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netlink: make sure nladdr has correct size in netlink_connect()

PATCH In review Alexander Potapenko 3 participants 3 messages Mar 23, 2018 – Mar 26, 2018

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Networking Network drivers
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Alexander Potapenko

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#0 lore raw

PATCH 1/1 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(+)
net/netlink/af_netlink.c +3 -0
index 07e8478068f0..70c455341243 100644
@@ -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;
Signature · 1 line
2.17.0.rc0.231.g781580f067-goog
maintainer
#2 lore raw
In reply to Alexander Potapenko

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

Quoted 8 lines

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.