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2020-08-07kasan: adjust kasan_stack_oob for tag-based modeAndrey Konovalov
Use OOB_TAG_OFF as access offset to land the access into the next granule. Suggested-by: Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Elena Petrova <lenaptr@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Link: http://lkml.kernel.org/r/403b259f1de49a7a3694531c851ac28326a586a8.1596199677.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/3063ab1411e92bce36061a96e25b651212e70ba6.1596544734.git.andreyknvl@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07lib/test_kasan.c: fix KASAN unit tests for tag-based KASANWalter Wu
We use tag-based KASAN, then KASAN unit tests don't detect out-of-bounds memory access. They need to be fixed. With tag-based KASAN, the state of each 16 aligned bytes of memory is encoded in one shadow byte and the shadow value is tag of pointer, so we need to read next shadow byte, the shadow value is not equal to tag value of pointer, so that tag-based KASAN will detect out-of-bounds memory access. [walter-zh.wu@mediatek.com: use KASAN_SHADOW_SCALE_SIZE instead of 13] Link: http://lkml.kernel.org/r/20200708132524.11688-1-walter-zh.wu@mediatek.com Suggested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Link: http://lkml.kernel.org/r/20200706115039.16750-1-walter-zh.wu@mediatek.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07kasan: add tests for call_rcu stack recordingWalter Wu
Test call_rcu() call stack recording and verify whether it correctly is printed in KASAN report. Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Link: http://lkml.kernel.org/r/20200601051045.1294-1-walter-zh.wu@mediatek.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07mm, treewide: rename kzfree() to kfree_sensitive()Waiman Long
As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-03kasan: stop tests being eliminated as dead code with FORTIFY_SOURCEDaniel Axtens
Patch series "Fix some incompatibilites between KASAN and FORTIFY_SOURCE", v4. 3 KASAN self-tests fail on a kernel with both KASAN and FORTIFY_SOURCE: memchr, memcmp and strlen. When FORTIFY_SOURCE is on, a number of functions are replaced with fortified versions, which attempt to check the sizes of the operands. However, these functions often directly invoke __builtin_foo() once they have performed the fortify check. The compiler can detect that the results of these functions are not used, and knows that they have no other side effects, and so can eliminate them as dead code. Why are only memchr, memcmp and strlen affected? ================================================ Of string and string-like functions, kasan_test tests: * strchr -> not affected, no fortified version * strrchr -> likewise * strcmp -> likewise * strncmp -> likewise * strnlen -> not affected, the fortify source implementation calls the underlying strnlen implementation which is instrumented, not a builtin * strlen -> affected, the fortify souce implementation calls a __builtin version which the compiler can determine is dead. * memchr -> likewise * memcmp -> likewise * memset -> not affected, the compiler knows that memset writes to its first argument and therefore is not dead. Why does this not affect the functions normally? ================================================ In string.h, these functions are not marked as __pure, so the compiler cannot know that they do not have side effects. If relevant functions are marked as __pure in string.h, we see the following warnings and the functions are elided: lib/test_kasan.c: In function `kasan_memchr': lib/test_kasan.c:606:2: warning: statement with no effect [-Wunused-value] memchr(ptr, '1', size + 1); ^~~~~~~~~~~~~~~~~~~~~~~~~~ lib/test_kasan.c: In function `kasan_memcmp': lib/test_kasan.c:622:2: warning: statement with no effect [-Wunused-value] memcmp(ptr, arr, size+1); ^~~~~~~~~~~~~~~~~~~~~~~~ lib/test_kasan.c: In function `kasan_strings': lib/test_kasan.c:645:2: warning: statement with no effect [-Wunused-value] strchr(ptr, '1'); ^~~~~~~~~~~~~~~~ ... This annotation would make sense to add and could be added at any point, so the behaviour of test_kasan.c should change. The fix ======= Make all the functions that are pure write their results to a global, which makes them live. The strlen and memchr tests now pass. The memcmp test still fails to trigger, which is addressed in the next patch. [dja@axtens.net: drop patch 3] Link: http://lkml.kernel.org/r/20200424145521.8203-2-dja@axtens.net Fixes: 0c96350a2d2f ("lib/test_kasan.c: add tests for several string/memory API functions") Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: David Gow <davidgow@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Link: http://lkml.kernel.org/r/20200423154503.5103-1-dja@axtens.net Link: http://lkml.kernel.org/r/20200423154503.5103-2-dja@axtens.net Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02kasan: add test for invalid size in memmoveWalter Wu
