM 6oKAOfXZUVT/Pnw21nEzAtHsazV3mLRpW+gLLiLSiWoSaYT4x14= =kjVh -----END PGP SIGNATURE----- Merge tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull ucounts update from Eric Biederman: "Split rlimit and ucount values and max values After the ucount rlimit code was merged a bunch of small but siginificant bugs were found and fixed. At the time it was realized that part of the problem was that while the ucount rlimits were very similar to the oridinary ucounts (in being nested counts with limits) the semantics were slightly different and the code would be less error prone if there was less sharing. This is the long awaited cleanup that should hopefully keep things more comprehensible and less error prone for whoever needs to touch that code next" * tag 'ucount-rlimits-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ucounts: Split rlimit and ucount values and max values |
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37608ba315 |
utsname: contribute changes to RNG
On some small machines with little entropy, a quasi-unique hostname is sometimes a relevant factor. I've seen, for example, 8 character alpha-numeric serial numbers. In addition, the time at which the hostname is set is usually a decent measurement of how long early boot took. So, call add_device_randomness() on new hostnames, which feeds its arguments to the RNG in addition to a fresh cycle counter. Low cost hooks like this never hurt and can only ever help, and since this costs basically nothing for an operation that is never a fast path, this is an overall easy win. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> |
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de399236e2 |
ucounts: Split rlimit and ucount values and max values
Since the semantics of maximum rlimit values are different, it would be better not to mix ucount and rlimit values. This will prevent the error of using inc_count/dec_ucount for rlimit parameters. This patch also renames the functions to emphasize the lack of connection between rlimit and ucount. v3: - Fix BUG:KASAN:use-after-free_in_dec_ucount. v2: - Fix the array-index-out-of-bounds that was found by the lkp project. Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Link: https://lkml.kernel.org/r/20220518171730.l65lmnnjtnxnftpq@example.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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9e4ab6c891 |
arm64/sme: Implement vector length configuration prctl()s
As for SVE provide a prctl() interface which allows processes to configure their SME vector length. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20220419112247.711548-12-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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18c91bb2d8 |
prlimit: do not grab the tasklist_lock
Unnecessarily grabbing the tasklist_lock can be a scalability bottleneck for workloads that also must grab the tasklist_lock for waiting, killing, and cloning. The tasklist_lock was grabbed to protect tsk->sighand from disappearing (becoming NULL). tsk->signal was already protected by holding a reference to tsk. update_rlimit_cpu() assumed tsk->sighand != NULL. With this commit, it attempts to lock_task_sighand(). However, this means that update_rlimit_cpu() can fail. This only happens when a task is exiting. Note that during exec, sighand may *change*, but it will not be NULL. Prior to this commit, the do_prlimit() ensured that update_rlimit_cpu() would not fail by read locking the tasklist_lock and checking tsk->sighand != NULL. If update_rlimit_cpu() fails, there may be other tasks that are not exiting that share tsk->signal. However, the group_leader is the last task to be released, so if we cannot update_rlimit_cpu(group_leader), then the entire process is exiting. The only other caller of update_rlimit_cpu() is selinux_bprm_committing_creds(). It has tsk == current, so update_rlimit_cpu() cannot fail (current->sighand cannot disappear until current exits). This change resulted in a 14% speedup on a microbenchmark where parents kill and wait on their children, and children getpriority, setpriority, and getrlimit. Signed-off-by: Barret Rhoden <brho@google.com> Link: https://lkml.kernel.org/r/20220106172041.522167-4-brho@google.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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c57bef0287 |
prlimit: make do_prlimit() static
There are no other callers in the kernel. Fixed up a comment format and whitespace issue when moving do_prlimit() higher in sys.c. Signed-off-by: Barret Rhoden <brho@google.com> Link: https://lkml.kernel.org/r/20220106172041.522167-3-brho@google.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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5c26f6ac94 |
mm: refactor vm_area_struct::anon_vma_name usage code
Avoid mixing strings and their anon_vma_name referenced pointers by using struct anon_vma_name whenever possible. This simplifies the code and allows easier sharing of anon_vma_name structures when they represent the same name. [surenb@google.com: fix comment] Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Colin Cross <ccross@google.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Alexey Gladkov <legion@kernel.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Chris Hyser <chris.hyser@oracle.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Peter Collingbourne <pcc@google.com> Cc: Xiaofeng Cao <caoxiaofeng@yulong.com> Cc: David Hildenbrand <david@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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c923a8e7ed |
ucounts: Move RLIMIT_NPROC handling after set_user
During set*id() which cred->ucounts to charge the the current process
to is not known until after set_cred_ucounts. So move the
RLIMIT_NPROC checking into a new helper flag_nproc_exceeded and call
flag_nproc_exceeded after set_cred_ucounts.
This is very much an arbitrary subset of the places where we currently
change the RLIMIT_NPROC accounting, designed to preserve the existing
logic.
Fixing the existing logic will be the subject of another series of
changes.
