[net-next] tipc: do sanity check payload of a netlink message

* [net-next] tipc: do sanity check payload of a netlink message
@ 2020-12-15  3:31 Hoang Huu Le
  2020-12-16 21:10 ` patchwork-bot+netdevbpf
  0 siblings, 1 reply; 2+ messages in thread
From: Hoang Huu Le @ 2020-12-15  3:31 UTC (permalink / raw)
  To: jmaloy, maloy, ying.xue, netdev; +Cc: Hoang Le

From: Hoang Le <hoang.h.le@dektech.com.au>

When we initialize nlmsghdr with no payload inside tipc_nl_compat_dumpit()
the parsing function returns -EINVAL. We fix it by making the parsing call
conditional.

Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
---
 net/tipc/netlink_compat.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index 82f154989418..5a1ce64039f7 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -213,12 +213,14 @@ static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
 	}
 
 	info.attrs = attrbuf;
-	err = nlmsg_parse_deprecated(cb.nlh, GENL_HDRLEN, attrbuf,
-				     tipc_genl_family.maxattr,
-				     tipc_genl_family.policy, NULL);
-	if (err)
-		goto err_out;
 
+	if (nlmsg_len(cb.nlh) > 0) {
+		err = nlmsg_parse_deprecated(cb.nlh, GENL_HDRLEN, attrbuf,
+					     tipc_genl_family.maxattr,
+					     tipc_genl_family.policy, NULL);
+		if (err)
+			goto err_out;
+	}
 	do {
 		int rem;
 
-- 
2.25.1


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