tipc: fix skb truesize/datasize ratio control
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Web: https://git.kernel.org/torvalds/c/55b3280d1e471795c08dbbe17325720a843e104c Commit: 55b3280d1e471795c08dbbe17325720a843e104c Parent: eb53f7af6f15285e2f6ada97285395343ce9f433 Refname: refs/heads/master Author: Hoang Le <[email protected]> AuthorDate: Thu Feb 8 17:16:25 2018 +0100 Committer: David S. Miller <[email protected]> CommitDate: Thu Feb 8 15:30:40 2018 -0500 tipc: fix skb truesize/datasize ratio control 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 <[email protected]> Signed-off-by: Jon Maloy <[email protected]> Signed-off-by: David S. Miller <[email protected]> --- 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 55d8ba92291d..4e1c6f6450bb 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); -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html