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220216155832.680775-4-ebiederm@xmission.com
Fixes:
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c16bdeb5a3 |
rlimit: Fix RLIMIT_NPROC enforcement failure caused by capability calls in set_user
Solar Designer <solar@openwall.com> wrote: > I'm not aware of anyone actually running into this issue and reporting > it. The systems that I personally know use suexec along with rlimits > still run older/distro kernels, so would not yet be affected. > > So my mention was based on my understanding of how suexec works, and > code review. Specifically, Apache httpd has the setting RLimitNPROC, > which makes it set RLIMIT_NPROC: > > https://httpd.apache.org/docs/2.4/mod/core.html#rlimitnproc > > The above documentation for it includes: > > "This applies to processes forked from Apache httpd children servicing > requests, not the Apache httpd children themselves. This includes CGI > scripts and SSI exec commands, but not any processes forked from the > Apache httpd parent, such as piped logs." > > In code, there are: > > ./modules/generators/mod_cgid.c: ( (cgid_req.limits.limit_nproc_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC, > ./modules/generators/mod_cgi.c: ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC, > ./modules/filters/mod_ext_filter.c: rv = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC, conf->limit_nproc); > > For example, in mod_cgi.c this is in run_cgi_child(). > > I think this means an httpd child sets RLIMIT_NPROC shortly before it > execs suexec, which is a SUID root program. suexec then switches to the > target user and execs the CGI script. > > Before |
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f4484d138b |
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: "55 patches. Subsystems affected by this patch series: percpu, procfs, sysctl, misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2, hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits) lib: remove redundant assignment to variable ret ubsan: remove CONFIG_UBSAN_OBJECT_SIZE kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB btrfs: use generic Kconfig option for 256kB page size limit arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB configs: introduce debug.config for CI-like setup delayacct: track delays from memory compact Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact delayacct: cleanup flags in struct task_delay_info and functions use it delayacct: fix incomplete disable operation when switch enable to disable delayacct: support swapin delay accounting for swapping without blkio panic: remove oops_id panic: use error_report_end tracepoint on warnings fs/adfs: remove unneeded variable make code cleaner FAT: use io_schedule_timeout() instead of congestion_wait() hfsplus: use struct_group_attr() for memcpy() region nilfs2: remove redundant pointer sbufs fs/binfmt_elf: use PT_LOAD p_align values for static PIE const_structs.checkpatch: add frequently used ops structs ... |
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7f8ca0edfe |
kernel/sys.c: only take tasklist_lock for get/setpriority(PRIO_PGRP)
PRIO_PGRP needs the tasklist_lock mainly to serialize vs setpgid(2), to protect against any concurrent change_pid(PIDTYPE_PGID) that can move the task from one hlist to another while iterating. However, the remaining can only rely only on RCU: PRIO_PROCESS only does the task lookup and never iterates over tasklist and we already have an rcu-aware stable pointer. PRIO_USER is already racy vs setuid(2) so with creds being rcu protected, we can end up seeing stale data. When removing the tasklist_lock there can be a race with (i) fork but this is benign as the child's nice is inherited and the new task is not observable by the user yet either, hence the return semantics do not differ. And (ii) a race with exit, which is a small window and can cause us to miss a task which was removed from the list and it had the highest nice. Similarly change the buggy do_each_thread/while_each_thread combo in PRIO_USER for the rcu-safe for_each_process_thread flavor, which doesn't make use of next_thread/p->thread_group. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/20211210182250.43734-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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9a10064f56 |
mm: add a field to store names for private anonymous memory
In many userspace applications, and especially in VM based applications like Android uses heavily, there are multiple different allocators in use. At a minimum there is libc malloc and the stack, and in many cases there are libc malloc, the stack, direct syscalls to mmap anonymous memory, and multiple VM heaps (one for small objects, one for big objects, etc.). Each of these layers usually has its own tools to inspect its usage; malloc by compiling a debug version, the VM through heap inspection tools, and for direct syscalls there is usually no way to track them. On Android we heavily use a set of tools that use an extended version of the logic covered in Documentation/vm/pagemap.txt to walk all pages mapped in userspace and slice their usage by process, shared (COW) vs. unique mappings, backing, etc. This can account for real physical memory usage even in cases like fork without exec (which Android uses heavily to share as many private COW pages as possible between processes), Kernel SamePage Merging, and clean zero pages. It produces a measurement of the pages that only exist in that process (USS, for unique), and a measurement of the physical memory usage of that process with the cost of shared pages being evenly split between processes that share them (PSS). If all anonymous memory is indistinguishable then figuring out the real physical memory usage (PSS) of each heap requires either a pagemap walking tool that can understand the heap debugging of every layer, or for every layer's heap debugging tools to implement the pagemap walking logic, in which case it is hard to get a consistent view of memory across the whole system. Tracking the information in userspace leads to all sorts of problems. It either needs to be stored inside the process, which means every process has to have an API to export its current heap information upon request, or it has to be stored externally in a filesystem that somebody needs to clean up on crashes. It needs to be readable while the process is still running, so it has to have some sort of synchronization with every layer of userspace. Efficiently tracking the ranges requires reimplementing something like the kernel vma trees, and linking to it from every layer of userspace. It requires more memory, more syscalls, more runtime cost, and more complexity to separately track regions that the kernel is already tracking. This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a userspace-provided name for anonymous vmas. The names of named anonymous vmas are shown in /proc/pid/maps and /proc/pid/smaps as [anon:<name>]. Userspace can set the name for a region of memory by calling prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name) Setting