The patch titled
Subject: lib: Add might_fault() to strncpy_from_user.
has been added to the -mm tree. Its filename is
lib-add-might_fault-to-strncpy_from_user.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-add-might_fault-to-strncpy_from_user.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-add-might_fault-to-strncpy_from_user.patch
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------------------------------------------------------
From: KP Singh <kpsingh@xxxxxxxxxxxx>
Subject: 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.
Link: http://lkml.kernel.org/r/20200414225705.255711-1-kpsingh@xxxxxxxxxxxx
Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/strncpy_from_user.c | 1 +
1 file changed, 1 insertion(+)
--- a/lib/strncpy_from_user.c~lib-add-might_fault-to-strncpy_from_user
+++ a/lib/strncpy_from_user.c
@@ -98,6 +98,7 @@ long strncpy_from_user(char *dst, const
{
unsigned long max_addr, src_addr;
+ might_fault();
if (unlikely(count <= 0))
return 0;
_
Patches currently in -mm which might be from kpsingh@xxxxxxxxxxxx are
lib-add-might_fault-to-strncpy_from_user.patch
