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fs: use low-level mapping helpers 

In a few places the vfs needs to interact with bare k{g,u}ids directly
instead of struct inode. These are just a few. In previous patches we
introduced low-level mapping helpers that are able to support
filesystems mounted an idmapping. This patch simply converts the places
to use these new helpers.

Link: https://lore.kernel.org/r/20211123114227.3124056-7-brauner@kernel.org (v1)
Link: https://lore.kernel.org/r/20211130121032.3753852-7-brauner@kernel.org (v2)
Link: https://lore.kernel.org/r/20211203111707.3901969-7-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner 2021-12-03 12:17:03 +01:00
parent 8cc5c54de4
commit 4472071331
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
5 changed files with 24 additions and 31 deletions
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18
fs/ksmbd/smbacl.c
View File

@ -275,14 +275,7 @@ static int sid_to_id(struct user_namespace *user_ns,
uid_t id;
id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
/*
* Translate raw sid into kuid in the server's user
* namespace.
*/
uid = make_kuid(&init_user_ns, id);
/* If this is an idmapped mount, apply the idmapping. */
uid = kuid_from_mnt(user_ns, uid);
uid = mapped_kuid_user(user_ns, &init_user_ns, KUIDT_INIT(id));
if (uid_valid(uid)) {
fattr->cf_uid = uid;
rc = 0;
@ -292,14 +285,7 @@ static int sid_to_id(struct user_namespace *user_ns,
gid_t id;
id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
/*
* Translate raw sid into kgid in the server's user
* namespace.
*/
gid = make_kgid(&init_user_ns, id);
/* If this is an idmapped mount, apply the idmapping. */
gid = kgid_from_mnt(user_ns, gid);
gid = mapped_kgid_user(user_ns, &init_user_ns, KGIDT_INIT(id));
if (gid_valid(gid)) {
fattr->cf_gid = gid;
rc = 0;

4
fs/ksmbd/smbacl.h
View File

@ -217,7 +217,7 @@ static inline uid_t posix_acl_uid_translate(struct user_namespace *mnt_userns,
kuid_t kuid;
/* If this is an idmapped mount, apply the idmapping. */
kuid = kuid_into_mnt(mnt_userns, pace->e_uid);
kuid = mapped_kuid_fs(mnt_userns, &init_user_ns, pace->e_uid);
/* Translate the kuid into a userspace id ksmbd would see. */
return from_kuid(&init_user_ns, kuid);
@ -229,7 +229,7 @@ static inline gid_t posix_acl_gid_translate(struct user_namespace *mnt_userns,
kgid_t kgid;
/* If this is an idmapped mount, apply the idmapping. */
kgid = kgid_into_mnt(mnt_userns, pace->e_gid);
kgid = mapped_kgid_fs(mnt_userns, &init_user_ns, pace->e_gid);
/* Translate the kgid into a userspace id ksmbd would see. */
return from_kgid(&init_user_ns, kgid);

4
fs/open.c
View File

@ -653,8 +653,8 @@ int chown_common(const struct path *path, uid_t user, gid_t group)
gid = make_kgid(current_user_ns(), group);
mnt_userns = mnt_user_ns(path->mnt);
uid = kuid_from_mnt(mnt_userns, uid);
gid = kgid_from_mnt(mnt_userns, gid);
uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid);
gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid);
retry_deleg:
newattrs.ia_valid = ATTR_CTIME;

16
fs/posix_acl.c
View File

@ -375,7 +375,9 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode,
goto check_perm;
break;
case ACL_USER:
uid = kuid_into_mnt(mnt_userns, pa->e_uid);
uid = mapped_kuid_fs(mnt_userns,
&init_user_ns,
pa->e_uid);
if (uid_eq(uid, current_fsuid()))
goto mask;
break;
@ -388,7 +390,9 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode,
}
break;
case ACL_GROUP:
gid = kgid_into_mnt(mnt_userns, pa->e_gid);
gid = mapped_kgid_fs(mnt_userns,
&init_user_ns,
pa->e_gid);
if (in_group_p(gid)) {
found = 1;
if ((pa->e_perm & want) == want)
@ -735,17 +739,17 @@ static void posix_acl_fix_xattr_userns(
case ACL_USER:
uid = make_kuid(from, le32_to_cpu(entry->e_id));
if (from_user)
uid = kuid_from_mnt(mnt_userns, uid);
uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid);
else
uid = kuid_into_mnt(mnt_userns, uid);
uid = mapped_kuid_fs(mnt_userns, &init_user_ns, uid);
entry->e_id = cpu_to_le32(from_kuid(to, uid));
break;
case ACL_GROUP:
gid = make_kgid(from, le32_to_cpu(entry->e_id));
if (from_user)
gid = kgid_from_mnt(mnt_userns, gid);
gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid);
else
gid = kgid_into_mnt(mnt_userns, gid);
gid = mapped_kgid_fs(mnt_userns, &init_user_ns, gid);
entry->e_id = cpu_to_le32(from_kgid(to, gid));
break;
default:

13
security/commoncap.c
View File

@ -419,7 +419,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns,
kroot = make_kuid(fs_ns, root);
/* If this is an idmapped mount shift the kuid. */
kroot = kuid_into_mnt(mnt_userns, kroot);
kroot = mapped_kuid_fs(mnt_userns, &init_user_ns, kroot);
/* If the root kuid maps to a valid uid in current ns, then return
* this as a nscap. */
@ -489,6 +489,7 @@ out_free:
* @size: size of @ivalue
* @task_ns: user namespace of the caller
* @mnt_userns: user namespace of the mount the inode was found from
* @fs_userns: user namespace of the filesystem
*
* If the inode has been found through an idmapped mount the user namespace of
* the vfsmount must be passed through @mnt_userns. This function will then
@ -498,7 +499,8 @@ out_free:
*/
static kuid_t rootid_from_xattr(const void *value, size_t size,
struct user_namespace *task_ns,
struct user_namespace *mnt_userns)
struct user_namespace *mnt_userns,
struct user_namespace *fs_userns)
{
const struct vfs_ns_cap_data *nscap = value;
kuid_t rootkid;
@ -508,7 +510,7 @@ static kuid_t rootid_from_xattr(const void *value, size_t size,
rootid = le32_to_cpu(nscap->rootid);
rootkid = make_kuid(task_ns, rootid);
return kuid_from_mnt(mnt_userns, rootkid);
return mapped_kuid_user(mnt_userns, fs_userns, rootkid);
}
static bool validheader(size_t size, const struct vfs_cap_data *cap)
@ -559,7 +561,8 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry,
/* user is privileged, just write the v2 */
return size;
rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns);
rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns,
&init_user_ns);
if (!uid_valid(rootid))
return -EINVAL;
@ -700,7 +703,7 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns,
/* Limit the caps to the mounter of the filesystem
* or the more limited uid specified in the xattr.
*/
rootkuid = kuid_into_mnt(mnt_userns, rootkuid);
rootkuid = mapped_kuid_fs(mnt_userns, &init_user_ns, rootkuid);
if (!rootid_owns_currentns(rootkuid))
return -ENODATA;