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authorThomas Graf <tgraf@suug.ch>2013-11-30 13:21:31 +0100
committerJesse Gross <jesse@nicira.com>2014-01-06 15:52:06 -0800
commitaae9f0e22c07f6b97752741156ac0b3637d37a1a (patch)
tree164aafabd87e384e55527a37ab67761ef7473c86 /net/netlink
parentbb9b18fb55b03477fe5bdd3e97245d6d4d3dee4f (diff)
downloadop-kernel-dev-aae9f0e22c07f6b97752741156ac0b3637d37a1a.zip
op-kernel-dev-aae9f0e22c07f6b97752741156ac0b3637d37a1a.tar.gz
netlink: Avoid netlink mmap alloc if msg size exceeds frame size
An insufficent ring frame size configuration can lead to an unnecessary skb allocation for every Netlink message. Check frame size before taking the queue lock and allocating the skb and re-check with lock to be safe. Signed-off-by: Thomas Graf <tgraf@suug.ch> Reviewed-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index bca50b9..6433489 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1769,6 +1769,9 @@ struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
if (ring->pg_vec == NULL)
goto out_put;
+ if (ring->frame_size - NL_MMAP_HDRLEN < size)
+ goto out_put;
+
skb = alloc_skb_head(gfp_mask);
if (skb == NULL)
goto err1;
@@ -1778,6 +1781,7 @@ struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
if (ring->pg_vec == NULL)
goto out_free;
+ /* check again under lock */
maxlen = ring->frame_size - NL_MMAP_HDRLEN;
if (maxlen < size)
goto out_free;
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