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| author | Phil Sutter <phil.sutter@viprinet.com> | 2013-02-01 07:21:41 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-14 10:47:34 -0800 |
| commit | 069d8ee0271bdf29ac0fc1186cbedb3815f94255 (patch) | |
| tree | 382f61c4da0eef4dd7f3c86d42a37678613708ce /net | |
| parent | d72b29e562214c7c5b635c3f44884a37bd115739 (diff) | |
| download | lwn-069d8ee0271bdf29ac0fc1186cbedb3815f94255.tar.gz lwn-069d8ee0271bdf29ac0fc1186cbedb3815f94255.zip | |
packet: fix leakage of tx_ring memory
[ Upstream commit 9665d5d62487e8e7b1f546c00e11107155384b9a ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/packet/af_packet.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 1ab5a0203ace..4058afe0c5ab 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1349,13 +1349,15 @@ static int packet_release(struct socket *sock) packet_flush_mclist(sk); - memset(&req, 0, sizeof(req)); - - if (po->rx_ring.pg_vec) + if (po->rx_ring.pg_vec) { + memset(&req, 0, sizeof(req)); packet_set_ring(sk, &req, 1, 0); + } - if (po->tx_ring.pg_vec) + if (po->tx_ring.pg_vec) { + memset(&req, 0, sizeof(req)); packet_set_ring(sk, &req, 1, 1); + } synchronize_net(); /* |