Test negative size in memmove in order to verify whether it correctly get KASAN report. Casting negative numbers to size_t would indeed turn up as a large size_t, so it will have out-of-bounds bug and be detected by KASAN. [walter-zh.wu@mediatek.com: fix -Wstringop-overflow warning] Link: http://lkml.kernel.org/r/20200311134244.13016-1-walter-zh.wu@mediatek.com Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: kernel test robot <lkp@intel.com> Link: http://lkml.kernel.org/r/20191112065313.7060-1-walter-zh.wu@mediatek.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more()Gustavo A. R. Silva
In case memory resources for _ptr2_ were allocated, release them before return. Notice that in case _ptr1_ happens to be NULL, krealloc() behaves exactly like kmalloc(). Addresses-Coverity-ID: 1490594 ("Resource leak") Link: http://lkml.kernel.org/r/20200123160115.GA4202@embeddedor Fixes: 3f15801cdc23 ("lib: add kasan test module") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01kasan: add test for vmallocDaniel Axtens
Test kasan vmalloc support by adding a new test to the module. Link: http://lkml.kernel.org/r/20191031093909.9228-3-dja@axtens.net Signed-off-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24lib/test_kasan.c: add roundtrip testsMark Rutland
In several places we need to be able to operate on pointers which have gone via a roundtrip: virt -> {phys,page} -> virt With KASAN_SW_TAGS, we can't preserve the tag for SLUB objects, and the {phys,page} -> virt conversion will use KASAN_TAG_KERNEL. This patch adds tests to ensure that this works as expected, without false positives which have recently been spotted [1,2] in testing. [1] https://lore.kernel.org/linux-arm-kernel/20190819114420.2535-1-walter-zh.wu@mediatek.com/ [2] https://lore.kernel.org/linux-arm-kernel/20190819132347.GB9927@lakrids.cambridge.arm.com/ [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190821153927.28630-1-mark.rutland@arm.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12lib/test_kasan: Add test for double-kzfree detectionMarco Elver
Add a simple test that checks if double-kzfree is being detected correctly. Link: http://lkml.kernel.org/r/20190626142014.141844-4-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12lib/test_kasan: add bitops testsMarco Elver
Patch series "Bitops instrumentation for KASAN", v5. This patch (of 3): This adds bitops tests to the test_kasan module. In a follow-up patch, support for bitops instrumentation will be added. Link: http://lkml.kernel.org/r/20190613125950.197667-2-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-05kasan: remove use after scope bugs detection.Andrey Ryabinin
Use after scope bugs detector seems to be almost entirely useless for the linux kernel. It exists over two years, but I've seen only one valid bug so far [1]. And the bug was fixed before it has been reported. There were some other use-after-scope reports, but they were false-positives due to different reasons like incompatibility with structleak plugin. This feature significantly increases stack usage, especially with GCC < 9 version, and causes a 32K stack overflow. It probably adds performance penalty too. Given all that, let's remove use-after-scope detector entirely. While preparing this patch I've noticed that we mistakenly enable use-after-scope detection for clang compiler regardless of CONFIG_KASAN_EXTRA setting. This is also fixed now. [1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com> Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Will Deacon <will.deacon@arm.com> [arm64] Cc: Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26lib/test_kasan.c: add tests for several string/memory API functionsAndrey Ryabinin
