diff options
| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2017-01-10 21:30:21 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-27 15:08:03 -0700 |
| commit | fee760fc6c79998efc48bd06afeec31824dfb2d4 (patch) | |
| tree | 835dacef044d32652e52696501aea9b99676e59a | |
| parent | 0fb615f9cad7966267cd1904766a1b3059336f76 (diff) | |
ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials
commit 51f8f3c4e22535933ef9aecc00e9a6069e051b57 upstream.
If overlay was mounted by root then quota set for upper layer does not work
because overlay now always use mounter's credentials for operations.
Also overlay might deplete reserved space and inodes in ext4.
This patch drops capability SYS_RESOURCE from saved credentials.
This affects creation new files, whiteouts, and copy-up operations.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 1175b6b8d963 ("ovl: do operations on underlying file system in mounter's context")
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/overlayfs/super.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 0e100856c7b8..2a0148957d6a 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1146,6 +1146,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) unsigned int stacklen = 0; unsigned int i; bool remote = false; + struct cred *cred; int err; err = -ENOMEM; @@ -1309,10 +1310,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) else sb->s_d_op = &ovl_dentry_operations; - ufs->creator_cred = prepare_creds(); - if (!ufs->creator_cred) + ufs->creator_cred = cred = prepare_creds(); + if (!cred) goto out_put_lower_mnt; + /* Never override disk quota limits or use reserved space */ + cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); + err = -ENOMEM; oe = ovl_alloc_entry(numlower); if (!oe) |