From: Phil Sutter <phil@nwl.cc>
Date: Wed, 13 Jun 2018 17:18:24 +0000 (+0200)
Subject: libnftables: Fix exit_cookie()
X-Git-Tag: v0.9.1~384
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5ca7ad252366865225d5c59d297e71215b68f027;p=thirdparty%2Fnftables.git

libnftables: Fix exit_cookie()

The output and error buffer feature depends on cookie->orig_fp to
indicate the current status of buffering: If it is set, a prior call to
init_cookie() is assumed. Though exit_cookie() missed to reset that
pointer to NULL. causing weird behaviour in applications if they do:

| nft = nft_ctx_new(0);
| nft_ctx_buffer_output(nft);
| nft_ctx_unbuffer_output(nft);
| nft_ctx_buffer_output(nft);

While being at it, apply the same fix to error path in init_cookie() as
well.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/src/libnftables.c b/src/libnftables.c
index 5bc7ba0d..dda986ca 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -198,6 +198,7 @@ static int init_cookie(struct cookie *cookie)
 	cookie->fp = fopencookie(cookie, "w", cookie_fops);
 	if (!cookie->fp) {
 		cookie->fp = cookie->orig_fp;
+		cookie->orig_fp = NULL;
 		return 1;
 	}
 
@@ -211,6 +212,7 @@ static int exit_cookie(struct cookie *cookie)
 
 	fclose(cookie->fp);
 	cookie->fp = cookie->orig_fp;
+	cookie->orig_fp = NULL;
 	free(cookie->buf);
 	cookie->buf = NULL;
 	cookie->buflen = 0;