diff options
| author | Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-11-21 03:14:22 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-08 07:29:13 -0800 |
| commit | 0cefe287488ca07c0d7962a7b4d3fbb829d09917 (patch) | |
| tree | 74a7e354e890c2195f698b2820981e0a2bc10376 /net/ax25 | |
| parent | 086663e065ba2383382d6bb7d8a3d9bc9cba7cdf (diff) | |
net: rework recvmsg handler msg_name and msg_namelen logic
[ Upstream commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ax25')
| -rw-r--r-- | net/ax25/af_ax25.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index 4b4d2b779ec1..78c474f8f615 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1636,11 +1636,11 @@ static int ax25_recvmsg(struct kiocb *iocb, struct socket *sock, skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); - if (msg->msg_namelen != 0) { - struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name; + if (msg->msg_name) { ax25_digi digi; ax25_address src; const unsigned char *mac = skb_mac_header(skb); + struct sockaddr_ax25 *sax = msg->msg_name; memset(sax, 0, sizeof(struct full_sockaddr_ax25)); ax25_addr_parse(mac + 1, skb->data - mac - 1, &src, NULL, |