2018-03-23 12:51:10

by Alexander Potapenko

Subject: [PATCH] netlink: make sure nladdr has correct size in netlink_connect()

KMSAN reports use of uninitialized memory in the case when |alen| is
smaller than sizeof(struct sockaddr_nl), and therefore |nladdr| isn't
fully copied from the userspace.

Signed-off-by: Alexander Potapenko <[email protected]>
Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")
---
v2: fixed a typo spotted by Eric Dumazet
---
net/netlink/af_netlink.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 07e8478068f0..70c455341243 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
if (addr->sa_family != AF_NETLINK)
return -EINVAL;

+ if (alen < sizeof(struct sockaddr_nl))
+ return -EINVAL;
+
if ((nladdr->nl_groups || nladdr->nl_pid) &&
!netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
return -EPERM;
--
2.17.0.rc0.231.g781580f067-goog

2018-03-23 12:58:54

by Eric Dumazet

Subject: Re: [PATCH] netlink: make sure nladdr has correct size in netlink_connect()

On 03/23/2018 05:49 AM, Alexander Potapenko wrote:
> KMSAN reports use of uninitialized memory in the case when |alen| is
> smaller than sizeof(struct sockaddr_nl), and therefore |nladdr| isn't
> fully copied from the userspace.
>
> Signed-off-by: Alexander Potapenko <[email protected]>
> Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")

Reviewed-by: Eric Dumazet <[email protected]>

Thanks Alexander.

2018-03-26 01:18:25

by David Miller

Subject: Re: [PATCH] netlink: make sure nladdr has correct size in netlink_connect()

From: Alexander Potapenko <[email protected]>
Date: Fri, 23 Mar 2018 13:49:02 +0100

> KMSAN reports use of uninitialized memory in the case when |alen| is
> smaller than sizeof(struct sockaddr_nl), and therefore |nladdr| isn't
> fully copied from the userspace.
>
> Signed-off-by: Alexander Potapenko <[email protected]>
> Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")
> ---
> v2: fixed a typo spotted by Eric Dumazet

Applied and queued up for -stable, thank you.