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authorPhil Sutter <phil.sutter@viprinet.com>2013-02-01 11:21:41 +0400
committerDavid S. Miller <davem@davemloft.net>2013-02-04 01:15:23 +0400
commit9665d5d62487e8e7b1f546c00e11107155384b9a (patch)
tree940f4891ea7cff0760ec26ab9a3e03817abcf4f1 /net/packet
parent92df9b217ee2392024483ba5b85a88d92d60f3c1 (diff)
downloadlinux-9665d5d62487e8e7b1f546c00e11107155384b9a.tar.xz
packet: fix leakage of tx_ring memory
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 <phil.sutter@viprinet.com> Cc: Johann Baudy <johann.baudy@gnu-log.net> Cc: Daniel Borkmann <dborkman@redhat.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e639645e8fec..c111bd0e083a 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2361,13 +2361,15 @@ 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);