[PATCH net] ax25: uninitialized variable in ax25_setsockopt()

[PATCH net] ax25: uninitialized variable in ax25_setsockopt()

[Dan Carpenter]

The "opt" variable is unsigned long but we only copy 4 bytes from
the user so the lower 4 bytes are uninitialized.

I have changed the integer overflow checks from ULONG to UINT as well.
This is a slight API change but I don't expect it to break anything.

Fixes: a7b75c5a8c41 ("net: pass a sockptr_t into ->setsockopt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 net/ax25/af_ax25.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index cfca99e295b8..02f43f3e2c56 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -536,7 +536,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 	ax25_cb *ax25;
 	struct net_device *dev;
 	char devname[IFNAMSIZ];
-	unsigned long opt;
+	unsigned int opt;
 	int res = 0;
 
 	if (level != SOL_AX25)
@@ -568,7 +568,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T1:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -577,7 +577,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T2:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -593,7 +593,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T3:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -601,7 +601,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_IDLE:
-		if (opt > ULONG_MAX / (60 * HZ)) {
+		if (opt > UINT_MAX / (60 * HZ)) {
 			res = -EINVAL;
 			break;
 		}
-- 
2.20.1

Re: [PATCH net] ax25: uninitialized variable in ax25_setsockopt()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri, 7 Jan 2022 10:13:12 +0300 you wrote:
> The "opt" variable is unsigned long but we only copy 4 bytes from
> the user so the lower 4 bytes are uninitialized.
> 
> I have changed the integer overflow checks from ULONG to UINT as well.
> This is a slight API change but I don't expect it to break anything.
> 
> Fixes: a7b75c5a8c41 ("net: pass a sockptr_t into ->setsockopt")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> [...]

Here is the summary with links:
  - [net] ax25: uninitialized variable in ax25_setsockopt()
    https://git.kernel.org/netdev/net/c/9371937092d5

You are awesome, thank you!
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