Re: [PATCH] ipset: fix a missing check of nla_parse

On 10.01.2019 01:43, Pablo Neira Ayuso wrote:

On Wed, Dec 26, 2018 at 12:16:25PM +0300, Kirill Tkhai wrote:

quoted

On 26.12.2018 06:50, Kangjie Lu wrote:

quoted

When nla_parse fails, we should not use the results (the first
argument). The fix checks if it fails, and if so, returns its error code
upstream.

Signed-off-by: Kangjie Lu <redacted>
---
 net/netfilter/ipset/ip_set_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 1577f2f76060..4dc8057cff02 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c

@@ -1531,8 +1531,10 @@ call_ad(struct sock *ctnl, struct sk_buff *skb, struct ip_set *set,
 		memcpy(&errmsg->msg, nlh, nlh->nlmsg_len);
 		cmdattr = (void *)&errmsg->msg + min_len;
 
-		nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr,
+		ret = nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr,
 			  nlh->nlmsg_len - min_len, ip_set_adt_policy, NULL);

@Kangjie: nitpick, could you align this line below? ie.

		ret = nla_parse(cda, IPSET_ATTR_CMD_MAX, cmdattr,
                                nlh->nlmsg_len - min_len, ip_set_adt_policy,
                                NULL);

quoted

quoted

+		if (ret)
+			return ret;

In this function above nlmsg_new() allocates skb2, but I don't see, where you free it here.

netlink_unicast() is responsible for releasing this skb2.

We return earlier at "if (ret)", so netlink_unicast() is not called.
 

quoted

quoted

 		errline = nla_data(cda[IPSET_ATTR_LINENO]);

Kirill