diff options
| author | R. Parameswaran <parameswaran.r7@gmail.com> | 2017-04-12 18:31:04 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-17 13:01:48 -0400 |
| commit | 57240d007816486131bee88cd474c2a71f0fe224 (patch) | |
| tree | eb6a94027fd814fd1a468ee127340b6201056bfd | |
| parent | 4a6e3c5def13c91adf2acc613837001f09af3baa (diff) | |
| download | lwn-57240d007816486131bee88cd474c2a71f0fe224.tar.gz lwn-57240d007816486131bee88cd474c2a71f0fe224.zip | |
l2tp: device MTU setup, tunnel socket needs a lock
The MTU overhead calculation in L2TP device set-up
merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
needs to be adjusted to lock the tunnel socket while
referencing the sub-data structures to derive the
socket's IP overhead.
Reported-by: Guillaume Nault <g.nault@alphalink.fr>
Tested-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: R. Parameswaran <rparames@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/net.h | 2 | ||||
| -rw-r--r-- | net/l2tp/l2tp_eth.c | 2 | ||||
| -rw-r--r-- | net/socket.c | 2 |
3 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/net.h b/include/linux/net.h index a42fab24c8af..abcfa46a2bd9 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -298,7 +298,7 @@ int kernel_sendpage(struct socket *sock, struct page *page, int offset, int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg); int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how); -/* Following routine returns the IP overhead imposed by a socket. */ +/* Routine returns the IP overhead imposed by a (caller-protected) socket. */ u32 kernel_sock_ip_overhead(struct sock *sk); #define MODULE_ALIAS_NETPROTO(proto) \ diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c index 138566a63123..b722d559c544 100644 --- a/net/l2tp/l2tp_eth.c +++ b/net/l2tp/l2tp_eth.c @@ -225,7 +225,9 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, dev->needed_headroom += session->hdr_len; return; } + lock_sock(tunnel->sock); l3_overhead = kernel_sock_ip_overhead(tunnel->sock); + release_sock(tunnel->sock); if (l3_overhead == 0) { /* L3 Overhead couldn't be identified, this could be * because tunnel->sock was NULL or the socket's diff --git a/net/socket.c b/net/socket.c index eea997036ada..c2564eb25c6b 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3360,7 +3360,7 @@ EXPORT_SYMBOL(kernel_sock_shutdown); /* This routine returns the IP overhead imposed by a socket i.e. * the length of the underlying IP header, depending on whether * this is an IPv4 or IPv6 socket and the length from IP options turned - * on at the socket. + * on at the socket. Assumes that the caller has a lock on the socket. */ u32 kernel_sock_ip_overhead(struct sock *sk) { |