From: Eric W. Biederman Date: Fri, 8 May 2015 21:36:50 +0000 (-0500) Subject: mnt: Fix fs_fully_visible to verify the root directory is visible X-Git-Tag: v3.18.15~162 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c981af6c8ed75640a7058473aaf42732386836c;p=thirdparty%2Fkernel%2Fstable.git mnt: Fix fs_fully_visible to verify the root directory is visible [ Upstream commit 7e96c1b0e0f495c5a7450dc4aa7c9a24ba4305bd ] This fixes a dumb bug in fs_fully_visible that allows proc or sys to be mounted if there is a bind mount of part of /proc/ or /sys/ visible. Cc: stable@vger.kernel.org Reported-by: Eric Windisch Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin --- diff --git a/fs/namespace.c b/fs/namespace.c index 07ba424181a55..64837e3f1a5c7 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3137,6 +3137,12 @@ bool fs_fully_visible(struct file_system_type *type) if (mnt->mnt.mnt_sb->s_type != type) continue; + /* This mount is not fully visible if it's root directory + * is not the root directory of the filesystem. + */ + if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root) + continue; + /* This mount is not fully visible if there are any child mounts * that cover anything except for empty directories. */