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authorChristian Brauner <christian.brauner@ubuntu.com>2021-01-21 14:19:24 +0100
committerChristian Brauner <christian.brauner@ubuntu.com>2021-01-24 14:27:16 +0100
commit47291baa8ddfdae10663624ff0a15ab165952708 (patch)
tree132a9486b82c5eada1c4b375f693522f0a04d629 /fs/posix_acl.c
parent0558c1bf5a0811bf5e3753eed911a15b9bd08271 (diff)
namei: make permission helpers idmapped mount aware
The two helpers inode_permission() and generic_permission() are used by the vfs to perform basic permission checking by verifying that the caller is privileged over an inode. In order to handle idmapped mounts we extend the two helpers with an additional user namespace argument. On idmapped mounts the two helpers will make sure to map the inode according to the mount's user namespace and then peform identical permission checks to inode_permission() and generic_permission(). If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Diffstat (limited to 'fs/posix_acl.c')
-rw-r--r--fs/posix_acl.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 4ca6d53c6f0a..5d9fe2fb2953 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -345,10 +345,13 @@ EXPORT_SYMBOL(posix_acl_from_mode);
* by the acl. Returns -E... otherwise.
*/
int
-posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
+posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode,
+ const struct posix_acl *acl, int want)
{
const struct posix_acl_entry *pa, *pe, *mask_obj;
int found = 0;
+ kuid_t uid;
+ kgid_t gid;
want &= MAY_READ | MAY_WRITE | MAY_EXEC;
@@ -356,22 +359,26 @@ posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
switch(pa->e_tag) {
case ACL_USER_OBJ:
/* (May have been checked already) */
- if (uid_eq(inode->i_uid, current_fsuid()))
+ uid = i_uid_into_mnt(mnt_userns, inode);
+ if (uid_eq(uid, current_fsuid()))
goto check_perm;
break;
case ACL_USER:
- if (uid_eq(pa->e_uid, current_fsuid()))
+ uid = kuid_into_mnt(mnt_userns, pa->e_uid);
+ if (uid_eq(uid, current_fsuid()))
goto mask;
break;
case ACL_GROUP_OBJ:
- if (in_group_p(inode->i_gid)) {
+ gid = i_gid_into_mnt(mnt_userns, inode);
+ if (in_group_p(gid)) {
found = 1;
if ((pa->e_perm & want) == want)
goto mask;
}
break;
case ACL_GROUP:
- if (in_group_p(pa->e_gid)) {
+ gid = kgid_into_mnt(mnt_userns, pa->e_gid);
+ if (in_group_p(gid)) {
found = 1;
if ((pa->e_perm & want) == want)
goto mask;