the name to NULL clears it. The name length limit is 80 bytes including NUL-terminator and is checked to contain only printable ascii characters (including space), except '[',']','\','$' and '`'. Ascii strings are being used to have a descriptive identifiers for vmas, which can be understood by the users reading /proc/pid/maps or /proc/pid/smaps. Names can be standardized for a given system and they can include some variable parts such as the name of the allocator or a library, tid of the thread using it, etc. The name is stored in a pointer in the shared union in vm_area_struct that points to a null terminated string. Anonymous vmas with the same name (equivalent strings) and are otherwise mergeable will be merged. The name pointers are not shared between vmas even if they contain the same name. The name pointer is stored in a union with fields that are only used on file-backed mappings, so it does not increase memory usage. CONFIG_ANON_VMA_NAME kernel configuration is introduced to enable this feature. It keeps the feature disabled by default to prevent any additional memory overhead and to avoid confusing procfs parsers on systems which are not ready to support named anonymous vmas. The patch is based on the original patch developed by Colin Cross, more specifically on its latest version [1] posted upstream by Sumit Semwal. It used a userspace pointer to store vma names. In that design, name pointers could be shared between vmas. However during the last upstreaming attempt, Kees Cook raised concerns [2] about this approach and suggested to copy the name into kernel memory space, perform validity checks [3] and store as a string referenced from vm_area_struct. One big concern is about fork() performance which would need to strdup anonymous vma names. Dave Hansen suggested experimenting with worst-case scenario of forking a process with 64k vmas having longest possible names [4]. I ran this experiment on an ARM64 Android device and recorded a worst-case regression of almost 40% when forking such a process. This regression is addressed in the followup patch which replaces the pointer to a name with a refcounted structure that allows sharing the name pointer between vmas of the same name. Instead of duplicating the string during fork() or when splitting a vma it increments the refcount. [1] https://lore.kernel.org/linux-mm/20200901161459.11772-4-sumit.semwal@linaro.org/ [2] https://lore.kernel.org/linux-mm/202009031031.D32EF57ED@keescook/ [3] https://lore.kernel.org/linux-mm/202009031022.3834F692@keescook/ [4] https://lore.kernel.org/linux-mm/5d0358ab-8c47-2f5f-8e43-23b89d6a8e95@intel.com/ Changes for prctl(2) manual page (in the options section): PR_SET_VMA Sets an attribute specified in arg2 for virtual memory areas starting from the address specified in arg3 and spanning the size specified in arg4. arg5 specifies the value of the attribute to be set. Note that assigning an attribute to a virtual memory area might prevent it from being merged with adjacent virtual memory areas due to the difference in that attribute's value. Currently, arg2 must be one of: PR_SET_VMA_ANON_NAME Set a name for anonymous virtual memory areas. arg5 should be a pointer to a null-terminated string containing the name. The name length including null byte cannot exceed 80 bytes. If arg5 is NULL, the name of the appropriate anonymous virtual memory areas will be reset. The name can contain only printable ascii characters (including space), except '[',']','\','$' and '`'. This feature is available only if the kernel is built with the CONFIG_ANON_VMA_NAME option enabled. [surenb@google.com: docs: proc.rst: /proc/PID/maps: fix malformed table] Link: https://lkml.kernel.org/r/20211123185928.2513763-1-surenb@google.com [surenb: rebased over v5.15-rc6, replaced userpointer with a kernel copy, added input sanitization and CONFIG_ANON_VMA_NAME config. The bulk of the work here was done by Colin Cross, therefore, with his permission, keeping him as the author] Link: https://lkml.kernel.org/r/20211019215511.3771969-2-surenb@google.com Signed-off-by: Colin Cross <ccross@google.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Glauber <jan.glauber@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rob Landley <rob@landley.net> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Shaohua Li <shli@fusionio.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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2d338201d5 |
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
"147 patches, based on
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e1fbbd0731 |
prctl: allow to setup brk for et_dyn executables
Keno Fischer reported that when a binray loaded via ld-linux-x the
prctl(PR_SET_MM_MAP) doesn't allow to setup brk value because it lays
before mm:end_data.
For example a test program shows
| # ~/t
|
| start_code 401000
| end_code 401a15
| start_stack 7ffce4577dd0
| start_data 403e10
| end_data 40408c
| start_brk b5b000
| sbrk(0) b5b000
and when executed via ld-linux
| # /lib64/ld-linux-x86-64.so.2 ~/t
|
| start_code 7fc25b0a4000
| end_code 7fc25b0c4524
| start_stack 7fffcc6b2400
| start_data 7fc25b0ce4c0
| end_data 7fc25b0cff98
| start_brk 55555710c000
| sbrk(0) 55555710c000
This of course prevent criu from restoring such programs. Looking into
how kernel operates with brk/start_brk inside brk() syscall I don't see
any problem if we allow to setup brk/start_brk without checking for
end_data. Even if someone pass some weird address here on a purpose then
the worst possible result will be an unexpected unmapping of existing vma
(own vma, since prctl works with the callers memory) but test for
RLIMIT_DATA is still valid and a user won't be able to gain more memory in
case of expanding VMAs via new values shipped with prctl call.
Link: https://lkml.kernel.org/r/20210121221207.GB2174@grain
Fixes:
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49624efa65 |
Merge tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux
Pull MAP_DENYWRITE removal from David Hildenbrand: "Remove all in-tree usage of MAP_DENYWRITE from the kernel and remove VM_DENYWRITE. There are some (minor) user-visible changes: - We no longer deny write access to shared libaries loaded via legacy uselib(); this behavior matches modern user space e.g. dlopen(). - We no longer deny write access to the elf interpreter after exec completed, treating it just like shared libraries (which it often is). - We always deny write access to the file linked via /proc/pid/exe: sys_prctl(PR_SET_MM_MAP/EXE_FILE) will fail if write access to the file cannot be denied, and write access to the file will remain denied until the link is effectivel gone (exec, termination, sys_prctl(PR_SET_MM_MAP/EXE_FILE)) -- just as if exec'ing the file. Cross-compiled for a bunch of architectures (alpha, microblaze, i386, s390x, ...) and verified via ltp that especially the relevant tests (i.e., creat07 and execve04) continue working as expected" * tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux: fs: update documentation of get_write_access() and friends mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff() mm: remove VM_DENYWRITE binfmt: remove in-tree usage of MAP_DENYWRITE kernel/fork: always deny write access to current MM exe_file kernel/fork: factor out replacing the current MM exe_file binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib() |
