Unverified Commit b7c9b675 authored by Christian Brauner's avatar Christian Brauner Committed by Christian Brauner (Microsoft)
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caps: use type safe idmapping helpers 



We already ported most parts and filesystems over for v6.0 to the new
vfs{g,u}id_t type and associated helpers for v6.0. Convert the remaining
places so we can remove all the old helpers.
This is a non-functional change.

Reviewed-by: default avatarSeth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
parent a2bd096f

kernel/capability.c

+2 −2
Original line number Diff line number Diff line
@@ -489,8 +489,8 @@ bool privileged_wrt_inode_uidgid(struct user_namespace *ns, 
				 struct user_namespace *mnt_userns,

				 const struct inode *inode)

{

	return kuid_has_mapping(ns, i_uid_into_mnt(mnt_userns, inode)) &&

	       kgid_has_mapping(ns, i_gid_into_mnt(mnt_userns, inode));

	return vfsuid_has_mapping(ns, i_uid_into_vfsuid(mnt_userns, inode)) &&

	       vfsgid_has_mapping(ns, i_gid_into_vfsgid(mnt_userns, inode));

}



/**

security/commoncap.c

+26 −25
Original line number Diff line number Diff line
@@ -328,13 +328,15 @@ int cap_inode_killpriv(struct user_namespace *mnt_userns, struct dentry *dentry) 
	return error;

}



static bool rootid_owns_currentns(kuid_t kroot)

static bool rootid_owns_currentns(vfsuid_t rootvfsuid)

{

	struct user_namespace *ns;

	kuid_t kroot;



	if (!uid_valid(kroot))

	if (!vfsuid_valid(rootvfsuid))

		return false;



	kroot = vfsuid_into_kuid(rootvfsuid);

	for (ns = current_user_ns();; ns = ns->parent) {

		if (from_kuid(ns, kroot) == 0)

			return true;
@@ -381,6 +383,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, 
{

	int size, ret;

	kuid_t kroot;

	vfsuid_t vfsroot;

	u32 nsmagic, magic;

	uid_t root, mappedroot;

	char *tmpbuf = NULL;
@@ -419,11 +422,11 @@ 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 = mapped_kuid_fs(mnt_userns, fs_ns, kroot);

	vfsroot = make_vfsuid(mnt_userns, fs_ns, kroot);



	/* If the root kuid maps to a valid uid in current ns, then return

	 * this as a nscap. */

	mappedroot = from_kuid(current_user_ns(), kroot);

	mappedroot = from_kuid(current_user_ns(), vfsuid_into_kuid(vfsroot));

	if (mappedroot != (uid_t)-1 && mappedroot != (uid_t)0) {

		size = sizeof(struct vfs_ns_cap_data);

		if (alloc) {
@@ -450,7 +453,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, 
		goto out_free;

	}



	if (!rootid_owns_currentns(kroot)) {

	if (!rootid_owns_currentns(vfsroot)) {

		size = -EOVERFLOW;

		goto out_free;

	}
@@ -488,29 +491,17 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, 
 * @value:	vfs caps value which may be modified by this function

 * @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

 * take care to map the inode according to @mnt_userns before checking

 * permissions. On non-idmapped mounts or if permission checking is to be

 * performed on the raw inode simply passs init_user_ns.

 */

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 *fs_userns)

static vfsuid_t rootid_from_xattr(const void *value, size_t size,

				  struct user_namespace *task_ns)

{

	const struct vfs_ns_cap_data *nscap = value;

	kuid_t rootkid;

	uid_t rootid = 0;



	if (size == XATTR_CAPS_SZ_3)

		rootid = le32_to_cpu(nscap->rootid);



	rootkid = make_kuid(task_ns, rootid);

	return mapped_kuid_user(mnt_userns, fs_userns, rootkid);

	return VFSUIDT_INIT(make_kuid(task_ns, rootid));

}



static bool validheader(size_t size, const struct vfs_cap_data *cap)
@@ -548,6 +539,7 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry, 
	struct user_namespace *task_ns = current_user_ns(),

		*fs_ns = inode->i_sb->s_user_ns;

	kuid_t rootid;

	vfsuid_t vfsrootid;

	size_t newsize;



	if (!*ivalue)
@@ -561,7 +553,11 @@ 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, fs_ns);

	vfsrootid = rootid_from_xattr(*ivalue, size, task_ns);

	if (!vfsuid_valid(vfsrootid))

		return -EINVAL;



	rootid = from_vfsuid(mnt_userns, fs_ns, vfsrootid);

	if (!uid_valid(rootid))

		return -EINVAL;
@@ -655,6 +651,7 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, 
	struct vfs_ns_cap_data data, *nscaps = &data;

	struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;

	kuid_t rootkuid;

	vfsuid_t rootvfsuid;

	struct user_namespace *fs_ns;



	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
@@ -699,11 +696,15 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, 
	default:

		return -EINVAL;

	}



	rootvfsuid = make_vfsuid(mnt_userns, fs_ns, rootkuid);

	if (!vfsuid_valid(rootvfsuid))

		return -ENODATA;



	/* Limit the caps to the mounter of the filesystem

	 * or the more limited uid specified in the xattr.

	 */

	rootkuid = mapped_kuid_fs(mnt_userns, fs_ns, rootkuid);

	if (!rootid_owns_currentns(rootkuid))

	if (!rootid_owns_currentns(rootvfsuid))

		return -ENODATA;



	CAP_FOR_EACH_U32(i) {
@@ -716,7 +717,7 @@ int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, 
	cpu_caps->permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;

	cpu_caps->inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;



	cpu_caps->rootid = rootkuid;

	cpu_caps->rootid = vfsuid_into_kuid(rootvfsuid);



	return 0;

}