[PATCH 3.18 05/36] net: dont call strlen on non-terminated string in dev_set_alias()

From: Greg Kroah-Hartman
Date: Mon Jul 03 2017 - 11:12:37 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alexander Potapenko <glider@xxxxxxxxxx>


[ Upstream commit c28294b941232931fbd714099798eb7aa7e865d7 ]

KMSAN reported a use of uninitialized memory in dev_set_alias(),
which was caused by calling strlcpy() (which in turn called strlen())
on the user-supplied non-terminated string.

Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1194,8 +1194,9 @@ int dev_set_alias(struct net_device *dev
if (!new_ifalias)
return -ENOMEM;
dev->ifalias = new_ifalias;
+ memcpy(dev->ifalias, alias, len);
+ dev->ifalias[len] = 0;

- strlcpy(dev->ifalias, alias, len+1);
return len;
}