mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-03 07:38:10 +00:00
Code Issues Releases Wiki Activity

decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb

Browse source 
Verify that the length of the socket buffer is sufficient to cover the
entire nlh->nlmsg_len field before accessing that 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>
This commit is contained in:
Mateusz Jurczyk 2017-06-07 15:14:29 +02:00 committed by David S. Miller
parent ed66e50d95
commit 85eac2ba35
1 changed files with 3 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
net/decnet/netfilter/dn_rtmsg.c
View file

@ -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->nlmsg_len) ||
nlh->nlmsg_len < sizeof(*nlh) ||
skb->len < nlh->nlmsg_len)
return;
if (!netlink_capable(skb, CAP_NET_ADMIN))