Commit 773688a6cb ("kasan: use stack_depot_put for Generic mode") added
support for stack trace eviction for Generic KASAN.
However, that commit didn't evict stack traces when the object is not put
into quarantine. As a result, some stack traces are never evicted from
the stack depot.
In addition, with the "kasan: save mempool stack traces" series, the free
stack traces for mempool objects are also not properly evicted from the
stack depot.
Fix both issues by:
1. Evicting all stack traces when an object if freed if it was not put
into quarantine;
2. Always evicting an existing free stack trace when a new one is saved.
Also do a few related clean-ups:
- Do not zero out free track when initializing/invalidating free meta:
set a value in shadow memory instead;
- Rename KASAN_SLAB_FREETRACK to KASAN_SLAB_FREE_META;
- Drop the kasan_init_cache_meta function as it's not used by KASAN;
- Add comments for the kasan_alloc_meta and kasan_free_meta structs.
[akpm@linux-foundation.org: make release_free_meta() and release_alloc_meta() static]
Link: https://lkml.kernel.org/r/20231226225121.235865-1-andrey.konovalov@linux.dev
Fixes: 773688a6cb ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gcc-13 warns about function definitions for builtin interfaces that have a
different prototype, e.g.:
In file included from kasan_test.c:31:
kasan.h:574:6: error: conflicting types for built-in function '__asan_register_globals'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
574 | void __asan_register_globals(struct kasan_global *globals, size_t size);
kasan.h:577:6: error: conflicting types for built-in function '__asan_alloca_poison'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
577 | void __asan_alloca_poison(unsigned long addr, size_t size);
kasan.h:580:6: error: conflicting types for built-in function '__asan_load1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
580 | void __asan_load1(unsigned long addr);
kasan.h:581:6: error: conflicting types for built-in function '__asan_store1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
581 | void __asan_store1(unsigned long addr);
kasan.h:643:6: error: conflicting types for built-in function '__hwasan_tag_memory'; expected 'void(void *, unsigned char, long int)' [-Werror=builtin-declaration-mismatch]
643 | void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
The two problems are:
- Addresses are passes as 'unsigned long' in the kernel, but gcc-13
expects a 'void *'.
- sizes meant to use a signed ssize_t rather than size_t.
Change all the prototypes to match these. Using 'void *' consistently for
addresses gets rid of a couple of type casts, so push that down to the
leaf functions where possible.
This now passes all randconfig builds on arm, arm64 and x86, but I have
not tested it on the other architectures that support kasan, since they
tend to fail randconfig builds in other ways. This might fail if any of
the 32-bit architectures expect a 'long' instead of 'int' for the size
argument.
The __asan_allocas_unpoison() function prototype is somewhat weird, since
it uses a pointer for 'stack_top' and an size_t for 'stack_bottom'. This
looks like it is meant to be 'addr' and 'size' like the others, but the
implementation clearly treats them as 'top' and 'bottom'.
Link: https://lkml.kernel.org/r/20230509145735.9263-2-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make KASAN scan metadata to infer the requested allocation size instead of
printing cache->object_size.
This patch fixes confusing slab-out-of-bounds reports as reported in:
https://bugzilla.kernel.org/show_bug.cgi?id=216457
As an example of the confusing behavior, the report below hints that the
allocation size was 192, while the kernel actually called kmalloc(184):
==================================================================
BUG: KASAN: slab-out-of-bounds in _find_next_bit+0x143/0x160 lib/find_bit.c:109
Read of size 8 at addr ffff8880175766b8 by task kworker/1:1/26
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 184 bytes inside of
192-byte region [ffff888017576600, ffff8880175766c0)
...
Memory state around the buggy address:
ffff888017576580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888017576600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888017576680: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
^
ffff888017576700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888017576780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
With this patch, the report shows:
==================================================================
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 0 bytes to the right of
allocated 184-byte region [ffff888017576600, ffff8880175766b8)
...
==================================================================
Also report slab use-after-free bugs as "slab-use-after-free" and print
"freed" instead of "allocated" in the report when describing the accessed
memory region.
Also improve the metadata-related comment in kasan_find_first_bad_addr
and use addr_has_metadata across KASAN code instead of open-coding
KASAN_SHADOW_START checks.
[akpm@linux-foundation.org: fix printk warning]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216457
Link: https://lkml.kernel.org/r/20230129021437.18812-1-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Co-developed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add bug_type and alloc/free_track fields to kasan_report_info and add a
kasan_complete_mode_report_info() function that fills in these fields.
This function is implemented differently for different KASAN mode.
Change the reporting code to use the filled in fields instead of invoking
kasan_get_bug_type() and kasan_get_alloc/free_track().
For the Generic mode, kasan_complete_mode_report_info() invokes these
functions instead. For the tag-based modes, only the bug_type field is
filled in; alloc/free_track are handled in the next patch.
Using a single function that fills in these fields is required for the
tag-based modes, as the values for all three fields are determined in a
single procedure implemented in the following patch.
Link: https://lkml.kernel.org/r/8432b861054fa8d0cee79a8877dedeaf3b677ca8.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrey Konovalov
Arnd Bergmann
Kuan-Ying Lee
Zhiyuan Dai
Walter Wu