diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2015-04-15 19:00:32 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-04-19 10:10:47 +0200 |
| commit | 75a518b09f0939ad5d5bf12e91b9faec12c66d10 (patch) | |
| tree | 9fb19d7c2c4b1391041d3b14010b8a9378b7456e | |
| parent | 9dece36273f91a8e7467b7eadbe319fa924eec83 (diff) | |
tcp: Fix crash in TCP Fast Open
Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly")
changed tcp_send_syn_data() to perform an open-coded copy of the 'syn'
skb rather than using skb_copy_expand().
The open-coded copy does not cover the skb_shared_info::gso_segs
field, so in the new skb it is left set to 0. When this commit was
backported into stable branches between 3.10.y and 3.16.7-ckty
inclusive, it triggered the BUG() in tcp_transmit_skb().
Since Linux 3.18 the GSO segment count is kept in the
tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the
tcp_skb_cb structure to the new skb, so mainline and newer stable
branches are not affected.
Set skb_shared_info::gso_segs to the correct value of 1.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/tcp_output.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 913dc4f49b10..92b5e1f7d3b0 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2909,6 +2909,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) goto fallback; syn_data->ip_summed = CHECKSUM_PARTIAL; memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); + skb_shinfo(syn_data)->gso_segs = 1; if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space), fo->data->msg_iov, 0, space))) { kfree_skb(syn_data); |