From: Phil Sutter <phil@nwl.cc>
Date: Fri, 31 May 2019 14:17:42 +0000 (+0200)
Subject: mnl: Initialize fd_set before select(), not after
X-Git-Tag: v0.9.1~53
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59d301ec80264a907918028c590f7f172003a995;p=thirdparty%2Fnftables.git

mnl: Initialize fd_set before select(), not after

Calling FD_SET() in between return of select() and call to FD_ISSET()
effectively renders the whole thing useless: FD_ISSET() will always
return true no matter what select() actually did.

Fixes: a72315d2bad47 ("src: add rule batching support")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/src/mnl.c b/src/mnl.c
index 4eba27895..b32e4190b 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -349,12 +349,12 @@ int mnl_batch_talk(struct netlink_ctx *ctx, struct list_head *err_list,
 		if (ret == -1)
 			mnl_err_list_node_add(err_list, errno, nlh->nlmsg_seq);
 
+		FD_ZERO(&readfds);
+		FD_SET(fd, &readfds);
+
 		ret = select(fd+1, &readfds, NULL, NULL, &tv);
 		if (ret == -1)
 			return -1;
-
-		FD_ZERO(&readfds);
-		FD_SET(fd, &readfds);
 	}
 	return 0;
 }