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35d7bdc860 |
kernel/fork: factor out replacing the current MM exe_file
Let's factor the main logic out into replace_mm_exe_file(), such that all mm->exe_file logic is contained in kernel/fork.c. While at it, perform some simple cleanups that are possible now that we're simplifying the individual functions. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: David Hildenbrand <david@redhat.com> |
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2863643fb8
|
set_user: add capability check when rlimit(RLIMIT_NPROC) exceeds
in copy_process(): non root users but with capability CAP_SYS_RESOURCE or CAP_SYS_ADMIN will clean PF_NPROC_EXCEEDED flag even rlimit(RLIMIT_NPROC) exceeds. Add the same capability check logic here. Align the permission checks in copy_process() and set_user(). In copy_process() CAP_SYS_RESOURCE or CAP_SYS_ADMIN capable users will be able to circumvent and clear the PF_NPROC_EXCEEDED flag whereas they aren't able to the same in set_user(). There's no obvious logic to this and trying to unearth the reason in the thread didn't go anywhere. The gist seems to be that this code wants to make sure that a program can't successfully exec if it has gone through a set*id() transition while exceeding its RLIMIT_NPROC. A capable but non-INIT_USER caller getting PF_NPROC_EXCEEDED set during a set*id() transition wouldn't be able to exec right away if they still exceed their RLIMIT_NPROC at the time of exec. So their exec would fail in fs/exec.c: if ((current->flags & PF_NPROC_EXCEEDED) && is_ucounts_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { retval = -EAGAIN; goto out_ret; } However, if the caller were to fork() right after the set*id() transition but before the exec while still exceeding their RLIMIT_NPROC then they would get PF_NPROC_EXCEEDED cleared (while the child would inherit it): retval = -EAGAIN; if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { if (p->real_cred->user != INIT_USER && !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) goto bad_fork_free; } current->flags &= ~PF_NPROC_EXCEEDED; which means a subsequent exec by the capable caller would now succeed even though they could still exceed their RLIMIT_NPROC limit. This seems inconsistent. Allow a CAP_SYS_ADMIN or CAP_SYS_RESOURCE capable user to avoid PF_NPROC_EXCEEDED as they already can in copy_process(). Cc: peterz@infradead.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, Ran Xiaokai <ran.xiaokai@zte.com.cn>, , , Link: https://lore.kernel.org/r/20210728072629.530435-1-ran.xiaokai@zte.com.cn Cc: Neil Brown <neilb@suse.de> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: James Morris <jamorris@linux.microsoft.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> |
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c54b245d01 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace rlimit handling update from Eric Biederman: "This is the work mainly by Alexey Gladkov to limit rlimits to the rlimits of the user that created a user namespace, and to allow users to have stricter limits on the resources created within a user namespace." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: cred: add missing return error code when set_cred_ucounts() failed ucounts: Silence warning in dec_rlimit_ucounts ucounts: Set ucount_max to the largest positive value the type can hold kselftests: Add test to check for rlimit changes in different user namespaces Reimplement RLIMIT_MEMLOCK on top of ucounts Reimplement RLIMIT_SIGPENDING on top of ucounts Reimplement RLIMIT_MSGQUEUE on top of ucounts Reimplement RLIMIT_NPROC on top of ucounts Use atomic_t for ucounts reference counting Add a reference to ucounts for each cred Increase size of ucounts to atomic_long_t |
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7ac592aa35 |
sched: prctl() core-scheduling interface
This patch provides support for setting and copying core scheduling 'task cookies' between threads (PID), processes (TGID), and process groups (PGID). The value of core scheduling isn't that tasks don't share a core, 'nosmt' can do that. The value lies in exploiting all the sharing opportunities that exist to recover possible lost performance and that requires a degree of flexibility in the API. From a security perspective (and there are others), the thread, process and process group distinction is an existent hierarchal categorization of tasks that reflects many of the security concerns about 'data sharing'. For example, protecting against cache-snooping by a thread that can just read the memory directly isn't all that useful. With this in mind, subcommands to CREATE/SHARE (TO/FROM) provide a mechanism to create and share cookies. CREATE/SHARE_TO specify a target pid with enum pidtype used to specify the scope of the targeted tasks. For example, PIDTYPE_TGID will share the cookie with the process and all of it's threads as typically desired in a security scenario. API: prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, tgtpid, pidtype, &cookie) prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, tgtpid, pidtype, NULL) prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, tgtpid, pidtype, NULL) prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, srcpid, pidtype, NULL) where 'tgtpid/srcpid == 0' implies the current process and pidtype is kernel enum pid_type {PIDTYPE_PID, PIDTYPE_TGID, PIDTYPE_PGID, ...}. For return values, EINVAL, ENOMEM are what they say. ESRCH means the tgtpid/srcpid was not found. EPERM indicates lack of PTRACE permission access to tgtpid/srcpid. ENODEV indicates your machines lacks SMT. [peterz: complete rewrite] Signed-off-by: Chris Hyser <chris.hyser@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Don Hiatt <dhiatt@digitalocean.com> Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com> Tested-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210422123309.039845339@infradead.org |
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5afe69c2cc |
kernel/sys.c: fix typo
change 'infite' to 'infinite' change 'concurent' to 'concurrent' change 'memvers' to 'members' change 'decendants' to 'descendants' change 'argumets' to 'arguments' Link: https://lkml.kernel.org/r/20210316112904.10661-1-cxfcosmos@gmail.com Signed-off-by: Xiaofeng Cao <caoxiaofeng@yulong.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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21d1c5e386 |
Reimplement RLIMIT_NPROC on top of ucounts
