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| author | Mateusz Jurczyk <mjurczyk@google.com> | 2017-06-07 16:14:29 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-05 14:41:34 +0200 |
| commit | d8d01fc9bad3e0d06c34cb4ed64254b34ca6da06 (patch) | |
| tree | 089d9526e2afbbb5a50c816a68f1f7ffb7bf42d5 /net | |
| parent | e34cacd27f477800cb37cffbd055b0560a94065e (diff) | |
| download | linux-stable-d8d01fc9bad3e0d06c34cb4ed64254b34ca6da06.tar.gz linux-stable-d8d01fc9bad3e0d06c34cb4ed64254b34ca6da06.tar.bz2 linux-stable-d8d01fc9bad3e0d06c34cb4ed64254b34ca6da06.zip | |
decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb
[ Upstream commit dd0da17b209ed91f39872766634ca967c170ada1 ]
Verify that the length of the socket buffer is sufficient to cover the
nlmsghdr structure before accessing the nlh->nlmsg_len field for further
input sanitization. If the client only supplies 1-3 bytes of data in
sk_buff, then nlh->nlmsg_len remains partially uninitialized and
contains leftover memory from the corresponding kernel allocation.
Operating on such data may result in indeterminate evaluation of the
nlmsg_len < sizeof(*nlh) expression.
The bug was discovered by a runtime instrumentation designed to detect
use of uninitialized memory in the kernel. The patch prevents this and
other similar tools (e.g. KMSAN) from flagging this behavior in the future.
Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/decnet/netfilter/dn_rtmsg.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c index 85f2fdc360c2..29246bc9a7b4 100644 --- a/net/decnet/netfilter/dn_rtmsg.c +++ b/net/decnet/netfilter/dn_rtmsg.c @@ -102,7 +102,9 @@ static inline void dnrmg_receive_user_skb(struct sk_buff *skb) { struct nlmsghdr *nlh = nlmsg_hdr(skb); - if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) + if (skb->len < sizeof(*nlh) || + nlh->nlmsg_len < sizeof(*nlh) || + skb->len < nlh->nlmsg_len) return; if (!netlink_capable(skb, CAP_NET_ADMIN)) |