[PATCH v2 21/28] posix_acl: handle fsid mappings

Christian Brauner
2020-02-14T18:41:14Z

Switch posix_acls() 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.

Afaict, all filesystems that share a superblock in all user namespaces
currently do not support acls so this change should be safe to do
unconditionally.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
unchanged
---
fs/posix_acl.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 249672bf54fe..763bba24f380 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -22,6 +22,7 @@
#include <linux/xattr.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
+#include <linux/fsuidgid.h>

static struct posix_acl **acl_by_type(struct inode *inode, int type)
{
@@ -692,12 +693,12 @@ static void posix_acl_fix_xattr_userns(
for (end = entry + count; entry != end; entry++) {
switch(le16_to_cpu(entry->e_tag)) {
case ACL_USER:
- uid = make_kuid(from, le32_to_cpu(entry->e_id));
- entry->e_id = cpu_to_le32(from_kuid(to, uid));
+ uid = make_kfsuid(from, le32_to_cpu(entry->e_id));
+ entry->e_id = cpu_to_le32(from_kfsuid(to, uid));
break;
case ACL_GROUP:
- gid = make_kgid(from, le32_to_cpu(entry->e_id));
- entry->e_id = cpu_to_le32(from_kgid(to, gid));
+ gid = make_kfsgid(from, le32_to_cpu(entry->e_id));
+ entry->e_id = cpu_to_le32(from_kfsgid(to, gid));
break;
default:
break;
@@ -746,12 +747,12 @@ posix_acl_from_xattr(struct user_namespace *user_ns,
return ERR_PTR(-EINVAL);
if (count == 0)
return NULL;
-
+
acl = posix_acl_alloc(count, GFP_NOFS);
if (!acl)
return ERR_PTR(-ENOMEM);
acl_e = acl->a_entries;
-
+
for (end = entry + count; entry != end; acl_e++, entry++) {
acl_e->e_tag = le16_to_cpu(entry->e_tag);
acl_e->e_perm = le16_to_cpu(entry->e_perm);
@@ -765,14 +766,14 @@ posix_acl_from_xattr(struct user_namespace *user_ns,

case ACL_USER:
acl_e->e_uid =
- make_kuid(user_ns,
+ make_kfsuid(user_ns,
le32_to_cpu(entry->e_id));
if (!uid_valid(acl_e->e_uid))
goto fail;
break;
case ACL_GROUP:
acl_e->e_gid =
- make_kgid(user_ns,
+ make_kfsgid(user_ns,
le32_to_cpu(entry->e_id));
if (!gid_valid(acl_e->e_gid))
goto fail;
@@ -817,11 +818,11 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
switch(acl_e->e_tag) {
case ACL_USER:
ext_entry->e_id =
- cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
+ cpu_to_le32(from_kfsuid(user_ns, acl_e->e_uid));
break;
case ACL_GROUP:
ext_entry->e_id =
- cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
+ cpu_to_le32(from_kfsgid(user_ns, acl_e->e_gid));
break;
default:
ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
--
2.25.0