diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2017-09-18 17:58:08 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2018-05-24 12:02:25 -0500 |
| commit | bc6155d1326092f4c29fe05a32b614249620d88e (patch) | |
| tree | d36853f7e280a4dff8d653981ce71193218c77b7 | |
| parent | 0031181c49ca94b14b11f08e447f40c6ebc842a4 (diff) | |
| download | linux-bc6155d1326092f4c29fe05a32b614249620d88e.tar.gz linux-bc6155d1326092f4c29fe05a32b614249620d88e.tar.bz2 linux-bc6155d1326092f4c29fe05a32b614249620d88e.zip | |
fs: Allow superblock owner to access do_remount_sb()
Superblock level remounts are currently restricted to global
CAP_SYS_ADMIN, as is the path for changing the root mount to
read only on umount. Loosen both of these permission checks to
also allow CAP_SYS_ADMIN in any namespace which is privileged
towards the userns which originally mounted the filesystem.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| -rw-r--r-- | fs/namespace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 5f75969adff1..8ddd14806799 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1590,7 +1590,7 @@ static int do_umount(struct mount *mnt, int flags) * Special case for "unmounting" root ... * we just try to remount it readonly. */ - if (!capable(CAP_SYS_ADMIN)) + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) return -EPERM; down_write(&sb->s_umount); if (!sb_rdonly(sb)) @@ -2333,7 +2333,7 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags, down_write(&sb->s_umount); if (ms_flags & MS_BIND) err = change_mount_flags(path->mnt, ms_flags); - else if (!capable(CAP_SYS_ADMIN)) + else if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) err = -EPERM; else err = do_remount_sb(sb, sb_flags, data, 0); |