Commit 7e96c1b0 authored by Eric W. Biederman's avatar Eric W. Biederman

mnt: Fix fs_fully_visible to verify the root directory is visible

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: default avatarEric Windisch <ewindisch@docker.com>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent b787f68c
...@@ -3179,6 +3179,12 @@ bool fs_fully_visible(struct file_system_type *type) ...@@ -3179,6 +3179,12 @@ bool fs_fully_visible(struct file_system_type *type)
if (mnt->mnt.mnt_sb->s_type != type) if (mnt->mnt.mnt_sb->s_type != type)
continue; 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 /* This mount is not fully visible if there are any child mounts
* that cover anything except for empty directories. * that cover anything except for empty directories.
*/ */
......
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