[PATCH] rose: correct integer overflow check

Since rose_ndevs is signed integer type,
it can be overflowed when it is negative.

Signed-off-by: Insu Yun <redacted>
---
 net/rose/af_rose.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 129d357..4f37fae 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c

@@ -1514,7 +1514,8 @@ static int __init rose_proto_init(void)
 	int i;
 	int rc;
 
-	if (rose_ndevs > 0x7FFFFFFF/sizeof(struct net_device *)) {
+	if (rose_ndevs < 0 ||
+	    rose_ndevs > 0x7FFFFFFF / sizeof(struct net_device *)) {
 		printk(KERN_ERR "ROSE: rose_proto_init - rose_ndevs parameter to large\n");
 		rc = -EINVAL;
 		goto out;

-- 
1.9.1

From: Insu Yun <redacted>
Date: Wed, 17 Feb 2016 15:25:13 -0500

Since rose_ndevs is signed integer type,
it can be overflowed when it is negative.

Signed-off-by: Insu Yun <redacted>

That's not how the expression is evaluated.

Because of the types on the right hand side of the comparison
the expressions are all promoted to unsigned.

Did you look at the compiler's assembler output?  I did when
reviewing your patch.