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| author | Alexey Kodanev <alexey.kodanev@oracle.com> | 2018-03-06 22:57:01 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-03-07 13:38:56 -0500 |
| commit | 67f93df79aeefc3add4e4b31a752600f834236e2 (patch) | |
| tree | 97dea36b4920e18f83a9918b812a35b65b7100e0 /net/dccp | |
| parent | 17cfe79a65f98abe535261856c5aef14f306dff7 (diff) | |
| download | linux-67f93df79aeefc3add4e4b31a752600f834236e2.tar.gz linux-67f93df79aeefc3add4e4b31a752600f834236e2.tar.bz2 linux-67f93df79aeefc3add4e4b31a752600f834236e2.zip | |
dccp: check sk for closed state in dccp_sendmsg()
dccp_disconnect() sets 'dp->dccps_hc_tx_ccid' tx handler to NULL,
therefore if DCCP socket is disconnected and dccp_sendmsg() is
called after it, it will cause a NULL pointer dereference in
dccp_write_xmit().
This crash and the reproducer was reported by syzbot. Looks like
it is reproduced if commit 69c64866ce07 ("dccp: CVE-2017-8824:
use-after-free in DCCP code") is applied.
Reported-by: syzbot+f99ab3887ab65d70f816@syzkaller.appspotmail.com
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp')
| -rw-r--r-- | net/dccp/proto.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 15bdc002d90c..84cd4e3fd01b 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -794,6 +794,11 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (skb == NULL) goto out_release; + if (sk->sk_state == DCCP_CLOSED) { + rc = -ENOTCONN; + goto out_discard; + } + skb_reserve(skb, sk->sk_prot->max_header); rc = memcpy_from_msg(skb_put(skb, len), msg, len); if (rc != 0) |