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authorWillem de Bruijn <willemb@google.com>2019-06-07 17:57:48 -0400
committerDavid S. Miller <davem@davemloft.net>2019-06-11 11:40:54 -0700
commit522924b583082f51b8a2406624a2f27c22119b20 (patch)
tree74e958e6694bd5adbd77ffc23e88f760f494c03f /net/ipv6/ip6_output.c
parentdce5ccccd1231c6eaec5ede80bce85f2ae536826 (diff)
net: correct udp zerocopy refcnt also when zerocopy only on append
The below patch fixes an incorrect zerocopy refcnt increment when appending with MSG_MORE to an existing zerocopy udp skb. send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt 1 send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt still 1 (bar frags) But it missed that zerocopy need not be passed at the first send. The right test whether the uarg is newly allocated and thus has extra refcnt 1 is not !skb, but !skb_zcopy. send(.., MSG_MORE); // <no uarg> send(.., MSG_ZEROCOPY); // refcnt 1 Fixes: 100f6d8e09905 ("net: correct zerocopy refcnt with udp MSG_MORE") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ip6_output.c')
-rw-r--r--net/ipv6/ip6_output.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 934c88f128ab..834475717110 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1340,7 +1340,7 @@ emsgsize:
uarg = sock_zerocopy_realloc(sk, length, skb_zcopy(skb));
if (!uarg)
return -ENOBUFS;
- extra_uref = !skb; /* only extra ref if !MSG_MORE */
+ extra_uref = !skb_zcopy(skb); /* only ref on new uarg */
if (rt->dst.dev->features & NETIF_F_SG &&
csummode == CHECKSUM_PARTIAL) {
paged = true;