[PATCH 3.4 17/27] net: rose: restore old recvmsg behavior

From: Greg Kroah-Hartman
Date: Mon Jan 13 2014 - 20:10:23 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Florian Westphal <fw@xxxxxxxxx>

[ Upstream commit f81152e35001e91997ec74a7b4e040e6ab0acccf ]

recvmsg handler in net/rose/af_rose.c performs size-check ->msg_namelen.

After commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c
(net: rework recvmsg handler msg_name and msg_namelen logic), we now
always take the else branch due to namelen being initialized to 0.

Digging in netdev-vger-cvs git repo shows that msg_namelen was
initialized with a fixed-size since at least 1995, so the else branch
was never taken.

Compile tested only.

Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/rose/af_rose.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)

--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -1257,6 +1257,7 @@ static int rose_recvmsg(struct kiocb *io

if (msg->msg_name) {
struct sockaddr_rose *srose;
+ struct full_sockaddr_rose *full_srose = msg->msg_name;

memset(msg->msg_name, 0, sizeof(struct full_sockaddr_rose));
srose = msg->msg_name;
@@ -1264,18 +1265,9 @@ static int rose_recvmsg(struct kiocb *io
srose->srose_addr = rose->dest_addr;
srose->srose_call = rose->dest_call;
srose->srose_ndigis = rose->dest_ndigis;
- if (msg->msg_namelen >= sizeof(struct full_sockaddr_rose)) {
- struct full_sockaddr_rose *full_srose = (struct full_sockaddr_rose *)msg->msg_name;
- for (n = 0 ; n < rose->dest_ndigis ; n++)
- full_srose->srose_digis[n] = rose->dest_digis[n];
- msg->msg_namelen = sizeof(struct full_sockaddr_rose);
- } else {
- if (rose->dest_ndigis >= 1) {
- srose->srose_ndigis = 1;
- srose->srose_digi = rose->dest_digis[0];
- }
- msg->msg_namelen = sizeof(struct sockaddr_rose);
- }
+ for (n = 0 ; n < rose->dest_ndigis ; n++)
+ full_srose->srose_digis[n] = rose->dest_digis[n];
+ msg->msg_namelen = sizeof(struct full_sockaddr_rose);
}

skb_free_datagram(sk, skb);


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