The rlimit counter is tied to uid in the user_namespace. This allows rlimit values to be specified in userns even if they are already globally exceeded by the user. However, the value of the previous user_namespaces cannot be exceeded. To illustrate the impact of rlimits, let's say there is a program that does not fork. Some service-A wants to run this program as user X in multiple containers. Since the program never fork the service wants to set RLIMIT_NPROC=1. service-A \- program (uid=1000, container1, rlimit_nproc=1) \- program (uid=1000, container2, rlimit_nproc=1) The service-A sets RLIMIT_NPROC=1 and runs the program in container1. When the service-A tries to run a program with RLIMIT_NPROC=1 in container2 it fails since user X already has one running process. We cannot use existing inc_ucounts / dec_ucounts because they do not allow us to exceed the maximum for the counter. Some rlimits can be overlimited by root or if the user has the appropriate capability. Changelog v11: * Change inc_rlimit_ucounts() which now returns top value of ucounts. * Drop inc_rlimit_ucounts_and_test() because the return code of inc_rlimit_ucounts() can be checked. Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/c5286a8aa16d2d698c222f7532f3d735c82bc6bc.1619094428.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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905ae01c4a |
Add a reference to ucounts for each cred
For RLIMIT_NPROC and some other rlimits the user_struct that holds the global limit is kept alive for the lifetime of a process by keeping it in struct cred. Adding a pointer to ucounts in the struct cred will allow to track RLIMIT_NPROC not only for user in the system, but for user in the user_namespace. Updating ucounts may require memory allocation which may fail. So, we cannot change cred.ucounts in the commit_creds() because this function cannot fail and it should always return 0. For this reason, we modify cred.ucounts before calling the commit_creds(). Changelog v6: * Fix null-ptr-deref in is_ucounts_overlimit() detected by trinity. This error was caused by the fact that cred_alloc_blank() left the ucounts pointer empty. Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/b37aaef28d8b9b0d757e07ba6dd27281bbe39259.1619094428.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> |
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201698626f |
arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
This change introduces a prctl that allows the user program to control which PAC keys are enabled in a particular task. The main reason why this is useful is to enable a userspace ABI that uses PAC to sign and authenticate function pointers and other pointers exposed outside of the function, while still allowing binaries conforming to the ABI to interoperate with legacy binaries that do not sign or authenticate pointers. The idea is that a dynamic loader or early startup code would issue this prctl very early after establishing that a process may load legacy binaries, but before executing any PAC instructions. This change adds a small amount of overhead to kernel entry and exit due to additional required instruction sequences. On a DragonBoard 845c (Cortex-A75) with the powersave governor, the overhead of similar instruction sequences was measured as 4.9ns when simulating the common case where IA is left enabled, or 43.7ns when simulating the uncommon case where IA is disabled. These numbers can be seen as the worst case scenario, since in more realistic scenarios a better performing governor would be used and a newer chip would be used that would support PAC unlike Cortex-A75 and would be expected to be faster than Cortex-A75. On an Apple M1 under a hypervisor, the overhead of the entry/exit instruction sequences introduced by this patch was measured as 0.3ns in the case where IA is left enabled, and 33.0ns in the case where IA is disabled. Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Link: https://linux-review.googlesource.com/id/Ibc41a5e6a76b275efbaa126b31119dc197b927a5 Link: https://lore.kernel.org/r/d6609065f8f40397a4124654eb68c9f490b4d477.1616123271.git.pcc@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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c995f12ad8 |
prctl: fix PR_SET_MM_AUXV kernel stack leak
Doing a prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1); will copy 1 byte from userspace to (quite big) on-stack array and then stash everything to mm->saved_auxv. AT_NULL terminator will be inserted at the very end. /proc/*/auxv handler will find that AT_NULL terminator and copy original stack contents to userspace. This devious scheme requires CAP_SYS_RESOURCE. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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6fbd6cf85a |
Kbuild updates for v5.12
- Fix false-positive build warnings for ARCH=ia64 builds - Optimize dictionary size for module compression with xz - Check the compiler and linker versions in Kconfig - Fix misuse of extra-y - Support DWARF v5 debug info - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x exceeded the limit - Add generic syscall{tbl,hdr}.sh for cleanups across arches - Minor cleanups of genksyms - Minor cleanups of Kconfig -----BEGIN PGP SIGNATURE----- iQJJBAABCgAzFiEEbmPs18K1szRHjPqEPYsBB53g2wYFAmA3zhgVHG1hc2FoaXJv eUBrZXJuZWwub3JnAAoJED2LAQed4NsG0C4P/A5hUNFdkYI+EffAWZiHn69t0S8j M1GQkZildKu/yOfm6hp3mNwgHmYgw0aAuch1htkJuv+5rXRtoK77yw0xKbUqNHyO VqkJWQPVUXJbWIDiu332NaETHbFTWCnPZKGmzcbVOBHbYsXUJPp17gROQ9ke0fQN Ae6OV5WINhoS8UnjESWb3qOO87MdQTZ+9mP+NMnVh4kV1SUeMAXLFwFll66KZTkj GXB330N3p9L0wQVljhXpQ/YPOd76wJNPhJWJ9+hKLFbWsedovzlHb+duprh1z1xe 7LLaq9dEbXxe1Uz0qmK76lupXxilYMyUupTW9HIYtIsY8br8DIoBOG0bn46LVnuL /m+UQNfUFCYYePT7iZQNNc1DISQJrxme3bjq0PJzZTDukNnHJVahnj9x4RoNaF8j Dc+JME0r2i8Ccp28vgmaRgzvSsb8Xtw5icwRdwzIpyt1ubs/+tkd/GSaGzQo30Q8 m8y1WOjovHNX7OGnOaOWBGoQAX/2k/VHeAediMsPqWUoOxwsLHYxG/4KtgwbJ5vc gu/Fyk1GRDklZPpLdYFVvz8TGnqSDogJgF+7WolJ6YvPGAUIDAfd5Ky2sWayddlm wchc3sKDVyh3lov23h0WQVTvLO9xl+NZ6THxoAGdYeQ0DUu5OxwH8qje/UpWuo1a DchhNN+g5pa6n56Z =sLxb -----END PGP SIGNATURE----- Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Fix false-positive build warnings for ARCH=ia64 builds - Optimize dictionary size for module compression with xz - Check the compiler and linker versions in Kconfig - Fix misuse of extra-y - Support DWARF v5 debug info - Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x exceeded the limit - Add generic syscall{tbl,hdr}.sh for cleanups across arches - Minor cleanups of genksyms - Minor cleanups of Kconfig * tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits) initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD kbuild: remove deprecated 'always' and 'hostprogs-y/m' kbuild: parse C= and M= before changing the working directory kbuild: reuse this-makefile to define abs_srctree kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig kconfig: omit --oldaskconfig option for 'make config' kconfig: fix 'invalid option' for help option kconfig: remove dead code in conf_askvalue() kconfig: clean up nested if-conditionals in check_conf() kconfig: Remove duplicate call to sym_get_string_value() Makefile: Remove # characters from compiler string Makefile: reuse CC_VERSION_TEXT kbuild: check the minimum linker version in Kconfig kbuild: remove ld-version macro scripts: add generic syscallhdr.sh scripts: add generic syscalltbl.sh arch: syscalls: remove $(srctree)/ prefix from syscall tables arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work gen_compile_commands: prune some directories kbuild: simplify access to the kernel's version ... |
