[PATCH 5.15 042/128] asix: fix uninit-value in asix_mdio_read()

Greg Kroah-Hartman
2021-12-27T15:48:49Z

From: Pavel Skripkin <paskripkin@gmail.com>

[ Upstream commit 8035b1a2a37a29d8c717ef84fca8fe7278bc9f03 ]

asix_read_cmd() may read less than sizeof(smsr) bytes and in this case
smsr will be uninitialized.

Fail log:
BUG: KMSAN: uninit-value in asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline]
BUG: KMSAN: uninit-value in asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] drivers/net/usb/asix_common.c:497
BUG: KMSAN: uninit-value in asix_mdio_read+0x3c1/0xb00 drivers/net/usb/asix_common.c:497 drivers/net/usb/asix_common.c:497
asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline]
asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] drivers/net/usb/asix_common.c:497
asix_mdio_read+0x3c1/0xb00 drivers/net/usb/asix_common.c:497 drivers/net/usb/asix_common.c:497

Fixes: d9fe64e51114 ("net: asix: Add in_pm parameter")
Reported-and-tested-by: syzbot+f44badb06036334e867a@syzkaller.appspotmail.com
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/8966e3b514edf39857dd93603fc79ec02e000a75.1640117288.git.paskripkin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/asix_common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 38cda590895cc..b80c2dcfc9084 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -77,7 +77,7 @@ static int asix_check_host_enable(struct usbnet *dev, int in_pm)
0, 0, 1, &smsr, in_pm);
if (ret == -ENODEV)
break;
- else if (ret < 0)
+ else if (ret < sizeof(smsr))
continue;
else if (smsr & AX_HOST_EN)
break;
--
2.34.1