Arch code may have asm implementation of string/memory API functions instead of using generic one from lib/string.c. KASAN don't see memory accesses in asm code, thus can miss many bugs. E.g. on ARM64 KASAN don't see bugs in memchr(), memcmp(), str[r]chr(), str[n]cmp(), str[n]len(). Add tests for these functions to be sure that we notice the problem on other architectures. Link: http://lkml.kernel.org/r/20180920135631.23833-3-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kyeongdon Kim <kyeongdon.kim@lge.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11kasan: fix invalid-free test crashing the kernelAndrey Konovalov
When an invalid-free is triggered by one of the KASAN tests, the object doesn't actually get freed. This later leads to a BUG failure in kmem_cache_destroy that checks that there are no allocated objects in the cache that is being destroyed. Fix this by calling kmem_cache_free with the proper object address after the call that triggers invalid-free. Link: http://lkml.kernel.org/r/286eaefc0a6c3fa9b83b87e7d6dc0fbb5b5c9926.1519924383.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Nick Terrell <terrelln@fb.com> Cc: Chris Mason <clm@fb.com> Cc: Yury Norov <ynorov@caviumnetworks.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Luis R . Rodriguez" <mcgrof@kernel.org> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Jeff Layton <jlayton@redhat.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Cc: Kostya Serebryany <kcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06kasan: remove redundant initialization of variable 'real_size'Colin Ian King
Variable real_size is initialized with a value that is never read, it is re-assigned a new value later on, hence the initialization is redundant and can be removed. Cleans up clang warning: lib/test_kasan.c:422:21: warning: Value stored to 'real_size' during its initialization is never read Link: http://lkml.kernel.org/r/20180206144950.32457-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06kasan: detect invalid freesDmitry Vyukov
Detect frees of pointers into middle of heap objects. Link: http://lkml.kernel.org/r/cb569193190356beb018a03bb8d6fbae67e7adbc.1514378558.git.dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06kasan: detect invalid frees for large objectsDmitry Vyukov
Patch series "kasan: detect invalid frees". KASAN detects double-frees, but does not detect invalid-frees (when a pointer into a middle of heap object is passed to free). We recently had a very unpleasant case in crypto code which freed an inner object inside of a heap allocation. This left unnoticed during free, but totally corrupted heap and later lead to a bunch of random crashes all over kernel code. Detect invalid frees. This patch (of 5): Detect frees of pointers into middle of large heap objects. I dropped const from kasan_kfree_large() because it starts propagating through a bunch of functions in kasan_report.c, slab/slub nearest_obj(), all of their local variables, fixup_red_left(), etc. Link: http://lkml.kernel.org/r/1b45b4fe1d20fc0de1329aab674c1dd973fee723.1514378558.git.dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06kasan: add tests for alloca poisoningPaul Lawrence
Link: http://lkml.kernel.org/r/20171204191735.132544-5-paullawrence@google.com Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Paul Lawrence <paullawrence@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17lib/test: delete five error messages for failed memory allocationsMarkus Elfring
Omit extra messages for a memory allocation failure in these functions. This issue was detected by using the Coccinelle software. Link: http://lkml.kernel.org/r/410a4c5a-4ee0-6fcc-969c-103d8e496b78@users.sourceforge.net Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31kasan: report only the first error by defaultMark Rutland
Disable kasan after the first report. There are several reasons for this: - Single bug quite often has multiple invalid memory accesses causing storm in the dmesg. - Write OOB access might corrupt metadata so the next report will print bogus alloc/free stacktraces. - Reports after the first easily could be not bugs by itself but just side effects of the first one. Given that multiple reports usually only do harm, it makes sense to disable kasan after the first one. If user wants to see all the reports, the boot-time parameter kasan_multi_shot must be used. [aryabinin@virtuozzo.com: wrote changelog and doc, added missing include] Link: http://lkml.kernel.org/r/20170323154416.30257-1-aryabinin@virtuozzo.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24kasan: add memcg kmem_cache testGreg Thelen
