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authorAlexey Kodanev <alexey.kodanev@oracle.com>2018-03-06 22:57:01 +0300
committerDavid S. Miller <davem@davemloft.net>2018-03-07 13:38:56 -0500
commit67f93df79aeefc3add4e4b31a752600f834236e2 (patch)
tree97dea36b4920e18f83a9918b812a35b65b7100e0 /net/dccp
parentl2tp: do not accept arbitrary sockets (diff)
downloadlinux-dev-67f93df79aeefc3add4e4b31a752600f834236e2.tar.xz
linux-dev-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.c5
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)