Thread (4 messages) 4 messages, 3 authors, 2021-12-22
STALE1617d LANDED: 8 (8M)

[PATCH v2 1/2] asix: fix uninit-value in asix_mdio_read()

From: Pavel Skripkin <hidden>
Date: 2021-12-21 20:10:44
Also in: linux-usb, lkml
Subsystem: networking drivers, the rest, usb networking drivers · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

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 <redacted>
---

Changes in v2:
	- Added Reviewed-by tag

---
 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 42ba4af68090..06823d7141b6 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
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