Commit aea0929e authored May 18, 2015 by Eric B Munson Committed by David S. Miller May 19, 2015

tcp: Return error instead of partial read for saved syn headers



Currently the getsockopt() requesting the cached contents of the syn
packet headers will fail silently if the caller uses a buffer that is
too small to contain the requested data.  Rather than fail silently and
discard the headers, getsockopt() should return an error and report the
required size to hold the data.

Signed-off-by: Eric B Munson <emunson@akamai.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

parent c9a70d43

net/ipv4/tcp.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -2845,7 +2845,15 @@ static int do_tcp_getsockopt(struct sock *sk, int level,

		lock_sock(sk);
		if (tp->saved_syn) {
		len = min_t(unsigned int, tp->saved_syn[0], len);
		if (len < tp->saved_syn[0]) {
		if (put_user(tp->saved_syn[0], optlen)) {
		release_sock(sk);
		return -EFAULT;
		}
		release_sock(sk);
		return -EINVAL;
		}
		len = tp->saved_syn[0];
		if (put_user(len, optlen)) {
		release_sock(sk);
		return -EFAULT;