[PATCH] net: Fix potential out of bound write in skb_try_coalesce()

[linmiaohe]

From: Miaohe Lin <linmiaohe@xxxxxxxxxx>

The head_frag of skb would occupy one extra skb_frag_t. Take it into
account or out of bound write to skb frags may happen.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8a0c39e4ab0a..b489ba201fac 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5154,7 +5154,7 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 		unsigned int offset;
 
 		if (to_shinfo->nr_frags +
-		    from_shinfo->nr_frags >= MAX_SKB_FRAGS)
+		    from_shinfo->nr_frags + 1 >= MAX_SKB_FRAGS)
 			return false;
 
 		if (skb_head_is_locked(from))
-- 
2.19.1