[PATCH 4.11 01/84] net: dont call strlen on non-terminated string in dev_set_alias()

Greg Kroah-Hartman
2017-07-03T14:08:13Z

From: Alexander Potapenko <glider@google.com>

[ 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@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/dev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1251,8 +1251,9 @@ 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;
}