Commit Graph

480 Commits

Author SHA1 Message Date
Linus Torvalds 6ef192f225 Modules updates for v4.11
Summary of modules changes for the 4.11 merge window:
 
 - A few small code cleanups
 
 - Add modules git tree url to MAINTAINERS
 
 Signed-off-by: Jessica Yu <jeyu@redhat.com>
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Merge tag 'modules-for-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull modules updates from Jessica Yu:
 "Summary of modules changes for the 4.11 merge window:

   - A few small code cleanups

   - Add modules git tree url to MAINTAINERS"

* tag 'modules-for-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  MAINTAINERS: add tree for modules
  module: fix memory leak on early load_module() failures
  module: Optimize search_module_extables()
  modules: mark __inittest/__exittest as __maybe_unused
  livepatch/module: print notice of TAINT_LIVEPATCH
  module: Drop redundant declaration of struct module
2017-02-22 17:08:33 -08:00
Linus Torvalds 7bb033829e This renames the (now inaccurate) CONFIG_DEBUG_RODATA and related config
CONFIG_SET_MODULE_RONX to the more sensible CONFIG_STRICT_KERNEL_RWX and
 CONFIG_STRICT_MODULE_RWX.
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Merge tag 'rodata-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull rodata updates from Kees Cook:
 "This renames the (now inaccurate) DEBUG_RODATA and related
  SET_MODULE_RONX configs to the more sensible STRICT_KERNEL_RWX and
  STRICT_MODULE_RWX"

* tag 'rodata-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  arch: Rename CONFIG_DEBUG_RODATA and CONFIG_DEBUG_MODULE_RONX
  arch: Move CONFIG_DEBUG_RODATA and CONFIG_SET_MODULE_RONX to be common
2017-02-21 17:56:45 -08:00
Linus Torvalds 6d1c42d9b9 Final extable.h related changes.
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Merge tag 'extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull exception table module split from Paul Gortmaker:
 "Final extable.h related changes.

  This completes the separation of exception table content from the
  module.h header file. This is achieved with the final commit that
  removes the one line back compatible change that sourced extable.h
  into the module.h file.

  The commits are unchanged since January, with the exception of a
  couple Acks that came in for the last two commits a bit later. The
  changes have been in linux-next for quite some time[1] and have got
  widespread arch coverage via toolchains I have and also from
  additional ones the kbuild bot has.

  Maintaners of the various arch were Cc'd during the postings to
  lkml[2] and informed that the intention was to take the remaining arch
  specific changes and lump them together with the final two non-arch
  specific changes and submit for this merge window.

  The ia64 diffstat stands out and probably warrants a mention. In an
  earlier review, Al Viro made a valid comment that the original header
  separation of content left something to be desired, and that it get
  fixed as a part of this change, hence the larger diffstat"

* tag 'extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (21 commits)
  module.h: remove extable.h include now users have migrated
  core: migrate exception table users off module.h and onto extable.h
  cris: migrate exception table users off module.h and onto extable.h
  hexagon: migrate exception table users off module.h and onto extable.h
  microblaze: migrate exception table users off module.h and onto extable.h
  unicore32: migrate exception table users off module.h and onto extable.h
  score: migrate exception table users off module.h and onto extable.h
  metag: migrate exception table users off module.h and onto extable.h
  arc: migrate exception table users off module.h and onto extable.h
  nios2: migrate exception table users off module.h and onto extable.h
  sparc: migrate exception table users onto extable.h
  openrisc: migrate exception table users off module.h and onto extable.h
  frv: migrate exception table users off module.h and onto extable.h
  sh: migrate exception table users off module.h and onto extable.h
  xtensa: migrate exception table users off module.h and onto extable.h
  mn10300: migrate exception table users off module.h and onto extable.h
  alpha: migrate exception table users off module.h and onto extable.h
  arm: migrate exception table users off module.h and onto extable.h
  m32r: migrate exception table users off module.h and onto extable.h
  ia64: ensure exception table search users include extable.h
  ...
2017-02-21 14:28:55 -08:00
Linus Torvalds b8989bccd6 Merge branch 'stable-4.11' of git://git.infradead.org/users/pcmoore/audit
Pull audit updates from Paul Moore:
 "The audit changes for v4.11 are relatively small compared to what we
  did for v4.10, both in terms of size and impact.

   - two patches from Steve tweak the formatting for some of the audit
     records to make them more consistent with other audit records.

   - three patches from Richard record the name of a module on module
     load, fix the logging of sockaddr information when using
     socketcall() on 32-bit systems, and add the ability to reset
     audit's lost record counter.

   - my lone patch just fixes an annoying style nit that I was reminded
     about by one of Richard's patches.

