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| author | KP Singh <kpsingh@chromium.org> | 2020-06-04 16:50:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 19:06:25 -0700 |
| commit | 07887358993d48571f0f3a25cfce715564b35587 (patch) | |
| tree | 963fa448037023b18a406a6965d8b898a8743980 | |
| parent | 9ac17575804024fb3d5692cad7afc08929bab981 (diff) | |
| download | lwn-07887358993d48571f0f3a25cfce715564b35587.tar.gz lwn-07887358993d48571f0f3a25cfce715564b35587.zip | |
lib: Add might_fault() to strncpy_from_user.
When updating a piece of broken logic from using get_user to
strncpy_from_user, we noticed that a warning which is expected when
calling a function that might fault from an atomic context with
pagefaults enabled disappeared.
Not having this warning in place can lead to calling strncpy_from_user
from an atomic context and eventually kernel crashes/stack corruption.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jann Horn <jannh@google.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20200414225705.255711-1-kpsingh@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | lib/strncpy_from_user.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index b90ec550183a..34696a348864 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -98,6 +98,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count) { unsigned long max_addr, src_addr; + might_fault(); if (unlikely(count <= 0)) return 0; |