From 3bdd5ee0ec8c14131d560da492e6df452c6fdd75 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Wed, 9 Jun 2021 18:41:57 -0400 Subject: skbuff: fix incorrect msg_zerocopy copy notifications msg_zerocopy signals if a send operation required copying with a flag in serr->ee.ee_code. This field can be incorrect as of the below commit, as a result of both structs uarg and serr pointing into the same skb->cb[]. uarg->zerocopy must be read before skb->cb[] is reinitialized to hold serr. Similar to other fields len, hi and lo, use a local variable to temporarily hold the value. This was not a problem before, when the value was passed as a function argument. Fixes: 75518851a2a0 ("skbuff: Push status and refcounts into sock_zerocopy_callback") Reported-by: Talal Ahmad Signed-off-by: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/skbuff.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 3ad22870298c..bbc3b4b62032 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1253,6 +1253,7 @@ static void __msg_zerocopy_callback(struct ubuf_info *uarg) struct sock *sk = skb->sk; struct sk_buff_head *q; unsigned long flags; + bool is_zerocopy; u32 lo, hi; u16 len; @@ -1267,6 +1268,7 @@ static void __msg_zerocopy_callback(struct ubuf_info *uarg) len = uarg->len; lo = uarg->id; hi = uarg->id + len - 1; + is_zerocopy = uarg->zerocopy; serr = SKB_EXT_ERR(skb); memset(serr, 0, sizeof(*serr)); @@ -1274,7 +1276,7 @@ static void __msg_zerocopy_callback(struct ubuf_info *uarg) serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY; serr->ee.ee_data = hi; serr->ee.ee_info = lo; - if (!uarg->zerocopy) + if (!is_zerocopy) serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED; q = &sk->sk_error_queue; -- cgit v1.2.3-70-g09d2