  All these patches pass our test suite"

* 'stable-4.11' of git://git.infradead.org/users/pcmoore/audit:
  audit: remove unnecessary curly braces from switch/case statements
  audit: log module name on init_module
  audit: log 32-bit socketcalls
  audit: add feature audit_lost reset
  audit: Make AUDIT_ANOM_ABEND event normalized
  audit: Make AUDIT_KERNEL event conform to the specification
2017-02-21 13:25:50 -08:00
Luis R. Rodriguez a5544880af module: fix memory leak on early load_module() failures
While looking for early possible module loading failures I was
able to reproduce a memory leak possible with kmemleak. There
are a few rare ways to trigger a failure:

  o we've run into a failure while processing kernel parameters
    (parse_args() returns an error)
  o mod_sysfs_setup() fails
  o we're a live patch module and copy_module_elf() fails

Chances of running into this issue is really low.

kmemleak splat:

unreferenced object 0xffff9f2c4ada1b00 (size 32):
  comm "kworker/u16:4", pid 82, jiffies 4294897636 (age 681.816s)
  hex dump (first 32 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8c6cfeba>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff8c200046>] __kmalloc_track_caller+0x126/0x230
    [<ffffffff8c1bc581>] kstrdup+0x31/0x60
    [<ffffffff8c1bc5d4>] kstrdup_const+0x24/0x30
    [<ffffffff8c3c23aa>] kvasprintf_const+0x7a/0x90
    [<ffffffff8c3b5481>] kobject_set_name_vargs+0x21/0x90
    [<ffffffff8c4fbdd7>] dev_set_name+0x47/0x50
    [<ffffffffc07819e5>] memstick_check+0x95/0x33c [memstick]
    [<ffffffff8c09c893>] process_one_work+0x1f3/0x4b0
    [<ffffffff8c09cb98>] worker_thread+0x48/0x4e0
    [<ffffffff8c0a2b79>] kthread+0xc9/0xe0
    [<ffffffff8c6dab5f>] ret_from_fork+0x1f/0x40
    [<ffffffffffffffff>] 0xffffffffffffffff

Cc: stable <stable@vger.kernel.org> # v2.6.30
Fixes: e180a6b775 ("param: fix charp parameters set via sysfs")
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2017-02-21 12:34:38 -08:00
Richard Guy Briggs ca86cad738 audit: log module name on init_module
This adds a new auxiliary record MODULE_INIT to the SYSCALL event.

We get finit_module for free since it made most sense to hook this in to
load_module().

https://github.com/linux-audit/audit-kernel/issues/7
https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-Load-Record-Format

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
[PM: corrected links in the commit description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-02-13 16:17:13 -05:00
Peter Zijlstra 5ff22646d2 module: Optimize search_module_extables()
While looking through the __ex_table stuff I found that we do a linear
lookup of the module. Also fix up a comment.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2017-02-10 19:21:10 -08:00
Paul Gortmaker 8a293be0d6 core: migrate exception table users off module.h and onto extable.h
These files were including module.h for exception table related
functions.  We've now separated that content out into its own file
"extable.h" so now move over to that and where possible, avoid all
the extra header content in module.h that we don't really need to
compile these non-modular files.

Note:
   init/main.c still needs module.h for __init_or_module
   kernel/extable.c still needs module.h for is_module_text_address

...and so we don't get the benefit of removing module.h from the cpp
feed for these two files, unlike the almost universal 1:1 exchange
of module.h for extable.h we were able to do in the arch dirs.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2017-02-09 16:38:53 -05:00
Laura Abbott 0f5bf6d0af arch: Rename CONFIG_DEBUG_RODATA and CONFIG_DEBUG_MODULE_RONX
Both of these options are poorly named. The features they provide are
necessary for system security and should not be considered debug only.
Change the names to CONFIG_STRICT_KERNEL_RWX and
CONFIG_STRICT_MODULE_RWX to better describe what these options do.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-02-07 12:32:52 -08:00
Ard Biesheuvel 71810db27c modversions: treat symbol CRCs as 32 bit quantities
The modversion symbol CRCs are emitted as ELF symbols, which allows us
to easily populate the kcrctab sections by relying on the linker to
associate each kcrctab slot with the correct value.

This has a couple of downsides:

 - Given that the CRCs are treated as memory addresses, we waste 4 bytes
   for each CRC on 64 bit architectures,

 - On architectures that support runtime relocation, a R_<arch>_RELATIVE
   relocation entry is emitted for each CRC value, which identifies it
   as a quantity that requires fixing up based on the actual runtime
   load offset of the kernel. This results in corrupted CRCs unless we
   explicitly undo the fixup (and this is currently being handled in the
   core module code)

 - Such runtime relocation entries take up 24 bytes of __init space
   each, resulting in a x8 overhead in [uncompressed] kernel size for
   CRCs.

Switching to explicit 32 bit values on 64 bit architectures fixes most
of these issues, given that 32 bit values are not treated as quantities
that require fixing up based on the actual runtime load offset.  Note
that on some ELF64 architectures [such as PPC64], these 32-bit values
are still emitted as [absolute] runtime relocatable quantities, even if
the value resolves to a build time constant.  Since relative relocations
are always resolved at build time, this patch enables MODULE_REL_CRCS on
powerpc when CONFIG_RELOCATABLE=y, which turns the absolute CRC
references into relative references into .rodata where the actual CRC
value is stored.

