Subject: [PATCH 17/28] macvtap: fix TUNSETSNDBUF values > 64k

From: "Michael S. Tsirkin" <[email-masked]>
Date: Fri, 18 Sep 2015 13:41:09 +0300

[ Upstream commit 3ea79249e81e5ed051f2e6480cbde896d99046e8 ]

Upon TUNSETSNDBUF,  macvtap reads the requested sndbuf size into
a local variable u.
commit 39ec7de7092b ("macvtap: fix uninitialized access on
TUNSETIFF") changed its type to u16 (which is the right thing to
do for all other macvtap ioctls), breaking all values > 64k.

The value of TUNSETSNDBUF is actually a signed 32 bit integer, so
the right thing to do is to read it into an int.

Cc: David S. Miller <[email-masked]>
Fixes: 39ec7de7092b ("macvtap: fix uninitialized access on TUNSETIFF")
Reported-by: Mark A. Peloquin
Bisected-by: Matthew Rosato <[email-masked]>
Reported-by: Christian Borntraeger <[email-masked]>
Signed-off-by: Michael S. Tsirkin <[email-masked]>
Tested-by:  Matthew Rosato <[email-masked]>
Acked-by: Christian Borntraeger <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/macvtap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 8c350c5..58858c5 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -1054,10 +1054,10 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
 		return 0;
 
 	case TUNSETSNDBUF:
-		if (get_user(u, up))
+		if (get_user(s, sp))
 			return -EFAULT;
 
-		q->sk.sk_sndbuf = u;
+		q->sk.sk_sndbuf = s;
 		return 0;
 
 	case TUNGETVNETHDRSZ:
-- 
2.1.0