On Wed, 18 Nov 2009 05:19:06 +0100 Pavel Machek <pavel@xxxxxx> wrote: > Hi! > > > This is the second attempt to fix this problem. The first one attempted > > to fix this in procfs, but Eric Biederman pointed out that file bind > > mounts have a similar problem. This set attempts to fix the issue at a > > higher level, in the generic VFS layer. > > > > In certain situations, when it knows that they are valid, the path > > walking code will skip revalidating dentries that it finds in the cache. > > This causes problems with filesystems such as NFSv4 and CIFS that depend > > on the d_revalidate routine to do opens during lookup. > > ...and it allows bypassing directory permissions. Could we fix both > here? > Pavel Does it? Here's what I just did to check that: # cp /bin/sleep /root/sleep # ls -l /root /root/sleep dr-xr-x---. 19 root root 4096 2009-11-18 07:20 /root -rwxr-xr-x. 1 root root 29152 2009-11-18 07:20 /root/sleep # /root/sleep 600 ...then as unprivileged user: $ ps -ef | grep sleep (find pid of sleep program that root is running) $ /proc/5258/exe 600 bash: /proc/5258/exe: Permission denied ...it looks like directory permissions are respected here. Did I misunderstand what you're concerned about? -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
