linux/mm/kmsan
Sabyrzhan Tasbolatov e4137f0881 mm, kasan, kmsan: instrument copy_from/to_kernel_nofault
Instrument copy_from_kernel_nofault() with KMSAN for uninitialized kernel
memory check and copy_to_kernel_nofault() with KASAN, KCSAN to detect the
memory corruption.

syzbot reported that bpf_probe_read_kernel() kernel helper triggered KASAN
report via kasan_check_range() which is not the expected behaviour as
copy_from_kernel_nofault() is meant to be a non-faulting helper.

Solution is, suggested by Marco Elver, to replace KASAN, KCSAN check in
copy_from_kernel_nofault() with KMSAN detection of copying uninitilaized
kernel memory.  In copy_to_kernel_nofault() we can retain
instrument_write() explicitly for the memory corruption instrumentation.

copy_to_kernel_nofault() is tested on x86_64 and arm64 with
CONFIG_KASAN_SW_TAGS.  On arm64 with CONFIG_KASAN_HW_TAGS, kunit test
currently fails.  Need more clarification on it.

[akpm@linux-foundation.org: fix comment layout, per checkpatch
Link: https://lore.kernel.org/linux-mm/CANpmjNMAVFzqnCZhEity9cjiqQ9CVN1X7qeeeAp_6yKjwKo8iw@mail.gmail.com/
Link: https://lkml.kernel.org/r/20241011035310.2982017-1-snovitoll@gmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Reported-by: syzbot+61123a5daeb9f7454599@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599
Reported-by: Andrey Konovalov <andreyknvl@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=210505
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>	[KASAN]
Tested-by: Andrey Konovalov <andreyknvl@gmail.com>	[KASAN]
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:14 -08:00
..
core.c kmsan: add missing __user tags 2024-07-03 19:30:26 -07:00
hooks.c kmsan: do not pass NULL pointers as 0 2024-07-03 19:30:26 -07:00
init.c kmsan: accept ranges starting with 0 on s390 2024-07-03 19:30:23 -07:00
instrumentation.c kmsan: do not pass NULL pointers as 0 2024-07-03 19:30:26 -07:00
kmsan_test.c mm, kasan, kmsan: instrument copy_from/to_kernel_nofault 2024-11-06 20:11:14 -08:00
kmsan.h kmsan: add missing __user tags 2024-07-03 19:30:26 -07:00
Makefile kmsan: disable ftrace in kmsan core code 2023-02-20 12:46:16 -08:00
report.c kmsan: add missing __user tags 2024-07-03 19:30:26 -07:00
shadow.c kmsan: use ALIGN_DOWN() in kmsan_get_metadata() 2024-07-03 19:30:22 -07:00