Commits
Andrey Konovalov committed 5e82cd12038
kasan: introduce helper functions for determining bug type
Patch series "kasan: improve error reports", v2.
This patchset improves KASAN reports by making them easier to read and a
little more detailed. Also improves mm/kasan/report.c readability.
Effectively changes a use-after-free report to:
==================================================================
BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan]
Write of size 1 at addr ffff88006aa59da8 by task insmod/3951
CPU: 1 PID: 3951 Comm: insmod Tainted: G B 4.10.0+ #84
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x292/0x398
print_address_description+0x73/0x280
kasan_report.part.2+0x207/0x2f0
__asan_report_store1_noabort+0x2c/0x30
kmalloc_uaf+0xaa/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x7f22cfd0b9da
RSP: 002b:00007ffe69118a78 EFLAGS: 00000206 ORIG_RAX: 00000000000000af
RAX: ffffffffffffffda RBX: 0000555671242090 RCX: 00007f22cfd0b9da
RDX: 00007f22cffcaf88 RSI: 000000000004df7e RDI: 00007f22d0399000
RBP: 00007f22cffcaf88 R08: 0000000000000003 R09: 0000000000000000
R10: 00007f22cfd07d0a R11: 0000000000000206 R12: 0000555671243190
R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004
Allocated by task 3951:
save_stack_trace+0x16/0x20
save_stack+0x43/0xd0
kasan_kmalloc+0xad/0xe0
kmem_cache_alloc_trace+0x82/0x270
kmalloc_uaf+0x56/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc2
Freed by task 3951:
save_stack_trace+0x16/0x20
save_stack+0x43/0xd0
kasan_slab_free+0x72/0xc0
kfree+0xe8/0x2b0
kmalloc_uaf+0x85/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc
The buggy address belongs to the object at ffff88006aa59da0
which belongs to the cache kmalloc-16 of size 16
The buggy address is located 8 bytes inside of
16-byte region [ffff88006aa59da0, ffff88006aa59db0)
The buggy address belongs to the page:
page:ffffea0001aa9640 count:1 mapcount:0 mapping: (null) index:0x0
flags: 0x100000000000100(slab)
raw: 0100000000000100 0000000000000000 0000000000000000 0000000180800080
raw: ffffea0001abe380 0000000700000007 ffff88006c401b40 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88006aa59c80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
ffff88006aa59d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
>ffff88006aa59d80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
^
ffff88006aa59e00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
ffff88006aa59e80: fb fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
==================================================================
from:
==================================================================
BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] at addr ffff88006c4dcb28
Write of size 1 by task insmod/3984
CPU: 1 PID: 3984 Comm: insmod Tainted: G B 4.10.0+ #83
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x292/0x398
kasan_object_err+0x1c/0x70
kasan_report.part.1+0x20e/0x4e0
__asan_report_store1_noabort+0x2c/0x30
kmalloc_uaf+0xaa/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x7feca0f779da
RSP: 002b:00007ffdfeae5218 EFLAGS: 00000206 ORIG_RAX: 00000000000000af
RAX: ffffffffffffffda RBX: 000055a064c13090 RCX: 00007feca0f779da
RDX: 00007feca1236f88 RSI: 000000000004df7e RDI: 00007feca1605000
RBP: 00007feca1236f88 R08: 0000000000000003 R09: 0000000000000000
R10: 00007feca0f73d0a R11: 0000000000000206 R12: 000055a064c14190
R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004
Object at ffff88006c4dcb20, in cache kmalloc-16 size: 16
Allocated:
PID = 3984
save_stack_trace+0x16/0x20
save_stack+0x43/0xd0
kasan_kmalloc+0xad/0xe0
kmem_cache_alloc_trace+0x82/0x270
kmalloc_uaf+0x56/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc2
Freed:
PID = 3984
save_stack_trace+0x16/0x20
save_stack+0x43/0xd0
kasan_slab_free+0x73/0xc0
kfree+0xe8/0x2b0
kmalloc_uaf+0x85/0xb6 [test_kasan]
kmalloc_tests_init+0x4f/0xa48 [test_kasan]
do_one_initcall+0xf3/0x390
do_init_module+0x215/0x5d0
load_module+0x54de/0x82b0
SYSC_init_module+0x3be/0x430
SyS_init_module+0x9/0x10
entry_SYSCALL_64_fastpath+0x1f/0xc2
Memory state around the buggy address:
ffff88006c4dca00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
ffff88006c4dca80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
>ffff88006c4dcb00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
^
ffff88006c4dcb80: fb fb fc fc 00 00 fc fc fb fb fc fc fb fb fc fc
ffff88006c4dcc00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
==================================================================
This patch (of 9):
Introduce get_shadow_bug_type() function, which determines bug type
based on the shadow value for a particular kernel address. Introduce
get_wild_bug_type() function, which determines bug type for addresses
which don't have a corresponding shadow value.
Link: http://lkml.kernel.org/r/20170302134851.101218-2-andreyknvl@google.com
Signed-off-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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>