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fs/dcache: Use read_word_at_a_time() in dentry_string_cmp()

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dentry_string_cmp() performs the word-at-a-time reads from 'cs' and may
read slightly more than it was requested in kmallac().  Normally this
would make KASAN to report out-of-bounds access, but this was
workarounded by commit df4c0e36f1 ("fs: dcache: manually unpoison
dname after allocation to shut up kasan's reports").

This workaround is not perfect, since it allows out-of-bounds access to
dentry's name for all the code, not just in dentry_string_cmp().

So it would be better to use read_word_at_a_time() instead and revert
commit df4c0e36f1.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Ryabinin 2018-02-01 21:00:51 +03:00 committed by Linus Torvalds
parent 1a3241ff10
commit bfe7aa6c39
1 changed files with 1 additions and 1 deletions
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2
fs/dcache.c
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@ -195,7 +195,7 @@ static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char
unsigned long a,b,mask;
for (;;) {
a = *(unsigned long *)cs;
a = read_word_at_a_time(cs);
b = load_unaligned_zeropad(ct);
if (tcount < sizeof(unsigned long))
break;