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| author | Vegard Nossum <vegard.nossum@gmail.com> | 2008-12-26 02:21:17 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-12-26 02:21:17 +0100 |
| commit | 619e803d3c1b7bcc17c45e81f309d0b9b3df2d5d (patch) | |
| tree | c2c279dd155e07e96c7a2f483cce6c48c1640cd6 | |
| parent | tcp: Always set urgent pointer if it's beyond snd_nxt (diff) | |
| download | linux-619e803d3c1b7bcc17c45e81f309d0b9b3df2d5d.tar.xz linux-619e803d3c1b7bcc17c45e81f309d0b9b3df2d5d.zip | |
netlink: fix (theoretical) overrun in message iteration
See commit 1045b03e07d85f3545118510a587035536030c1c ("netlink: fix
overrun in attribute iteration") for a detailed explanation of why
this patch is necessary.
In short, nlmsg_next() can make "remaining" go negative, and the
remaining >= sizeof(...) comparison will promote "remaining" to an
unsigned type, which means that the expression will evaluate to
true for negative numbers, even though it was not intended.
I put "theoretical" in the title because I have no evidence that
this can actually happen, but I suspect that a crafted netlink
packet can trigger some badness.
Note that the last test, which seemingly has the exact same
problem (also true for nla_ok()), is perfectly OK, since we
already know that remaining is positive.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/netlink.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index 46b7764f1774..8a6150a3f4c7 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -332,7 +332,7 @@ static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen) */ static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining) { - return (remaining >= sizeof(struct nlmsghdr) && + return (remaining >= (int) sizeof(struct nlmsghdr) && nlh->nlmsg_len >= sizeof(struct nlmsghdr) && nlh->nlmsg_len <= remaining); } |