[lxc-devel] [PATCH] Improper pty permissions - missing mode=0620, gid=5

[Stéphane Graber]

This fix is coming from Debian bug:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=720122

The reason for the hardcoded gid= and mode= is because of the fix for
CVE-2013-2207 which removes pt_chown from glibc and so requires proper
write access to devpts.

It looks like the "tty" group is guaranteed to be gid=5 on at least all
RedHat based and Debian based systems. So this hardcode gid shouldn't be
a big problem. If we however support any distro where that's not the
case, we'll need to implement an extra lxc.conf option and matching
template changes.

Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
---
 src/lxc/conf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index ecbcf41..f3d9aab 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1426,7 +1426,7 @@ static int setup_pts(int pts)
 	}
 
 	if (mount("devpts", "/dev/pts", "devpts", MS_MGC_VAL,
-		  "newinstance,ptmxmode=0666")) {
+		  "newinstance,ptmxmode=0666,mode=0620,gid=5")) {
 		SYSERROR("failed to mount a new instance of '/dev/pts'");
 		return -1;
 	}
-- 
1.8.3.2