Make a kasan test which uses a SLAB_ACCOUNT slab cache. If the test is run within a non default memcg, then it uncovers the bug fixed by "kasan: drain quarantine of memcg slab objects"[1]. If run without fix [1] it shows "Slab cache still has objects", and the kmem_cache structure is leaked. Here's an unpatched kernel test: $ dmesg -c > /dev/null $ mkdir /sys/fs/cgroup/memory/test $ echo $$ > /sys/fs/cgroup/memory/test/tasks $ modprobe test_kasan 2> /dev/null $ dmesg | grep -B1 still [ 123.456789] kasan test: memcg_accounted_kmem_cache allocate memcg accounted object [ 124.456789] kmem_cache_destroy test_cache: Slab cache still has objects Kernels with fix [1] don't have the "Slab cache still has objects" warning or the underlying leak. The new test runs and passes in the default (root) memcg, though in the root memcg it won't uncover the problem fixed by [1]. Link: http://lkml.kernel.org/r/1482257462-36948-2-git-send-email-gthelen@google.com Signed-off-by: Greg Thelen <gthelen@google.com> Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-30kasan: support use-after-scope detectionDmitry Vyukov
Gcc revision 241896 implements use-after-scope detection. Will be available in gcc 7. Support it in KASAN. Gcc emits 2 new callbacks to poison/unpoison large stack objects when they go in/out of scope. Implement the callbacks and add a test. [dvyukov@google.com: v3] Link: http://lkml.kernel.org/r/1479998292-144502-1-git-send-email-dvyukov@google.com Link: http://lkml.kernel.org/r/1479226045-145148-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20kasan/tests: add tests for user memory access functionsAndrey Ryabinin
Add some tests for the newly-added user memory access API. Link: http://lkml.kernel.org/r/1462538722-1574-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20mm, kasan: add a ksize() testAlexander Potapenko
Add a test that makes sure ksize() unpoisons the whole chunk. Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Konstantin Serebryany <kcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25kasan: test fix: warn if the UAF could not be detected in kmalloc_uaf2Alexander Potapenko
Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25kasan: modify kmalloc_large_oob_right(), add kmalloc_pagealloc_oob_right()Alexander Potapenko
This patchset implements SLAB support for KASAN Unlike SLUB, SLAB doesn't store allocation/deallocation stacks for heap objects, therefore we reimplement this feature in mm/kasan/stackdepot.c. The intention is to ultimately switch SLUB to use this implementation as well, which will save a lot of memory (right now SLUB bloats each object by 256 bytes to store the allocation/deallocation stacks). Also neither SLUB nor SLAB delay the reuse of freed memory chunks, which is necessary for better detection of use-after-free errors. We introduce memory quarantine (mm/kasan/quarantine.c), which allows delayed reuse of deallocated memory. This patch (of 7): Rename kmalloc_large_oob_right() to kmalloc_pagealloc_oob_right(), as the test only checks the page allocator functionality. Also reimplement kmalloc_large_oob_right() so that the test allocates a large enough chunk of memory that still does not trigger the page allocator fallback. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05lib: test_kasan: add some testcasesWang Long
Add some out of bounds testcases to test_kasan module. Signed-off-by: Wang Long <long.wanglong@huawei.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10lib/test_kasan.c: make kmalloc_oob_krealloc_less more correctlyWang Long
In kmalloc_oob_krealloc_less, I think it is better to test the size2 boundary. If we do not call krealloc, the access of position size1 will still cause out-of-bounds and access of position size2 does not. After call krealloc, the access of position size2 cause out-of-bounds. So using size2 is more correct. Signed-off-by: Wang Long <long.wanglong@huawei.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10lib/test_kasan.c: fix a typoWang Long
Signed-off-by: Wang Long <long.wanglong@huawei.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13lib: add kasan test moduleAndrey Ryabinin
This is a test module doing various nasty things like out of bounds accesses, use after free. It is useful for testing kernel debugging features like kernel address sanitizer. It mostly concentrates on testing of slab allocator, but we might want to add more different stuff here in future (like stack/global variables out of bounds accesses and so on). Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>