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7d6beb71da |
idmapped-mounts-v5.12
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
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88a686728b |
kbuild: simplify access to the kernel's version
Instead of storing the version in a single integer and having various kernel (and userspace) code how it's constructed, export individual (major, patchlevel, sublevel) components and simplify kernel code that uses it. This should also make it easier on userspace. Signed-off-by: Sasha Levin <sashal@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> |
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be65de6b03 |
fs: Remove dcookies support
The dcookies stuff was only used by the kernel's old oprofile code. Now that oprofile's support is removed from the kernel, there is no need for dcookies as well. Remove it. Suggested-by: Christoph Hellwig <hch@infradead.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Robert Richter <rric@kernel.org> Acked-by: William Cohen <wcohen@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Thomas Gleixner <tglx@linutronix.de> |
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02f92b3868
|
fs: add file and path permissions helpers
Add two simple helpers to check permissions on a file and path respectively and convert over some callers. It simplifies quite a few codepaths and also reduces the churn in later patches quite a bit. Christoph also correctly points out that this makes codepaths (e.g. ioctls) way easier to follow that would otherwise have to do more complex argument passing than necessary. Link: https://lore.kernel.org/r/20210121131959.646623-4-christian.brauner@ubuntu.com Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> |
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1446e1df9e |
kernel: Implement selective syscall userspace redirection
Introduce a mechanism to quickly disable/enable syscall handling for a specific process and redirect to userspace via SIGSYS. This is useful for processes with parts that require syscall redirection and parts that don't, but who need to perform this boundary crossing really fast, without paying the cost of a system call to reconfigure syscall handling on each boundary transition. This is particularly important for Windows games running over Wine. The proposed interface looks like this: prctl(PR_SET_SYSCALL_USER_DISPATCH, <op>, <off>, <length>, [selector]) The range [<offset>,<offset>+<length>) is a part of the process memory map that is allowed to by-pass the redirection code and dispatch syscalls directly, such that in fast paths a process doesn't need to disable the trap nor the kernel has to check the selector. This is essential to return from SIGSYS to a blocked area without triggering another SIGSYS from rt_sigreturn. selector is an optional pointer to a char-sized userspace memory region that has a key switch for the mechanism. This key switch is set to either PR_SYS_DISPATCH_ON, PR_SYS_DISPATCH_OFF to enable and disable the redirection without calling the kernel. The feature is meant to be set per-thread and it is disabled on fork/clone/execv. Internally, this doesn't add overhead to the syscall hot path, and it requires very little per-architecture support. I avoided using seccomp, even though it duplicates some functionality, due to previous feedback that maybe it shouldn't mix with seccomp since it is not a security mechanism. And obviously, this should never be considered a security mechanism, since any part of the program can by-pass it by using the syscall dispatcher. For the sysinfo benchmark, which measures the overhead added to executing a native syscall that doesn't require interception, the overhead using only the direct dispatcher region to issue syscalls is pretty much irrelevant. The overhead of using the selector goes around 40ns for a native (unredirected) syscall in my system, and it is (as expected) dominated by the supervisor-mode user-address access. In fact, with SMAP off, the overhead is consistently less than 5ns on my test box. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201127193238.821364-4-krisman@collabora.com |
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986b9eacb2 |
kernel/sys.c: fix prototype of prctl_get_tid_address()
tid_addr is not a "pointer to (pointer to int in userspace)"; it is in fact a "pointer to (pointer to int in userspace) in userspace". So sparse rightfully complains about passing a kernel pointer to put_user(). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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81ecf91eab |
SafeSetID changes for v5.10
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15ec0fcff6 |
kernel/sys.c: replace do_brk with do_brk_flags in comment of prctl_set_mm_map()
Replace do_brk with do_brk_flags in comment of prctl_set_mm_map(), since
do_brk was removed in following commit.
Fixes:
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111767c1d8 |
LSM: Signal to SafeSetID when setting group IDs
For SafeSetID to properly gate set*gid() calls, it needs to know whether ns_capable() is being called from within a sys_set*gid() function or is being called from elsewhere in the kernel. This allows SafeSetID to deny CAP_SETGID to restricted groups when they are attempting to use the capability for code paths other than updating GIDs (e.g. setting up userns GID mappings). This is the identical approach to what is currently done for CAP_SETUID. NOTE: We also add signaling to SafeSetID from the setgroups() syscall, as we have future plans to restrict a process' ability to set supplementary groups in addition to what is added in this series for restricting setting of the primary group. Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org> |
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df561f6688 |
treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> |
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227175b2c9 |
prctl: exe link permission error changed from -EINVAL to -EPERM
This brings consistency with the rest of the prctl() syscall where -EPERM is returned when failing a capability check. Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com> Signed-off-by: Adrian Reber <areber@redhat.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Link: https://lore.kernel.org/r/20200719100418.2112740-7-areber@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> |
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ebd6de6812 |
prctl: Allow local CAP_CHECKPOINT_RESTORE to change /proc/self/exe
