diff options
| author | Mateusz Jurczyk <mjurczyk@google.com> | 2017-06-07 17:14:29 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-05 15:35:12 +0300 |
| commit | 80f5fba8d14d799108395d49317c5b57615b6c73 (patch) | |
| tree | 4278c2868efa8c94a4b4615d5ef73856a9c67b8e /net/decnet | |
| parent | 0d487bc50728828ce0f6d817f2c4f8203568c1c8 (diff) | |
| download | linux-80f5fba8d14d799108395d49317c5b57615b6c73.tar.xz | |
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/decnet')
| -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 e4d9560a910b..3e4339c15670 100644 --- a/net/decnet/netfilter/dn_rtmsg.c +++ b/net/decnet/netfilter/dn_rtmsg.c @@ -104,7 +104,9 @@ 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)) |