So redefine all CRC fields and variables as u32, and redefine the
__CRC_SYMBOL() macro for 64 bit builds to emit the CRC reference using
inline assembler (which is necessary since 64-bit C code cannot use
32-bit types to hold memory addresses, even if they are ultimately
resolved using values that do not exceed 0xffffffff).  To avoid
potential problems with legacy 32-bit architectures using legacy
toolchains, the equivalent C definition of the kcrctab entry is retained
for 32-bit architectures.

Note that this mostly reverts commit d4703aefdb ("module: handle ppc64
relocating kcrctabs when CONFIG_RELOCATABLE=y")

Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 08:28:25 -08:00
Joe Lawrence 7598d167df livepatch/module: print notice of TAINT_LIVEPATCH
Add back the "tainting kernel with TAINT_LIVEPATCH" kernel log message
that commit 2992ef29ae ("livepatch/module: make TAINT_LIVEPATCH
module-specific") dropped.  Now that it's a module-specific taint flag,
include the module name.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2017-01-30 17:07:32 -08:00
Larry Finger 5eb7c0d04f taint/module: Fix problems when out-of-kernel driver defines true or false
Commit 7fd8329ba5 ("taint/module: Clean up global and module taint
flags handling") used the key words true and false as character members
of a new struct. These names cause problems when out-of-kernel modules
such as VirtualBox include their own definitions of true and false.

Fixes: 7fd8329ba5 ("taint/module: Clean up global and module taint flags handling")
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2017-01-17 10:56:45 -08:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Linus Torvalds 4d98ead183 Modules updates for v4.10
Summary of modules changes for the 4.10 merge window:
 
 * The rodata= cmdline parameter has been extended to additionally
   apply to module mappings
 
 * Fix a hard to hit race between module loader error/clean up
   handling and ftrace registration
 
 * Some code cleanups, notably panic.c and modules code use a
   unified taint_flags table now. This is much cleaner than
   duplicating the taint flag code in modules.c
 
 Signed-off-by: Jessica Yu <jeyu@redhat.com>
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Merge tag 'modules-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull modules updates from Jessica Yu:
 "Summary of modules changes for the 4.10 merge window:

   - The rodata= cmdline parameter has been extended to additionally
     apply to module mappings

   - Fix a hard to hit race between module loader error/clean up
     handling and ftrace registration

   - Some code cleanups, notably panic.c and modules code use a unified
     taint_flags table now. This is much cleaner than duplicating the
     taint flag code in modules.c"

* tag 'modules-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: fix DEBUG_SET_MODULE_RONX typo
  module: extend 'rodata=off' boot cmdline parameter to module mappings
  module: Fix a comment above strong_try_module_get()
  module: When modifying a module's text ignore modules which are going away too
  module: Ensure a module's state is set accordingly during module coming cleanup code
  module: remove trailing whitespace
  taint/module: Clean up global and module taint flags handling
  modpost: free allocated memory
2016-12-14 20:12:43 -08:00
Linus Torvalds faaae2a581 Re-enable CONFIG_MODVERSIONS in a slightly weaker form
This enables CONFIG_MODVERSIONS again, but allows for missing symbol CRC
information in order to work around the issue that newer binutils
versions seem to occasionally drop the CRC on the floor.  binutils 2.26
seems to work fine, while binutils 2.27 seems to break MODVERSIONS of
symbols that have been defined in assembler files.

[ We've had random missing CRC's before - it may be an old problem that
  just is now reliably triggered with the weak asm symbols and a new
  version of binutils ]

Some day I really do want to remove MODVERSIONS entirely.  Sadly, today
does not appear to be that day: Debian people apparently do want the
option to enable MODVERSIONS to make it easier to have external modules
across kernel versions, and this seems to be a fairly minimal fix for
the annoying problem.

Cc: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-29 16:01:30 -08:00
AKASHI Takahiro 39290b389e module: extend 'rodata=off' boot cmdline parameter to module mappings
The current "rodata=off" parameter disables read-only kernel mappings
under CONFIG_DEBUG_RODATA:
    commit d2aa1acad2 ("mm/init: Add 'rodata=off' boot cmdline parameter
    to disable read-only kernel mappings")

This patch is a logical extension to module mappings ie. read-only mappings
at module loading can be disabled even if CONFIG_DEBUG_SET_MODULE_RONX
(mainly for debug use). Please note, however, that it only affects RO/RW
permissions, keeping NX set.

This is the first step to make CONFIG_DEBUG_SET_MODULE_RONX mandatory
(always-on) in the future as CONFIG_DEBUG_RODATA on x86 and arm64.

Suggested-by: and Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/r/20161114061505.15238-1-takahiro.akashi@linaro.org
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2016-11-27 16:15:33 -08:00
Miroslav Benes 71d9f50793 module: Fix a comment above strong_try_module_get()
The comment above strong_try_module_get() function is not true anymore.
Return values changed with commit c9a3ba55bb ("module: wait for
dependent modules doing init.").