Originally, only a local CAP_SYS_ADMIN could change the exe link, making it difficult for doing checkpoint/restore without CAP_SYS_ADMIN. This commit adds CAP_CHECKPOINT_RESTORE in addition to CAP_SYS_ADMIN for permitting changing the exe link. The following describes the history of the /proc/self/exe permission checks as it may be difficult to understand what decisions lead to this point. * [1] May 2012: This commit introduces the ability of changing /proc/self/exe if the user is CAP_SYS_RESOURCE capable. In the related discussion [2], no clear thread model is presented for what could happen if the /proc/self/exe changes multiple times, or why would the admin be at the mercy of userspace. * [3] Oct 2014: This commit introduces a new API to change /proc/self/exe. The permission no longer checks for CAP_SYS_RESOURCE, but instead checks if the current user is root (uid=0) in its local namespace. In the related discussion [4] it is said that "Controlling exe_fd without privileges may turn out to be dangerous. At least things like tomoyo examine it for making policy decisions (see tomoyo_manager())." * [5] Dec 2016: This commit removes the restriction to change /proc/self/exe at most once. The related discussion [6] informs that the audit subsystem relies on the exe symlink, presumably audit_log_d_path_exe() in kernel/audit.c. * [7] May 2017: This commit changed the check from uid==0 to local CAP_SYS_ADMIN. No discussion. * [8] July 2020: A PoC to spoof any program's /proc/self/exe via ptrace is demonstrated Overall, the concrete points that were made to retain capability checks around changing the exe symlink is that tomoyo_manager() and audit_log_d_path_exe() uses the exe_file path. Christian Brauner said that relying on /proc/<pid>/exe being immutable (or guarded by caps) in a sake of security is a bit misleading. It can only be used as a hint without any guarantees of what code is being executed once execve() returns to userspace. Christian suggested that in the future, we could call audit_log() or similar to inform the admin of all exe link changes, instead of attempting to provide security guarantees via permission checks. However, this proposed change requires the understanding of the security implications in the tomoyo/audit subsystems. [1] |
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4a87b197c1 |
Add additional LSM hooks for SafeSetID
SafeSetID is capable of making allow/deny decisions for set*uid calls on a system, and we want to add similar functionality for set*gid calls. The work to do that is not yet complete, so probably won't make it in for v5.8, but we are looking to get this simple patch in for v5.8 since we have it ready. We are planning on the rest of the work for extending the SafeSetID LSM being merged during the v5.9 merge window. This patch was sent to the security mailing list and there were no objections. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEgvWslnM+qUy+sgVg5n2WYw6TPBAFAl7mZCoACgkQ5n2WYw6T PBAk1RAAl8t3/m3lELf8qIir4OAd4nK0kc4e+7W8WkznX2ljUl2IetlNxDCBmEXr T5qoW6uPsr6kl5AKnbl9Ii7WpW/halsslpKSUNQCs6zbecoVdxekJ8ISW7xHuboZ SvS1bqm+t++PM0c0nWSFEr7eXYmPH8OGbCqu6/+nnbxPZf2rJX03e5LnHkEFDFnZ 0D/rsKgzMt01pdBJQXeoKk79etHO5MjuAkkYVEKJKCR1fM16lk7ECaCp0KJv1Mmx I88VncbLvI+um4t82d1Z8qDr2iLgogjJrMZC4WKfxDTmlmxox2Fz9ZJo+8sIWk6k T3a95x0s/mYCO4gWtpCVICt9+71Z3ie9T2iaI+CIe/kJvI/ysb+7LSkF+PD33bdz 0yv6Y9+VMRdzb3pW69R28IoP4wdYQOJRomsY49z6ypH0RgBWcBvyE6e4v+WJGRNK E164Imevf6rrZeqJ0kGSBS1nL9WmQHMaXabAwxg1jK1KRZD+YZj3EKC9S/+PAkaT 1qXUgvGuXHGjQrwU0hclQjgc6BAudWfAGdfrVr7IWwNKJmjgBf6C35my/azrkOg9 wHCEpUWVmZZLIZLM69/6QXdmMA+iR+rPz5qlVnWhWTfjRYJUXM455Zk+aNo+Qnwi +saCcdU+9xqreLeDIoYoebcV/ctHeW0XCQi/+ebjexXVlyeSfYs= =I+0L -----END PGP SIGNATURE----- Merge tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux Pull SafeSetID update from Micah Morton: "Add additional LSM hooks for SafeSetID SafeSetID is capable of making allow/deny decisions for set*uid calls on a system, and we want to add similar functionality for set*gid calls. The work to do that is not yet complete, so probably won't make it in for v5.8, but we are looking to get this simple patch in for v5.8 since we have it ready. We are planning on the rest of the work for extending the SafeSetID LSM being merged during the v5.9 merge window" * tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux: security: Add LSM hooks to set*gid syscalls |
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39030e1351 |
security: Add LSM hooks to set*gid syscalls
The SafeSetID LSM uses the security_task_fix_setuid hook to filter set*uid() syscalls according to its configured security policy. In preparation for adding analagous support in the LSM for set*gid() syscalls, we add the requisite hook here. Tested by putting print statements in the security_task_fix_setgid hook and seeing them get hit during kernel boot. Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org> |
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c1e8d7c6a7 |
mmap locking API: convert mmap_sem comments
Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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d8ed45c5dc |
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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94709049fb |
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton: "A few little subsystems and a start of a lot of MM patches. Subsystems affected by this patch series: squashfs, ocfs2, parisc, vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup, swap, memcg, pagemap, memory-failure, vmalloc, kasan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits) kasan: move kasan_report() into report.c mm/mm_init.c: report kasan-tag information stored in page->flags ubsan: entirely disable alignment checks under UBSAN_TRAP kasan: fix clang compilation warning due to stack protector x86/mm: remove vmalloc faulting mm: remove vmalloc_sync_(un)mappings() x86/mm/32: implement arch_sync_kernel_mappings() x86/mm/64: implement arch_sync_kernel_mappings() mm/ioremap: track which page-table levels were modified mm/vmalloc: track which page-table levels were modified mm: add functions to track page directory modifications s390: use __vmalloc_node in stack_alloc powerpc: use __vmalloc_node in alloc_vm_stack arm64: use __vmalloc_node in arch_alloc_vmap_stack mm: remove vmalloc_user_node_flags mm: switch the test_vmalloc module to use __vmalloc_node mm: remove __vmalloc_node_flags_caller mm: remove both instances of __vmalloc_node_flags mm: remove the prot argument to __vmalloc_node mm: remove the pgprot argument to __vmalloc ... |
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a37b0715dd |
mm/writeback: replace PF_LESS_THROTTLE with PF_LOCAL_THROTTLE
