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| author | Eric W. Biederman <ebiederm@xmission.com> | 2017-11-30 02:29:20 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-19 10:42:50 +0300 |
| commit | 5aac93adff9caa5920af52ea1db2a5dc2c1badd9 (patch) | |
| tree | cf8a87115d53b5394bb470791295553c074a4bc8 /fs/namei.c | |
| parent | 926b261b1ed523f2e64dfcf33eafc59e0af5bcb4 (diff) | |
| download | linux-5aac93adff9caa5920af52ea1db2a5dc2c1badd9.tar.xz | |
userns: Don't fail follow_automount based on s_user_ns
[ Upstream commit bbc3e471011417598e598707486f5d8814ec9c01 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 62a0db6e6725..cbe24e367a70 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1133,9 +1133,6 @@ static int follow_automount(struct path *path, struct nameidata *nd, path->dentry->d_inode) return -EISDIR; - 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; |