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1611161635330.12580@pobox.suse.cz
[jeyu@redhat.com: style fixes to make checkpatch.pl happy]
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2016-11-26 11:18:03 -08:00
Aaron Tomlin 905dd707fc module: When modifying a module's text ignore modules which are going away too
By default, during the access permission modification of a module's core
and init pages, we only ignore modules that are malformed. Albeit for a
module which is going away, it does not make sense to change its text to
RO since the module should be RW, before deallocation.

This patch makes set_all_modules_text_ro() skip modules which are going
away too.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/r/1477560966-781-1-git-send-email-atomlin@redhat.com
[jeyu@redhat.com: add comment as suggested by Steven Rostedt]
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2016-11-26 11:18:03 -08:00
Aaron Tomlin 885a78d4a5 module: Ensure a module's state is set accordingly during module coming cleanup code
In load_module() in the event of an error, for e.g. unknown module
parameter(s) specified we go to perform some module coming clean up
operations. At this point the module is still in a "formed" state
when it is actually going away.

This patch updates the module's state accordingly to ensure anyone on the
module_notify_list waiting for a module going away notification will be
notified accordingly.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: http://lkml.kernel.org/r/1476980293-19062-2-git-send-email-atomlin@redhat.com
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2016-11-26 11:18:02 -08:00
Petr Mladek 7fd8329ba5 taint/module: Clean up global and module taint flags handling
The commit 66cc69e34e ("Fix: module signature vs tracepoints:
add new TAINT_UNSIGNED_MODULE") updated module_taint_flags() to
potentially print one more character. But it did not increase the
size of the corresponding buffers in m_show() and print_modules().

We have recently done the same mistake when adding a taint flag
for livepatching, see
https://lkml.kernel.org/r/cfba2c823bb984690b73572aaae1db596b54a082.1472137475.git.jpoimboe@redhat.com

Also struct module uses an incompatible type for mod-taints flags.
It survived from the commit 2bc2d61a96 ("[PATCH] list module
taint flags in Oops/panic"). There was used "int" for the global taint
flags at these times. But only the global tain flags was later changed
to "unsigned long" by the commit 25ddbb18aa ("Make the taint
flags reliable").

This patch defines TAINT_FLAGS_COUNT that can be used to create
arrays and buffers of the right size. Note that we could not use
enum because the taint flag indexes are used also in assembly code.

Then it reworks the table that describes the taint flags. The TAINT_*
numbers can be used as the index. Instead, we add information
if the taint flag is also shown per-module.

Finally, it uses "unsigned long", bit operations, and the updated
taint_flags table also for mod->taints.

It is not optimal because only few taint flags can be printed by
module_taint_flags(). But better be on the safe side. IMHO, it is
not worth the optimization and this is a good compromise.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: http://lkml.kernel.org/r/1474458442-21581-1-git-send-email-pmladek@suse.com
[jeyu@redhat.com: fix broken lkml link in changelog]
Signed-off-by: Jessica Yu <jeyu@redhat.com>
2016-11-26 11:18:01 -08:00
Josh Poimboeuf 2992ef29ae livepatch/module: make TAINT_LIVEPATCH module-specific
There's no reliable way to determine which module tainted the kernel
with TAINT_LIVEPATCH.  For example, /sys/module/<klp module>/taint
doesn't report it.  Neither does the "mod -t" command in the crash tool.

Make it crystal clear who the guilty party is by associating
TAINT_LIVEPATCH with any module which sets the "livepatch" modinfo
attribute.  The flag will still get set in the kernel like before, but
now it also sets the same flag in mod->taint.

Note that now the taint flag gets set when the module is loaded rather
than when it's enabled.

I also renamed find_livepatch_modinfo() to check_modinfo_livepatch() to
better reflect its purpose: it's basically a livepatch-specific
sub-function of check_modinfo().

Reported-by: Chunyu Hu <chuhu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-08-26 14:42:08 +02:00
Linus Torvalds fb1b83d3ff Removed the MODULE_SIG_FORCE-means-no-MODULE_FORCE_LOAD patch.
Only interesting thing here is Jessica's patch to add ro_after_init support
 to modules.  The rest are all trivia.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "The only interesting thing here is Jessica's patch to add
  ro_after_init support to modules.  The rest are all trivia"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  extable.h: add stddef.h so "NULL" definition is not implicit
  modules: add ro_after_init support
  jump_label: disable preemption around __module_text_address().
  exceptions: fork exception table content from module.h into extable.h
  modules: Add kernel parameter to blacklist modules
  module: Do a WARN_ON_ONCE() for assert module mutex not held
  Documentation/module-signing.txt: Note need for version info if reusing a key
  module: Invalidate signatures on force-loaded modules
  module: Issue warnings when tainting kernel
  module: fix redundant test.
  module: fix noreturn attribute for __module_put_and_exit()
2016-08-04 09:14:38 -04:00
Jessica Yu 444d13ff10 modules: add ro_after_init support
Add ro_after_init support for modules by adding a new page-aligned section
in the module layout (after rodata) for ro_after_init data and enabling RO
protection for that section after module init runs.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:55 +09:30
Prarit Bhargava be7de5f91f modules: Add kernel parameter to blacklist modules
Blacklisting a module in linux has long been a problem.  The current
procedure is to use rd.blacklist=module_name, however, that doesn't
cover the case after the initramfs and before a boot prompt (where one
is supposed to use /etc/modprobe.d/blacklist.conf to blacklist
runtime loading). Using rd.shell to get an early prompt is hit-or-miss,
and doesn't cover all situations AFAICT.