PF_LESS_THROTTLE exists for loop-back nfsd (and a similar need in the loop block driver and callers of prctl(PR_SET_IO_FLUSHER)), where a daemon needs to write to one bdi (the final bdi) in order to free up writes queued to another bdi (the client bdi). The daemon sets PF_LESS_THROTTLE and gets a larger allowance of dirty pages, so that it can still dirty pages after other processses have been throttled. The purpose of this is to avoid deadlock that happen when the PF_LESS_THROTTLE process must write for any dirty pages to be freed, but it is being thottled and cannot write. This approach was designed when all threads were blocked equally, independently on which device they were writing to, or how fast it was. Since that time the writeback algorithm has changed substantially with different threads getting different allowances based on non-trivial heuristics. This means the simple "add 25%" heuristic is no longer reliable. The important issue is not that the daemon needs a *larger* dirty page allowance, but that it needs a *private* dirty page allowance, so that dirty pages for the "client" bdi that it is helping to clear (the bdi for an NFS filesystem or loop block device etc) do not affect the throttling of the daemon writing to the "final" bdi. This patch changes the heuristic so that the task is not throttled when the bdi it is writing to has a dirty page count below below (or equal to) the free-run threshold for that bdi. This ensures it will always be able to have some pages in flight, and so will not deadlock. In a steady-state, it is expected that PF_LOCAL_THROTTLE tasks might still be throttled by global threshold, but that is acceptable as it is only the deadlock state that is interesting for this flag. This approach of "only throttle when target bdi is busy" is consistent with the other use of PF_LESS_THROTTLE in current_may_throttle(), were it causes attention to be focussed only on the target bdi. So this patch - renames PF_LESS_THROTTLE to PF_LOCAL_THROTTLE, - removes the 25% bonus that that flag gives, and - If PF_LOCAL_THROTTLE is set, don't delay at all unless the global and the local free-run thresholds are exceeded. Note that previously realtime threads were treated the same as PF_LESS_THROTTLE threads. This patch does *not* change the behvaiour for real-time threads, so it is now different from the behaviour of nfsd and loop tasks. I don't know what is wanted for realtime. [akpm@linux-foundation.org: coding style fixes] Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Chuck Lever <chuck.lever@oracle.com> [nfsd] Cc: Christoph Hellwig <hch@lst.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Link: http://lkml.kernel.org/r/87ftbf7gs3.fsf@notabene.neil.brown.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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ce5155c4f8 |
compat sysinfo(2): don't bother with field-by-field copyout
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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ecc421e05b |
sys/sysinfo: Respect boottime inside time namespace
The sysinfo() syscall includes uptime in seconds but has no correction for time namespaces which makes it inconsistent with the /proc/uptime inside of a time namespace. Add the missing time namespace adjustment call. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dmitry Safonov <dima@arista.com> Link: https://lkml.kernel.org/r/20200303150638.7329-1-chrubis@suse.cz |
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8d19f1c8e1
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prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim
There are several storage drivers like dm-multipath, iscsi, tcmu-runner, amd nbd that have userspace components that can run in the IO path. For example, iscsi and nbd's userspace deamons may need to recreate a socket and/or send IO on it, and dm-multipath's daemon multipathd may need to send SG IO or read/write IO to figure out the state of paths and re-set them up. In the kernel these drivers have access to GFP_NOIO/GFP_NOFS and the memalloc_*_save/restore functions to control the allocation behavior, but for userspace we would end up hitting an allocation that ended up writing data back to the same device we are trying to allocate for. The device is then in a state of deadlock, because to execute IO the device needs to allocate memory, but to allocate memory the memory layers want execute IO to the device. Here is an example with nbd using a local userspace daemon that performs network IO to a remote server. We are using XFS on top of the nbd device, but it can happen with any FS or other modules layered on top of the nbd device that can write out data to free memory. Here a nbd daemon helper thread, msgr-worker-1, is performing a write/sendmsg on a socket to execute a request. This kicks off a reclaim operation which results in a WRITE to the nbd device and the nbd thread calling back into the mm layer. [ 1626.609191] msgr-worker-1 D 0 1026 1 0x00004000 [ 1626.609193] Call Trace: [ 1626.609195] ? __schedule+0x29b/0x630 [ 1626.609197] ? wait_for_completion+0xe0/0x170 [ 1626.609198] schedule+0x30/0xb0 [ 1626.609200] schedule_timeout+0x1f6/0x2f0 [ 1626.609202] ? blk_finish_plug+0x21/0x2e [ 1626.609204] ? _xfs_buf_ioapply+0x2e6/0x410 [ 1626.609206] ? wait_for_completion+0xe0/0x170 [ 1626.609208] wait_for_completion+0x108/0x170 [ 1626.609210] ? wake_up_q+0x70/0x70 [ 1626.609212] ? __xfs_buf_submit+0x12e/0x250 [ 1626.609214] ? xfs_bwrite+0x25/0x60 [ 1626.609215] xfs_buf_iowait+0x22/0xf0 [ 1626.609218] __xfs_buf_submit+0x12e/0x250 [ 1626.609220] xfs_bwrite+0x25/0x60 [ 1626.609222] xfs_reclaim_inode+0x2e8/0x310 [ 1626.609224] xfs_reclaim_inodes_ag+0x1b6/0x300 [ 1626.609227] xfs_reclaim_inodes_nr+0x31/0x40 [ 1626.609228] super_cache_scan+0x152/0x1a0 [ 1626.609231] do_shrink_slab+0x12c/0x2d0 [ 1626.609233] shrink_slab+0x9c/0x2a0 [ 1626.609235] shrink_node+0xd7/0x470 [ 1626.609237] do_try_to_free_pages+0xbf/0x380 [ 1626.609240] try_to_free_pages+0xd9/0x1f0 [ 1626.609245] __alloc_pages_slowpath+0x3a4/0xd30 [ 1626.609251] ? ___slab_alloc+0x238/0x560 [ 1626.609254] __alloc_pages_nodemask+0x30c/0x350 [ 1626.609259] skb_page_frag_refill+0x97/0xd0 [ 1626.609274] sk_page_frag_refill+0x1d/0x80 [ 1626.609279] tcp_sendmsg_locked+0x2bb/0xdd0 [ 1626.609304] tcp_sendmsg+0x27/0x40 [ 1626.609307] sock_sendmsg+0x54/0x60 [ 1626.609308] ___sys_sendmsg+0x29f/0x320 [ 1626.609313] ? sock_poll+0x66/0xb0 [ 1626.609318] ? ep_item_poll.isra.15+0x40/0xc0 [ 1626.609320] ? ep_send_events_proc+0xe6/0x230 [ 1626.609322] ? hrtimer_try_to_cancel+0x54/0xf0 [ 1626.609324] ? ep_read_events_proc+0xc0/0xc0 [ 1626.609326] ? _raw_write_unlock_irq+0xa/0x20 [ 1626.609327] ? ep_scan_ready_list.constprop.19+0x218/0x230 [ 1626.609329] ? __hrtimer_init+0xb0/0xb0 [ 1626.609331] ? _raw_spin_unlock_irq+0xa/0x20 [ 1626.609334] ? ep_poll+0x26c/0x4a0 [ 1626.609337] ? tcp_tsq_write.part.54+0xa0/0xa0 [ 1626.609339] ? release_sock+0x43/0x90 [ 1626.609341] ? _raw_spin_unlock_bh+0xa/0x20 [ 1626.609342] __sys_sendmsg+0x47/0x80 [ 1626.609347] do_syscall_64+0x5f/0x1c0 [ 1626.609349] ? prepare_exit_to_usermode+0x75/0xa0 [ 1626.609351] entry_SYSCALL_64_after_hwframe+0x44/0xa9 This patch adds a new prctl command that daemons can use after they have done their initial setup, and before they start to do allocations that are in the IO path. It sets the PF_MEMALLOC_NOIO and PF_LESS_THROTTLE flags so both userspace block and FS threads can use it to avoid the allocation recursion and try to prevent from being throttled while writing out data to free up memory. Signed-off-by: Mike Christie <mchristi@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Masato Suzuki <masato.suzuki@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Link: https://lore.kernel.org/r/20191112001900.9206-1-mchristi@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> |