path: root/net/ipx/af_ipx.c
diff options
authorHannes Frederic Sowa <hannes@stressinduktion.org>2013-11-21 03:14:22 +0100
committerDavid S. Miller <davem@davemloft.net>2013-11-20 21:52:30 -0500
commitf3d3342602f8bcbf37d7c46641cb9bca7618eb1c (patch)
tree11aebad9cca99426db27130b19417141259c81f4 /net/ipx/af_ipx.c
parentf873042093c0b418d2351fe142222b625c740149 (diff)
net: rework recvmsg handler msg_name and msg_namelen logic
This patch now always passes msg->msg_namelen as 0. recvmsg handlers must set msg_namelen to the proper size <= sizeof(struct sockaddr_storage) to return msg_name to the user. This prevents numerous uninitialized memory leaks we had in the recvmsg handlers and makes it harder for new code to accidentally leak uninitialized memory. Optimize for the case recvfrom is called with NULL as address. We don't need to copy the address at all, so set it to NULL before invoking the recvmsg handler. We can do so, because all the recvmsg handlers must cope with the case a plain read() is called on them. read() also sets msg_name to NULL. Also document these changes in include/linux/net.h as suggested by David Miller. Changes since RFC: Set msg->msg_name = NULL if user specified a NULL in msg_name but had a non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't affect sendto as it would bail out earlier while trying to copy-in the address. It also more naturally reflects the logic by the callers of verify_iovec. With this change in place I could remove " if (!uaddr || msg_sys->msg_namelen == 0) msg->msg_name = NULL ". This change does not alter the user visible error logic as we ignore msg_namelen as long as msg_name is NULL. Also remove two unnecessary curly brackets in ___sys_recvmsg and change comments to netdev style. Cc: David Miller <davem@davemloft.net> Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipx/af_ipx.c')
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
index 7a1e0fc1bd4d..e096025b477f 100644
--- a/net/ipx/af_ipx.c
+++ b/net/ipx/af_ipx.c
@@ -1823,8 +1823,6 @@ static int ipx_recvmsg(struct kiocb *iocb, struct socket *sock,
if (skb->tstamp.tv64)
sk->sk_stamp = skb->tstamp;
- msg->msg_namelen = sizeof(*sipx);
if (sipx) {
sipx->sipx_family = AF_IPX;
sipx->sipx_port = ipx->ipx_source.sock;
@@ -1832,6 +1830,7 @@ static int ipx_recvmsg(struct kiocb *iocb, struct socket *sock,
sipx->sipx_network = IPX_SKB_CB(skb)->ipx_source_net;
sipx->sipx_type = ipx->ipx_type;
sipx->sipx_zero = 0;
+ msg->msg_namelen = sizeof(*sipx);
rc = copied;

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