This patch adds this functionality of permanently blacklisting a module
by its name via the kernel parameter module_blacklist=module_name.

[v2]: Rusty, use core_param() instead of __setup() which simplifies
things.

[v3]: Rusty, undo wreckage from strsep()

[v4]: Rusty, simpler version of blacklisted()

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:53 +09:30
Steven Rostedt 9502514f28 module: Do a WARN_ON_ONCE() for assert module mutex not held
When running with lockdep enabled, I triggered the WARN_ON() in the
module code that asserts when module_mutex or rcu_read_lock_sched are
not held. The issue I have is that this can also be called from the
dump_stack() code, causing us to enter an infinite loop...

 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8fa70 ffff880215e8fa70 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8fac0 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8f7a0 ffff880215e8f7a0 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8f7f0 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
 Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14
 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
  ffff880215e8f4d0 ffff880215e8f4d0 ffffffff812fc8e3 0000000000000000
  ffffffff81d3e55b ffff880215e8f520 ffffffff8104fc88 ffffffff8104fcab
  0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001
 Call Trace:
  [<ffffffff812fc8e3>] dump_stack+0x67/0x90
  [<ffffffff8104fc88>] __warn+0xcb/0xe9
  [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e
[...]

Which gives us rather useless information. Worse yet, there's some race
that causes this, and I seldom trigger it, so I have no idea what
happened.

This would not be an issue if that warning was a WARN_ON_ONCE().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-04 10:16:52 +09:30
Luis de Bethencourt 9d5059c959 dynamic_debug: only add header when used
kernel.h header doesn't directly use dynamic debug, instead we can
include it in module.c (which used it via kernel.h).  printk.h only uses
it if CONFIG_DYNAMIC_DEBUG is on, changing the inclusion to only happen
in that case.

Link: http://lkml.kernel.org/r/1468429793-16917-1-git-send-email-luisbg@osg.samsung.com
[luisbg@osg.samsung.com: include dynamic_debug.h in drb_int.h]
  Link: http://lkml.kernel.org/r/1468447828-18558-2-git-send-email-luisbg@osg.samsung.com
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:03 -04:00
Ben Hutchings bca014caaa module: Invalidate signatures on force-loaded modules
Signing a module should only make it trusted by the specific kernel it
was built for, not anything else.  Loading a signed module meant for a
kernel with a different ABI could have interesting effects.
Therefore, treat all signatures as invalid when a module is
force-loaded.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Libor Pechacek 3205c36cf7 module: Issue warnings when tainting kernel
While most of the locations where a kernel taint bit is set are accompanied
with a warning message, there are two which set their bits silently.  If
the tainting module gets unloaded later on, it is almost impossible to tell
what was the reason for setting the flag.

Signed-off-by: Libor Pechacek <lpechacek@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Rusty Russell c75b590d60 module: fix redundant test.
[linux-4.5-rc4/kernel/module.c:1692]: (style) Redundant condition: attr.test.
'!attr.test || (attr.test && attr.test(mod))' is equivalent to '!attr.test ||
attr.test(mod)'

This code was added like this ten years ago, in c988d2b284
"modules: add version and srcversion to sysfs".

Reported-by: David Binderman <dcb314@hotmail.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Jiri Kosina bf262dcec6 module: fix noreturn attribute for __module_put_and_exit()
__module_put_and_exit() is makred noreturn in module.h declaration, but is
lacking the attribute in the definition, which makes some tools (such as
sparse) unhappy. Amend the definition with the attribute as well (and
reformat the declaration so that it uses more common format).

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-27 12:38:00 +09:30
Jessica Yu 1ce15ef4f6 module: preserve Elf information for livepatch modules
For livepatch modules, copy Elf section, symbol, and string information
from the load_info struct in the module loader. Persist copies of the
original symbol table and string table.

Livepatch manages its own relocation sections in order to reuse module
loader code to write relocations. Livepatch modules must preserve Elf
information such as section indices in order to apply livepatch relocation
sections using the module loader's apply_relocate_add() function.

