From: Hoang Le hoang.h.le@dektek.com.au
[ Upstream commit 55b3280d1e471795c08dbbe17325720a843e104c ]
In commit d618d09a68e4 ("tipc: enforce valid ratio between skb truesize and contents") we introduced a test for ensuring that the condition truesize/datasize <= 4 is true for a received buffer. Unfortunately this test has two problems.
- Because of the integer arithmetics the test if (skb->truesize / buf_roundup_len(skb) > 4) will miss all ratios [4 < ratio < 5], which was not the intention. - The buffer returned by skb_copy() inherits skb->truesize of the original buffer, which doesn't help the situation at all.
In this commit, we change the ratio condition and replace skb_copy() with a call to skb_copy_expand() to finally get this right.
Acked-by: Jon Maloy jon.maloy@ericsson.com Signed-off-by: Jon Maloy jon.maloy@ericsson.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- net/tipc/msg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/tipc/msg.c b/net/tipc/msg.c index b0d07b35909d..fb8dda66db6d 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -208,8 +208,8 @@ bool tipc_msg_validate(struct sk_buff **_skb) int msz, hsz;
/* Ensure that flow control ratio condition is satisfied */ - if (unlikely(skb->truesize / buf_roundup_len(skb) > 4)) { - skb = skb_copy(skb, GFP_ATOMIC); + if (unlikely(skb->truesize / buf_roundup_len(skb) >= 4)) { + skb = skb_copy_expand(skb, BUF_HEADROOM, 0, GFP_ATOMIC); if (!skb) return false; kfree_skb(*_skb);