[v3,11/25] inode: inode_owner_or_capable(): handle fsid mappings

Submitted by Christian Brauner on Feb. 18, 2020, 2:33 p.m.

Details

Message ID 20200218143411.2389182-12-christian.brauner@ubuntu.com
State New
Series "user_namespace: introduce fsid mappings"
Headers show

Commit Message

Christian Brauner Feb. 18, 2020, 2:33 p.m.
Switch inode_owner_or_capable() to lookup fsids in the fsid mappings. If no
fsid mappings are setup the behavior is unchanged, i.e. fsids are looked up in
the id mappings.

Filesystems that share a superblock in all user namespaces they are mounted in
will retain their old semantics even with the introduction of fsid mappings.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
unchanged

/* v3 */
unchanged
---
 fs/inode.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Patch hide | download patch | download mbox

diff --git a/fs/inode.c b/fs/inode.c
index 7d57068b6b7a..81d7a30b381d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -21,6 +21,7 @@ 
 #include <linux/ratelimit.h>
 #include <linux/list_lru.h>
 #include <linux/iversion.h>
+#include <linux/fsuidgid.h>
 #include <trace/events/writeback.h>
 #include "internal.h"
 
@@ -2087,8 +2088,12 @@  bool inode_owner_or_capable(const struct inode *inode)
 		return true;
 
 	ns = current_user_ns();
-	if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
+	if (is_userns_visible(inode->i_sb->s_iflags)) {
+		if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
+			return true;
+	} else if (kfsuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER)) {
 		return true;
+	}
 	return false;
 }
 EXPORT_SYMBOL(inode_owner_or_capable);

Comments

Christoph Hellwig Feb. 18, 2020, 10:25 p.m.
On Tue, Feb 18, 2020 at 03:33:57PM +0100, Christian Brauner wrote:
> +	if (is_userns_visible(inode->i_sb->s_iflags)) {
> +		if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
> +			return true;
> +	} else if (kfsuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER)) {

This adds some crazy long unreadable lines..
Christian Brauner Feb. 19, 2020, 12:29 p.m.
On Tue, Feb 18, 2020 at 02:25:23PM -0800, Christoph Hellwig wrote:
> On Tue, Feb 18, 2020 at 03:33:57PM +0100, Christian Brauner wrote:
> > +	if (is_userns_visible(inode->i_sb->s_iflags)) {
> > +		if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
> > +			return true;
> > +	} else if (kfsuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER)) {
> 
> This adds some crazy long unreadable lines..

I'll ad a helper in the next version or wrap those lines depending on
what makes more sense.