[patch net-next] net: tipc: prepare attrs in __tipc_nl_compat_dumpit()

[Jiri Pirko]

From: Jiri Pirko <j...@mellanox.com>

__tipc_nl_compat_dumpit() calls tipc_nl_publ_dump() which expects
the attrs to be available by genl_dumpit_info(cb)->attrs. Add info
struct and attr parsing in compat dumpit function.

Reported-by: syzbot+8d37c50ffb0f52941...@syzkaller.appspotmail.com
Fixes: 057af7071344 ("net: tipc: have genetlink code to parse the attrs during 
dumpit")

Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 net/tipc/netlink_compat.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index 4950b754dacd..17a529739f8d 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -181,6 +181,7 @@ static int __tipc_nl_compat_dumpit(struct 
tipc_nl_compat_cmd_dump *cmd,
                                   struct tipc_nl_compat_msg *msg,
                                   struct sk_buff *arg)
 {
+       struct genl_dumpit_info info;
        int len = 0;
        int err;
        struct sk_buff *buf;
@@ -191,6 +192,7 @@ static int __tipc_nl_compat_dumpit(struct 
tipc_nl_compat_cmd_dump *cmd,
        memset(&cb, 0, sizeof(cb));
        cb.nlh = (struct nlmsghdr *)arg->data;
        cb.skb = arg;
+       cb.data = &info;
 
        buf = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!buf)
@@ -209,6 +211,13 @@ static int __tipc_nl_compat_dumpit(struct 
tipc_nl_compat_cmd_dump *cmd,
                goto err_out;
        }
 
+       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;
+
        do {
                int rem;
 
-- 
2.21.0