linux-stable/arch
Andy Lutomirski 6365b842aa x86/syscalls: Split the x32 syscalls into their own table
For unfortunate historical reasons, the x32 syscalls and the x86_64
syscalls are not all numbered the same.  As an example, ioctl() is nr 16 on
x86_64 but 514 on x32.

This has potentially nasty consequences, since it means that there are two
valid RAX values to do ioctl(2) and two invalid RAX values.  The valid
values are 16 (i.e. ioctl(2) using the x86_64 ABI) and (514 | 0x40000000)
(i.e. ioctl(2) using the x32 ABI).

The invalid values are 514 and (16 | 0x40000000).  514 will enter the
"COMPAT_SYSCALL_DEFINE3(ioctl, ...)" entry point with in_compat_syscall()
and in_x32_syscall() returning false, whereas (16 | 0x40000000) will enter
the native entry point with in_compat_syscall() and in_x32_syscall()
returning true.  Both are bogus, and both will exercise code paths in the
kernel and in any running seccomp filters that really ought to be
unreachable.

Splitting out the x32 syscalls into their own tables, allows both bogus
invocations to return -ENOSYS.  I've checked glibc, musl, and Bionic, and
all of them appear to call syscalls with their correct numbers, so this
change should have no effect on them.

There is an added benefit going forward: new syscalls that need special
handling on x32 can share the same number on x32 and x86_64.  This means
that the special syscall range 512-547 can be treated as a legacy wart
instead of something that may need to be extended in the future.

Also add a selftest to verify the new behavior.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/208024256b764312598f014ebfb0a42472c19354.1562185330.git.luto@kernel.org
2019-07-22 10:31:23 +02:00
..
alpha Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
arc Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
arm Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
arm64 Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
c6x Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2019-07-10 21:42:03 -07:00
csky arch/csky patches for 5.3-rc1 2019-07-19 12:15:33 -07:00
h8300 h8300 update for 5.3 2019-07-17 09:36:38 -07:00
hexagon hexagon: switch to generic version of pte allocation 2019-07-21 09:53:00 -07:00
ia64 Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
m68k arch: mark syscall number 435 reserved for clone3 2019-07-15 00:39:33 +02:00
microblaze clone3-v5.3 2019-07-11 10:09:44 -07:00
mips This round of clk driver and framework updates is heavy on the driver update 2019-07-17 10:07:48 -07:00
nds32 nds32: fix asm/syscall.h 2019-07-16 19:23:24 -07:00
nios2 nios2 update for v5.3-rc1 2019-07-12 15:38:05 -07:00
openrisc dma-mapping updates for Linux 5.3 2019-07-12 15:13:55 -07:00
parisc Merge branch 'parisc-5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2019-07-18 12:23:45 -07:00
powerpc mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of pfns 2019-07-18 17:08:06 -07:00
riscv Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
s390 dma-mapping fixes for 5.3-rc1 2019-07-20 12:09:52 -07:00
sh mm/memory_hotplug: allow arch_remove_memory() without CONFIG_MEMORY_HOTREMOVE 2019-07-18 17:08:06 -07:00
sparc Kbuild updates for v5.3 (2nd) 2019-07-20 09:34:55 -07:00
um This pull request contains the following changes for UML: 2019-07-14 17:17:34 -07:00
unicore32 Kconfig updates for v5.3 2019-07-12 16:06:27 -07:00
x86 x86/syscalls: Split the x32 syscalls into their own table 2019-07-22 10:31:23 +02:00
xtensa Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
.gitignore
Kconfig Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-20 10:33:44 -07:00