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| author | Yury Norov <ynorov@caviumnetworks.com> | 2018-04-05 16:18:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-05 21:36:21 -0700 |
| commit | 8351760ff5b2042039554b4948ddabaac644a976 (patch) | |
| tree | be731f914364e5b001db4e367be87f53fc2a4a12 /lib | |
| parent | 5df63c2a149ae65a9ec239e7c2af44efa6f79beb (diff) | |
| download | lwn-8351760ff5b2042039554b4948ddabaac644a976.tar.gz lwn-8351760ff5b2042039554b4948ddabaac644a976.zip | |
lib: fix stall in __bitmap_parselist()
syzbot is catching stalls at __bitmap_parselist()
(https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997a).
The trigger is
unsigned long v = 0;
bitmap_parselist("7:,", &v, BITS_PER_LONG);
which results in hitting infinite loop at
while (a <= b) {
off = min(b - a + 1, used_size);
bitmap_set(maskp, a, off);
a += group_size;
}
due to used_size == group_size == 0.
Link: http://lkml.kernel.org/r/20180404162647.15763-1-ynorov@caviumnetworks.com
Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster")
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+6887cbb011c8054e8a3d@syzkaller.appspotmail.com>
Cc: Noam Camus <noamca@mellanox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/bitmap.c | 2 | ||||
| -rw-r--r-- | lib/test_bitmap.c | 4 |
2 files changed, 5 insertions, 1 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 9e498c77ed0e..a42eff7e8c48 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -607,7 +607,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, /* if no digit is after '-', it's wrong*/ if (at_start && in_range) return -EINVAL; - if (!(a <= b) || !(used_size <= group_size)) + if (!(a <= b) || group_size == 0 || !(used_size <= group_size)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index b3f235baa05d..413367cf569e 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -255,6 +255,10 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = { {-EINVAL, "-1", NULL, 8, 0}, {-EINVAL, "-0", NULL, 8, 0}, {-EINVAL, "10-1", NULL, 8, 0}, + {-EINVAL, "0-31:", NULL, 8, 0}, + {-EINVAL, "0-31:0", NULL, 8, 0}, + {-EINVAL, "0-31:0/0", NULL, 8, 0}, + {-EINVAL, "0-31:1/0", NULL, 8, 0}, {-EINVAL, "0-31:10/1", NULL, 8, 0}, }; |