Commit 64486697 authored Feb 16, 2012 by Xi Wang Committed by Alex Elder Mar 22, 2012

libceph: fix overflow check in crush_decode()



The existing overflow check (n > ULONG_MAX / b) didn't work, because
n = ULONG_MAX / b would both bypass the check and still overflow the
allocation size a + n * b.

The correct check should be (n > (ULONG_MAX - a) / b).

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

parent 810339ec

net/ceph/osdmap.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -283,7 +283,8 @@ static struct crush_map crush_decode(void pbyval, void *end)
		ceph_decode_32_safe(p, end, yes, bad);
		#if BITS_PER_LONG == 32
		err = -EINVAL;
		if (yes > ULONG_MAX / sizeof(struct crush_rule_step))
		if (yes > (ULONG_MAX - sizeof(*r))
		/ sizeof(struct crush_rule_step))
		goto bad;
		#endif
		r = c->rules[i] = kmalloc(sizeof(*r) +

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