From 144e6ce1679a768e987230efb4afa402a5ab58ac Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 17 Jan 2013 14:45:33 +0000 Subject: [PATCH] iproute2: Don't propogate mounts out of ip MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some systems are now following the advice in linux/Documentation/sharedsubtrees.txt and running with all mount points shared between all mount namespaces by default. After creating the mount namespace call mount on / with MS_SLAVE|MS_REC to modify all mounts in the new mount namespace to slave mounts if they are shared or private mounts otherwise. Guarnateeing that changes to the mount namespace created with "ip netns exec" don't propgate to other namespaces. Reported-by: Petr Šabata Tested-by: Petr Šabata Signed-off-by: "Eric W. Biederman" Signed-off-by: Petr Šabata --- ip/ipnetns.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/ip/ipnetns.c b/ip/ipnetns.c index e41a598..f2c42ba 100644 --- a/ip/ipnetns.c +++ b/ip/ipnetns.c @@ -152,6 +152,12 @@ static int netns_exec(int argc, char **argv) fprintf(stderr, "unshare failed: %s\n", strerror(errno)); return -1; } + /* Don't let any mounts propogate back to the parent */ + if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) { + fprintf(stderr, "mount --make-rslave / failed: %s\n", + strerror(errno)); + return -1; + } /* Mount a version of /sys that describes the network namespace */ if (umount2("/sys", MNT_DETACH) < 0) { fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno)); -- 1.8.1