In order to apply livepatch relocation sections, livepatch modules must
keep a complete copy of their original symbol table in memory. Normally, a
stripped down copy of a module's symbol table (containing only "core"
symbols) is made available through module->core_symtab. But for livepatch
modules, the symbol table copied into memory on module load must be exactly
the same as the symbol table produced when the patch module was compiled.
This is because the relocations in each livepatch relocation section refer
to their respective symbols with their symbol indices, and the original
symbol indices (and thus the symtab ordering) must be preserved in order
for apply_relocate_add() to find the right symbol.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-04-01 15:00:10 +02:00
Linus Torvalds 0f49fc95b8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching update from Jiri Kosina:

 - cleanup of module notifiers; this depends on a module.c cleanup which
   has been acked by Rusty; from Jessica Yu

 - small assorted fixes and MAINTAINERS update

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch/module: remove livepatch module notifier
  modules: split part of complete_formation() into prepare_coming_module()
  livepatch: Update maintainers
  livepatch: Fix the error message about unresolvable ambiguity
  klp: remove CONFIG_LIVEPATCH dependency from klp headers
  klp: remove superfluous errors in asm/livepatch.h
2016-03-17 21:46:32 -07:00
Linus Torvalds bb7aeae3d6 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security layer updates from James Morris:
 "There are a bunch of fixes to the TPM, IMA, and Keys code, with minor
  fixes scattered across the subsystem.

  IMA now requires signed policy, and that policy is also now measured
  and appraised"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (67 commits)
  X.509: Make algo identifiers text instead of enum
  akcipher: Move the RSA DER encoding check to the crypto layer
  crypto: Add hash param to pkcs1pad
  sign-file: fix build with CMS support disabled
  MAINTAINERS: update tpmdd urls
  MODSIGN: linux/string.h should be #included to get memcpy()
  certs: Fix misaligned data in extra certificate list
  X.509: Handle midnight alternative notation in GeneralizedTime
  X.509: Support leap seconds
  Handle ISO 8601 leap seconds and encodings of midnight in mktime64()
  X.509: Fix leap year handling again
  PKCS#7: fix unitialized boolean 'want'
  firmware: change kernel read fail to dev_dbg()
  KEYS: Use the symbol value for list size, updated by scripts/insert-sys-cert
  KEYS: Reserve an extra certificate symbol for inserting without recompiling
  modsign: hide openssl output in silent builds
  tpm_tis: fix build warning with tpm_tis_resume
  ima: require signed IMA policy
  ima: measure and appraise the IMA policy itself
  ima: load policy using path
  ...
2016-03-17 11:33:45 -07:00
Jessica Yu 7e545d6eca livepatch/module: remove livepatch module notifier
Remove the livepatch module notifier in favor of directly enabling and
disabling patches to modules in the module loader. Hard-coding the
function calls ensures that ftrace_module_enable() is run before
klp_module_coming() during module load, and that klp_module_going() is
run before ftrace_release_mod() during module unload. This way, ftrace
and livepatch code is run in the correct order during the module
load/unload sequence without dependence on the module notifier call chain.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-03-17 09:45:10 +01:00
Jessica Yu 4c973d1620 modules: split part of complete_formation() into prepare_coming_module()
Put all actions in complete_formation() that are performed after
module->state is set to MODULE_STATE_COMING into a separate function
prepare_coming_module(). This split prepares for the removal of the
livepatch module notifiers in favor of hard-coding function calls to
klp_module_{coming,going} in the module loader.

The complete_formation -> prepare_coming_module split will also make error
handling easier since we can jump to the appropriate error label to do any
module GOING cleanup after all the COMING-actions have completed.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-03-17 09:45:09 +01:00
Mimi Zohar a1db742094 module: replace copy_module_from_fd with kernel version
Replace copy_module_from_fd() with kernel_read_file_from_fd().

Although none of the upstreamed LSMs define a kernel_module_from_file
hook, IMA is called, based on policy, to prevent unsigned kernel modules
from being loaded by the original kernel module syscall and to
measure/appraise signed kernel modules.

The security function security_kernel_module_from_file() was called prior
to reading a kernel module.  Preventing unsigned kernel modules from being
loaded by the original kernel module syscall remains on the pre-read
kernel_read_file() security hook.  Instead of reading the kernel module
twice, once for measuring/appraising and again for loading the kernel
module, the signature validation is moved to the kernel_post_read_file()
security hook.

This patch removes the security_kernel_module_from_file() hook and security
call.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
2016-02-21 09:06:12 -05:00
Linus Torvalds 705d43dbe1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching fixes from Jiri Kosina:

 - regression (from 4.4) fix for ordering issue, introduced by an
   earlier ftrace change, that broke live patching of modules.

   The fix replaces the ftrace module notifier by direct call in order
   to make the ordering guaranteed and well-defined.  The patch, from
   Jessica Yu, has been acked both by Steven and Rusty

 - error message fix from Miroslav Benes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  ftrace/module: remove ftrace module notifier
  livepatch: change the error message in asm/livepatch.h header files
2016-02-18 16:34:15 -08:00
Jessica Yu 7dcd182bec ftrace/module: remove ftrace module notifier
Remove the ftrace module notifier in favor of directly calling
ftrace_module_enable() and ftrace_release_mod() in the module loader.
Hard-coding the function calls directly in the module loader removes
dependence on the module notifier call chain and provides better
visibility and control over what gets called when, which is important
to kernel utilities such as livepatch.

