diff mbox series

netlink: policy: correct validation type check

Message ID 20200831202805.8ca5a2fe1ffb.I46f0d5bee0a774517aeec539620895a473dd2299@changeid
State Accepted
Delegated to: David Miller
Headers show
Series netlink: policy: correct validation type check | expand

Commit Message

Johannes Berg Aug. 31, 2020, 6:28 p.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

In the policy export for binary attributes I erroneously used
a != NLA_VALIDATE_NONE comparison instead of checking for the
two possible values, which meant that if a validation function
pointer ended up aliasing the min/max as negatives, we'd hit
a warning in nla_get_range_unsigned().

Fix this to correctly check for only the two types that should
be handled here, i.e. range with or without warn-too-long.

Reported-by: syzbot+353df1490da781637624@syzkaller.appspotmail.com
Fixes: 8aa26c575fb3 ("netlink: make NLA_BINARY validation more flexible")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/netlink/policy.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

David Miller Aug. 31, 2020, 7:02 p.m. UTC | #1 
From: Johannes Berg <johannes@sipsolutions.net>
Date: Mon, 31 Aug 2020 20:28:05 +0200

> From: Johannes Berg <johannes.berg@intel.com>
> 
> In the policy export for binary attributes I erroneously used
> a != NLA_VALIDATE_NONE comparison instead of checking for the
> two possible values, which meant that if a validation function
> pointer ended up aliasing the min/max as negatives, we'd hit
> a warning in nla_get_range_unsigned().
> 
> Fix this to correctly check for only the two types that should
> be handled here, i.e. range with or without warn-too-long.
> 
> Reported-by: syzbot+353df1490da781637624@syzkaller.appspotmail.com
> Fixes: 8aa26c575fb3 ("netlink: make NLA_BINARY validation more flexible")
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Applied, thank you.
diff mbox series

Patch

diff --git a/net/netlink/policy.c b/net/netlink/policy.c
index 7b1f50531cd3..5c9e7530865f 100644
--- a/net/netlink/policy.c
+++ b/net/netlink/policy.c
@@ -264,7 +264,8 @@  int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state)
 		else
 			type = NL_ATTR_TYPE_BINARY;
 
-		if (pt->validation_type != NLA_VALIDATE_NONE) {
+		if (pt->validation_type == NLA_VALIDATE_RANGE ||
+		    pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG) {
 			struct netlink_range_validation range;
 
 			nla_get_range_unsigned(pt, &range);