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authorJesper Juhl <jj@chaosbits.net>2011-01-13 21:53:38 +0100
committerSven Eckelmann <sven@narfation.org>2011-01-13 22:11:12 +0100
commited7809d9c41b514115ddffaa860694393c2016b3 (patch)
treeef0e14d7477b2363f787ace24b683a439ea103f2
parent53320fe3bb1b1eef1aaff8dd47aae530ebeeb1e5 (diff)
downloadop-kernel-dev-ed7809d9c41b514115ddffaa860694393c2016b3.zip
op-kernel-dev-ed7809d9c41b514115ddffaa860694393c2016b3.tar.gz
batman-adv: Even Batman should not dereference NULL pointers
There's a problem in net/batman-adv/unicast.c::frag_send_skb(). dev_alloc_skb() allocates memory and may fail, thus returning NULL. If this happens we'll pass a NULL pointer on to skb_split() which in turn hands it to skb_split_inside_header() from where it gets passed to skb_put() that lets skb_tail_pointer() play with it and that function dereferences it. And thus the bat dies. While I was at it I also moved the call to dev_alloc_skb() above the assignment to 'unicast_packet' since there's no reason to do that assignment if the memory allocation fails. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Sven Eckelmann <sven@narfation.org>
-rw-r--r--net/batman-adv/unicast.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index dc2e28b..ee41fef 100644
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -229,10 +229,12 @@ int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
if (!bat_priv->primary_if)
goto dropped;
- unicast_packet = (struct unicast_packet *) skb->data;
+ frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
+ if (!frag_skb)
+ goto dropped;
+ unicast_packet = (struct unicast_packet *) skb->data;
memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
- frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
skb_split(skb, frag_skb, data_len / 2);
if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
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