This is a note to let you know that I've just added the patch titled
decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
decnet-dn_rtmsg-improve-input-length-sanitization-in-dnrmg_receive_user_skb.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Jun 29 19:38:17 CEST 2017
From: Mateusz Jurczyk <mjurczyk@xxxxxxxxxx>
Date: Wed, 7 Jun 2017 16:14:29 +0200
Subject: decnet: dn_rtmsg: Improve input length sanitization in dnrmg_receive_user_skb
From: Mateusz Jurczyk <mjurczyk@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/decnet/netfilter/dn_rtmsg.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/decnet/netfilter/dn_rtmsg.c
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -102,7 +102,9 @@ static inline void dnrmg_receive_user_sk
{
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))
Patches currently in stable-queue which might be from mjurczyk@xxxxxxxxxx are
queue-4.4/decnet-dn_rtmsg-improve-input-length-sanitization-in-dnrmg_receive_user_skb.patch
queue-4.4/af_unix-add-sockaddr-length-checks-before-accessing-sa_family-in-bind-and-connect-handlers.patch