netdev - [PATCH iproute2-3.8 1/6] iproute2: Don't propogate mounts out of ip

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87y5fr48uq.fsf_-_@xmission.com>
Date:	Thu, 17 Jan 2013 16:45:33 -0800
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Stephen Hemminger <shemminger@...tta.com>
Cc:	<netdev@...r.kernel.org>, "Serge E. Hallyn" <serge@...lyn.com>,
	Ben Hutchings <bhutchings@...arflare.com>,
	Petr Šabata <contyk@...hat.com>
Subject: [PATCH iproute2-3.8 1/6] iproute2: Don't propogate mounts out of ip


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 <contyk@...hat.com>
Tested-by: Petr Šabata <contyk@...hat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 ip/ipnetns.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

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));
-- 
1.7.5.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html