This fixes a notifier ordering issue in which the ftrace module notifier
(and hence ftrace_module_enable()) for coming modules was being called
after klp_module_notify(), which caused livepatch modules to initialize
incorrectly. This patch removes dependence on the module notifier call
chain in favor of hard coding the corresponding function calls in the
module loader. This ensures that ftrace and livepatch code get called in
the correct order on patch module load and unload.

Fixes: 5156dca34a ("ftrace: Fix the race between ftrace and insmod")
Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-02-17 22:14:06 +01:00
Rusty Russell 8244062ef1 modules: fix longstanding /proc/kallsyms vs module insertion race.
For CONFIG_KALLSYMS, we keep two symbol tables and two string tables.
There's one full copy, marked SHF_ALLOC and laid out at the end of the
module's init section.  There's also a cut-down version that only
contains core symbols and strings, and lives in the module's core
section.

After module init (and before we free the module memory), we switch
the mod->symtab, mod->num_symtab and mod->strtab to point to the core
versions.  We do this under the module_mutex.

However, kallsyms doesn't take the module_mutex: it uses
preempt_disable() and rcu tricks to walk through the modules, because
it's used in the oops path.  It's also used in /proc/kallsyms.
There's nothing atomic about the change of these variables, so we can
get the old (larger!) num_symtab and the new symtab pointer; in fact
this is what I saw when trying to reproduce.

By grouping these variables together, we can use a
carefully-dereferenced pointer to ensure we always get one or the
other (the free of the module init section is already done in an RCU
callback, so that's safe).  We allocate the init one at the end of the
module init section, and keep the core one inside the struct module
itself (it could also have been allocated at the end of the module
core, but that's probably overkill).

Reported-by: Weilong Chen <chenweilong@huawei.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=111541
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-02-03 16:58:15 +10:30
Rusty Russell 2e7bac5361 module: wrapper for symbol name.
This trivial wrapper adds clarity and makes the following patch
smaller.

Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-02-03 16:58:14 +10:30
Luis R. Rodriguez 4355efbd80 modules: fix modparam async_probe request
Commit f2411da746 ("driver-core: add driver module
asynchronous probe support") added async probe support,
in two forms:

  * in-kernel driver specification annotation
  * generic async_probe module parameter (modprobe foo async_probe)

To support the generic kernel parameter parse_args() was
extended via commit ecc8617053 ("module: add extra
argument for parse_params() callback") however commit
failed to f2411da746 failed to add the required argument.

This causes a crash then whenever async_probe generic
module parameter is used. This was overlooked when the
form in which in-kernel async probe support was reworked
a bit... Fix this as originally intended.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: stable@vger.kernel.org (4.2+)
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> [minimized]
2016-02-03 16:58:14 +10:30
Linus Torvalds 0f0836b7eb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching updates from Jiri Kosina:

 - RO/NX attribute fixes for patch module relocations from Josh
   Poimboeuf.  As part of this effort, module.c has been cleaned up as
   well and livepatching is piggy-backing on this cleanup.  Rusty is OK
   with this whole lot going through livepatching tree.

 - symbol disambiguation support from Chris J Arges.  That series is
   also

        Reviewed-by: Miroslav Benes <mbenes@suse.cz>

   but this came in only after I've alredy pushed out.  Didn't want to
   rebase because of that, hence I am mentioning it here.

 - symbol lookup fix from Miroslav Benes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: Cleanup module page permission changes
  module: keep percpu symbols in module's symtab
  module: clean up RO/NX handling.
  module: use a structure to encapsulate layout.
  gcov: use within_module() helper.
  module: Use the same logic for setting and unsetting RO/NX
  livepatch: function,sympos scheme in livepatch sysfs directory
  livepatch: add sympos as disambiguator field to klp_reloc
  livepatch: add old_sympos as disambiguator field to klp_func
2016-01-14 16:38:02 -08:00
Steven Rostedt (Red Hat) 049fb9bd41 ftrace/module: Call clean up function when module init fails early
If the module init code fails after calling ftrace_module_init() and before
calling do_init_module(), we can suffer from a memory leak. This is because
ftrace_module_init() allocates pages to store the locations that ftrace
hooks are placed in the module text. If do_init_module() fails, it still
calls the MODULE_GOING notifiers which will tell ftrace to do a clean up of
the pages it allocated for the module. But if load_module() fails before
then, the pages allocated by ftrace_module_init() will never be freed.

Call ftrace_release_mod() on the module if load_module() fails before
getting to do_init_module().

