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| author |   Eric W. Biederman <ebiederm@xmission.com> | 2017-11-29 17:29:20 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2017-11-30 17:47:20 -0600 |
| commit | bbc3e471011417598e598707486f5d8814ec9c01 (patch) | |
| tree | 4a1d964a20a97ab29cb0341035d4b94e77cd15a6 /fs/namei.c | |
| parent | Linux 4.15-rc1 (diff) | |
| download | linux-dev-bbc3e471011417598e598707486f5d8814ec9c01.tar.xz linux-dev-bbc3e471011417598e598707486f5d8814ec9c01.zip | |
userns: Don't fail follow_automount based on s_user_ns
When vfs_submount was added the test to limit automounts from
filesystems that with s_user_ns != &init_user_ns accidentially left
in follow_automount. The test was never about any security concerns
and was always about how do we implement this for filesystems whose
s_user_ns != &init_user_ns.
At the moment this check makes no difference as there are no
filesystems that both set FS_USERNS_MOUNT and implement d_automount.
Remove this check now while I am thinking about it so there will not
be odd booby traps for someone who does want to make this combination
work.
vfs_submount still needs improvements to allow this combination to work,
and vfs_submount contains a check that presents a warning.
The autofs4 filesystem could be modified to set FS_USERNS_MOUNT and it would
need not work on this code path, as userspace performs the mounts.
Fixes: 93faccbbfa95 ("fs: Better permission checking for submounts")
Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds")
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/namei.c b/fs/namei.c index f0c7a7b9b6ca..f47118ed36e7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1142,9 +1142,6 @@ static int follow_automount(struct path *path, struct nameidata *nd, return -ENOENT; } - if (path->dentry->d_sb->s_user_ns != &init_user_ns) - return -EACCES; - nd->total_link_count++; if (nd->total_link_count >= 40) return -ELOOP; |