From 531c9da8c854c5b075383253a57fdd4e0be82e99 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sun, 6 Feb 2011 23:26:43 +0000 Subject: [PATCH] batman-adv: Linearize fragment packets before merge We access the data inside the skbs of two fragments directly using memmove during the merge. The data of the skb could span over multiple skb pages. An direct access without knowledge about the pages would lead to an invalid memory access. Signed-off-by: Sven Eckelmann [lindner_marek@yahoo.de: Move return from function to the end] Signed-off-by: Marek Lindner --- net/batman-adv/unicast.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c index ee41fef04b21..d1a611322549 100644 --- a/net/batman-adv/unicast.c +++ b/net/batman-adv/unicast.c @@ -50,12 +50,12 @@ static struct sk_buff *frag_merge_packet(struct list_head *head, skb = tfp->skb; } + if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0) + goto err; + skb_pull(tmp_skb, sizeof(struct unicast_frag_packet)); - if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) { - /* free buffered skb, skb will be freed later */ - kfree_skb(tfp->skb); - return NULL; - } + if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) + goto err; /* move free entry to end */ tfp->skb = NULL; @@ -70,6 +70,11 @@ static struct sk_buff *frag_merge_packet(struct list_head *head, unicast_packet->packet_type = BAT_UNICAST; return skb; + +err: + /* free buffered skb, skb will be freed later */ + kfree_skb(tfp->skb); + return NULL; } static void frag_create_entry(struct list_head *head, struct sk_buff *skb) -- 2.20.1