Link: http://lkml.kernel.org/r/567CEA31.1070507@intel.com

Reported-by: "Qiu, PeiyangX" <peiyangx.qiu@intel.com>
Fixes: a949ae560a "ftrace/module: Hardcode ftrace_module_init() call into load_module()"
Cc: stable@vger.kernel.org # v2.6.38+
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-01-07 12:17:39 -05:00
Miroslav Benes e022441851 module: keep percpu symbols in module's symtab
Currently, percpu symbols from .data..percpu ELF section of a module are
not copied over and stored in final symtab array of struct module.
Consequently such symbol cannot be returned via kallsyms API (for
example kallsyms_lookup_name). This can be especially confusing when the
percpu symbol is exported. Only its __ksymtab et al. are present in its
symtab.

The culprit is in layout_and_allocate() function where SHF_ALLOC flag is
dropped for .data..percpu section. There is in fact no need to copy the
section to final struct module, because kernel module loader allocates
extra percpu section by itself. Unfortunately only symbols from
SHF_ALLOC sections are copied due to a check in is_core_symbol().

The patch changes is_core_symbol() function to copy over also percpu
symbols (their st_shndx points to .data..percpu ELF section). We do it
only if CONFIG_KALLSYMS_ALL is set to be consistent with the rest of the
function (ELF section is SHF_ALLOC but !SHF_EXECINSTR). Finally
elf_type() returns type 'a' for a percpu symbol because its address is
absolute.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-04 22:46:26 +01:00
Rusty Russell 85c898db63 module: clean up RO/NX handling.
Modules have three sections: text, rodata and writable data.  The code
handled the case where these overlapped, however they never can:
debug_align() ensures they are always page-aligned.

This is why we got away with manually traversing the pages in
set_all_modules_text_rw() without rounding.

We create three helper functions: frob_text(), frob_rodata() and
frob_writable_data().  We then call these explicitly at every point,
so it's clear what we're doing.

We also expose module_enable_ro() and module_disable_ro() for
livepatch to use.

Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-04 22:46:26 +01:00
Rusty Russell 7523e4dc50 module: use a structure to encapsulate layout.
Makes it easier to handle init vs core cleanly, though the change is
fairly invasive across random architectures.

It simplifies the rbtree code immediately, however, while keeping the
core data together in the same cachline (now iff the rbtree code is
enabled).

Acked-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-04 22:46:25 +01:00
Josh Poimboeuf 20ef10c1b3 module: Use the same logic for setting and unsetting RO/NX
When setting a module's RO and NX permissions, set_section_ro_nx() is
used, but when clearing them, unset_module_{init,core}_ro_nx() are used.
The unset functions don't have the same checks the set function has for
partial page protections.  It's probably harmless, but it's still
confusingly asymmetrical.

Instead, use the same logic to do both.  Also add some new
set_module_{init,core}_ro_nx() helper functions for more symmetry with
the unset functions.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-12-04 22:46:24 +01:00
Peter Zijlstra 275d7d44d8 module: Fix locking in symbol_put_addr()
Poma (on the way to another bug) reported an assertion triggering:

  [<ffffffff81150529>] module_assert_mutex_or_preempt+0x49/0x90
  [<ffffffff81150822>] __module_address+0x32/0x150
  [<ffffffff81150956>] __module_text_address+0x16/0x70
  [<ffffffff81150f19>] symbol_put_addr+0x29/0x40
  [<ffffffffa04b77ad>] dvb_frontend_detach+0x7d/0x90 [dvb_core]

Laura Abbott <labbott@redhat.com> produced a patch which lead us to
inspect symbol_put_addr(). This function has a comment claiming it
doesn't need to disable preemption around the module lookup
because it holds a reference to the module it wants to find, which
therefore cannot go away.

This is wrong (and a false optimization too, preempt_disable() is really
rather cheap, and I doubt any of this is on uber critical paths,
otherwise it would've retained a pointer to the actual module anyway and
avoided the second lookup).

While its true that the module cannot go away while we hold a reference
on it, the data structure we do the lookup in very much _CAN_ change
while we do the lookup. Therefore fix the comment and add the
required preempt_disable().

Reported-by: poma <pomidorabelisima@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: a6e6abd575 ("module: remove module_text_address()")
Cc: stable@kernel.org
2015-08-24 10:37:01 +09:30
Rusty Russell fe0d34d242 module: weaken locking assertion for oops path.
We don't actually hold the module_mutex when calling find_module_all
from module_kallsyms_lookup_name: that's because it's used by the oops
code and we don't want to deadlock.

However, access to the list read-only is safe if preempt is disabled,
so we can weaken the assertion.  Keep a strong version for external
callers though.

Fixes: 0be964be0d ("module: Sanitize RCU usage and locking")
Reported-by: He Kuang <hekuang@huawei.com>
Cc: stable@kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-07-29 06:13:22 +09:30
Peter Zijlstra 758556bdc1 module: Fix load_module() error path
The load_module() error path frees a module but forgot to take it out
of the mod_tree, leaving a dangling entry in the tree, causing havoc.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
Tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
Fixes: 93c2e105f6 ("module: Optimize __module_address() using a latched RB-tree")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-07-09 06:57:12 +09:30