From patchwork Tue Feb 19 18:49:21 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [58/81] packet: fix leakage of tx_ring memory Date: Tue, 19 Feb 2013 08:49:21 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 221827 Message-Id: <1361299784-8830-59-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Daniel Borkmann , Phil Sutter , Johann Baudy , "David S. Miller" 3.5.7.6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Phil Sutter commit 9665d5d62487e8e7b1f546c00e11107155384b9a upstream. When releasing a packet socket, the routine packet_set_ring() is reused to free rings instead of allocating them. But when calling it for the first time, it fills req->tp_block_nr with the value of rb->pg_vec_len which in the second invocation makes it bail out since req->tp_block_nr is greater zero but req->tp_block_size is zero. This patch solves the problem by passing a zeroed auto-variable to packet_set_ring() upon each invocation from packet_release(). As far as I can tell, this issue exists even since 69e3c75 (net: TX_RING and packet mmap), i.e. the original inclusion of TX ring support into af_packet, but applies only to sockets with both RX and TX ring allocated, which is probably why this was unnoticed all the time. Signed-off-by: Phil Sutter Cc: Johann Baudy Cc: Daniel Borkmann Acked-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Herton Ronaldo Krzesinski --- net/packet/af_packet.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 901cffd..02b1ef8 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2450,13 +2450,15 @@ static int packet_release(struct socket *sock) packet_flush_mclist(sk); - memset(&req_u, 0, sizeof(req_u)); - - if (po->rx_ring.pg_vec) + if (po->rx_ring.pg_vec) { + memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 0); + } - if (po->tx_ring.pg_vec) + if (po->tx_ring.pg_vec) { + memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 1); + } fanout_release(sk);