From: Mathias Krause <minipli@xxxxxxxxxxxxxx>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit 864745d291b5ba80ea0bd0edcbe67273de368836 upstream.
When dump_one_state() returns an error, e.g. because of a too small
buffer to dump the whole xfrm state, xfrm_state_netlink() returns NULL
instead of an error pointer. But its callers expect an error pointer
and therefore continue to operate on a NULL skbuff.
This could lead to a privilege escalation (execution of user code in
kernel context) if the attacker has CAP_NET_ADMIN and is able to map
address 0.
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Acked-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
net/xfrm/xfrm_user.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 44d18db58cbb..bbc09e0c1ae7 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -765,6 +765,7 @@ static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb,
{
struct xfrm_dump_info info;
struct sk_buff *skb;
+ int err;
skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
if (!skb)
@@ -775,9 +776,10 @@ static struct sk_buff *xfrm_state_netlink(struct sk_buff *in_skb,
info.nlmsg_seq = seq;
info.nlmsg_flags = 0;
- if (dump_one_state(x, 0, &info)) {
+ err = dump_one_state(x, 0, &info);
+ if (err) {
kfree_skb(skb);
- return NULL;
+ return ERR_PTR(err);
}
return skb;
--
1.8.5.2
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