From: Jesper Juhl <jj@xxxxxxxxxxxxx>
ipq_build_packet_message() in net/ipv4/netfilter/ip_queue.c and
net/ipv6/netfilter/ip6_queue.c contain a small potential mem leak as
far as I can tell.
We allocate memory for 'skb' with alloc_skb() annd then call
nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
NLMSG_PUT is a macro
NLMSG_PUT(skb, pid, seq, type, len) \
NLMSG_NEW(skb, pid, seq, type, len, 0)
that expands to NLMSG_NEW, which is also a macro which expands to:
NLMSG_NEW(skb, pid, seq, type, len, flags) \
({ if (unlikely(skb_tailroom(skb) < (int)NLMSG_SPACE(len))) \
goto nlmsg_failure; \
__nlmsg_put(skb, pid, seq, type, len, flags); })
If we take the true branch of the 'if' statement and 'goto
nlmsg_failure', then we'll, at that point, return from
ipq_build_packet_message() without having assigned 'skb' to anything
and we'll leak the memory we allocated for it when it goes out of
scope.
Fix this by placing a 'kfree(skb)' at 'nlmsg_failure'.
I admit that I do not know how likely this to actually happen or even
if there's something that guarantees that it will never happen - I'm
not that familiar with this code, but if that is so, I've not been
able to spot it.
Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
net/ipv4/netfilter/ip_queue.c | 1 +
net/ipv6/netfilter/ip6_queue.c | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 5c9b9d9..48f7d5b 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -218,6 +218,7 @@ ipq_build_packet_message(struct nf_queue_entry *entry, int *errp)
return skb;
nlmsg_failure:
+ kfree_skb(skb);
*errp = -EINVAL;
printk(KERN_ERR "ip_queue: error creating packet message\n");
return NULL;
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 2493948..87b243a 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -218,6 +218,7 @@ ipq_build_packet_message(struct nf_queue_entry *entry, int *errp)
return skb;
nlmsg_failure:
+ kfree_skb(skb);
*errp = -EINVAL;
printk(KERN_ERR "ip6_queue: error creating packet message\n");
return NULL;
--
1.7.2.3
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