mptcp: Don't allow SOCK_ZEROCOPY

It's not tested and syzkaller found a leak. Let's just disable it for now. If somebody wants to support this feature, please go ahead :) Support for TCP ZEROCOPY was added in v4.14, so the faulting commit is the merge. Fixes: 42a0700 ("Merge tag 'v4.14-rc7' into mptcp_trunk") Signed-off-by: Christoph Paasch <[email protected]> Signed-off-by: Matthieu Baerts <[email protected]> (cherry picked from commit 838e4c4) Signed-off-by: Matthieu Baerts <[email protected]> (cherry picked from commit aaaf577) Signed-off-by: Matthieu Baerts <[email protected]>
multipath-tcp · Apr 1, 2022 · 611ae2e · 611ae2e
1 parent 1f40fde
commit 611ae2e
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/net/core/sock.c b/net/core/sock.c
@@ -1020,7 +1020,8 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 
 	case SO_ZEROCOPY:
 		if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6) {
-			if (sk->sk_protocol != IPPROTO_TCP)
+			if (sk->sk_protocol != IPPROTO_TCP ||
+			    sock_flag(sk, SOCK_MPTCP))
 				ret = -ENOTSUPP;
 		} else if (sk->sk_family != PF_RDS) {
 			ret = -ENOTSUPP;

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
@@ -3251,7 +3251,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 #ifdef CONFIG_MPTCP
 	case MPTCP_ENABLED:
 		if (mptcp_init_failed || !sysctl_mptcp_enabled ||
-		    sk->sk_state != TCP_CLOSE
+		    sk->sk_state != TCP_CLOSE ||
+		    sock_flag(sk, SOCK_ZEROCOPY)
 #ifdef CONFIG_TCP_MD5SIG
 		    || tp->md5sig_info
 #endif