From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matteo Croce Subject: [PATCH v2] netns: avoid directory traversal (was: ip netns: Make sure netns name is sane) Date: Thu, 20 Jul 2017 00:36:32 +0200 Message-ID: <20170719223632.4124-1-mcroce@redhat.com> References: <20170718171230.084c804e@xeon-e3> Cc: netdev@vger.kernel.org To: Phil Sutter Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33248 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911AbdGSWgf (ORCPT ); Wed, 19 Jul 2017 18:36:35 -0400 In-Reply-To: <20170718171230.084c804e@xeon-e3> Sender: netdev-owner@vger.kernel.org List-ID: v2: reword commit message ip netns keeps track of created namespaces with bind mounts named /var/run/netns/. No input sanitization is done, allowing creation and deletion of files relatives to /var/run/netns or, if the path is non existent or invalid, allows to create "untracked" namespaces (invisible to the tool). This commit denies creation or deletion of namespaces with names contaning "/" or matching exactly "." or "..". Signed-off-by: Matteo Croce --- ip/ipnetns.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/ip/ipnetns.c b/ip/ipnetns.c index 0b0378ab..42549944 100644 --- a/ip/ipnetns.c +++ b/ip/ipnetns.c @@ -766,6 +766,11 @@ static int netns_monitor(int argc, char **argv) return 0; } +static int invalid_name(const char *name) +{ + return strchr(name, '/') || !strcmp(name, ".") || !strcmp(name, ".."); +} + int do_netns(int argc, char **argv) { netns_nsid_socket_init(); @@ -775,6 +780,11 @@ int do_netns(int argc, char **argv) return netns_list(0, NULL); } + if (argc > 1 && invalid_name(argv[1])) { + fprintf(stderr, "Invalid netns name \"%s\"\n", argv[1]); + exit(-1); + } + if ((matches(*argv, "list") == 0) || (matches(*argv, "show") == 0) || (matches(*argv, "lst") == 0)) { netns_map_init(); -- 2.13.3