LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH] net: asix: fix uninit value in asix_mdio_read
@ 2021-08-13 16:01 Pavel Skripkin
  2021-08-13 22:23 ` Andrew Lunn
  0 siblings, 1 reply; 12+ messages in thread
From: Pavel Skripkin @ 2021-08-13 16:01 UTC (permalink / raw)
  To: davem, kuba, linux, himadrispandya, andrew
  Cc: linux-usb, netdev, linux-kernel, Pavel Skripkin,
	syzbot+a631ec9e717fb0423053

Syzbot reported uninit-value in asix_mdio_read(). The problem was in
missing error handling. asix_read_cmd() should initialize passed stack
variable smsr, but it can fail in some cases. Then while condidition
checks possibly uninit smsr variable.

Since smsr is uninitialized stack variable, driver can misbehave,
because smsr will be random in case of asix_read_cmd() failure.
Fix it by adding error cheking and just continue the loop instead of
checking uninit value.

Fixes: 8a46f665833a ("net: asix: Avoid looping when the device is disconnected")
Reported-and-tested-by: syzbot+a631ec9e717fb0423053@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/net/usb/asix_common.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index ac92bc52a85e..572ca3077f8f 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -479,7 +479,13 @@ int asix_mdio_read(struct net_device *netdev, int phy_id, int loc)
 		usleep_range(1000, 1100);
 		ret = asix_read_cmd(dev, AX_CMD_STATMNGSTS_REG,
 				    0, 0, 1, &smsr, 0);
-	} while (!(smsr & AX_HOST_EN) && (i++ < 30) && (ret != -ENODEV));
+		if (ret == -ENODEV) {
+			break;
+		} else if (ret < 0) {
+			++i;
+			continue;
+		}
+	} while (!(smsr & AX_HOST_EN) && (i++ < 30));
 	if (ret == -ENODEV || ret == -ETIMEDOUT) {
 		mutex_unlock(&dev->phy_mutex);
 		return ret;
-- 
2.32.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2021-08-18 10:50 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-13 16:01 [PATCH] net: asix: fix uninit value in asix_mdio_read Pavel Skripkin
2021-08-13 22:23 ` Andrew Lunn
2021-08-13 22:29   ` Pavel Skripkin
2021-08-13 22:42   ` [PATCH v2] " Pavel Skripkin
2021-08-13 22:52     ` Jakub Kicinski
2021-08-14 13:55       ` [PATCH v3] net: asix: fix uninit value bugs Pavel Skripkin
2021-08-14 15:36         ` Andrew Lunn
2021-08-14 15:40           ` Pavel Skripkin
2021-08-14 16:20           ` Pavel Skripkin
2021-08-17 16:37           ` [PATCH v4] " Pavel Skripkin
2021-08-18 10:50             ` patchwork-bot+netdevbpf
2021-08-13 22:57     ` [PATCH v2] net: asix: fix uninit value in asix_mdio_read Andrew Lunn

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).