diff options
Diffstat (limited to 'fs/posix_acl.c')
| -rw-r--r-- | fs/posix_acl.c | 651 |
1 files changed, 497 insertions, 154 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 2fd0fde16fe1..768f027c1428 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org> * @@ -21,6 +22,14 @@ #include <linux/xattr.h> #include <linux/export.h> #include <linux/user_namespace.h> +#include <linux/namei.h> +#include <linux/mnt_idmapping.h> +#include <linux/iversion.h> +#include <linux/security.h> +#include <linux/fsnotify.h> +#include <linux/filelock.h> + +#include "internal.h" static struct posix_acl **acl_by_type(struct inode *inode, int type) { @@ -55,7 +64,17 @@ EXPORT_SYMBOL(get_cached_acl); struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) { - return rcu_dereference(*acl_by_type(inode, type)); + struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type)); + + if (acl == ACL_DONT_CACHE) { + struct posix_acl *ret; + + ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU); + if (!IS_ERR(ret)) + acl = ret; + } + + return acl; } EXPORT_SYMBOL(get_cached_acl_rcu); @@ -92,15 +111,17 @@ void forget_all_cached_acls(struct inode *inode) } EXPORT_SYMBOL(forget_all_cached_acls); -struct posix_acl *get_acl(struct inode *inode, int type) +static struct posix_acl *__get_acl(struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + int type) { - void *sentinel; + struct posix_acl *sentinel; struct posix_acl **p; struct posix_acl *acl; /* * The sentinel is used to detect when another operation like - * set_cached_acl() or forget_cached_acl() races with get_acl(). + * set_cached_acl() or forget_cached_acl() races with get_inode_acl(). * It is guaranteed that is_uncached_acl(sentinel) is true. */ @@ -119,26 +140,27 @@ struct posix_acl *get_acl(struct inode *inode, int type) * current value of the ACL will not be ACL_NOT_CACHED and so our own * sentinel will not be set; another task will update the cache. We * could wait for that other task to complete its job, but it's easier - * to just call ->get_acl to fetch the ACL ourself. (This is going to - * be an unlikely race.) + * to just call ->get_inode_acl to fetch the ACL ourself. (This is + * going to be an unlikely race.) */ - if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) - /* fall through */ ; + cmpxchg(p, ACL_NOT_CACHED, sentinel); /* - * Normally, the ACL returned by ->get_acl will be cached. + * Normally, the ACL returned by ->get{_inode}_acl will be cached. * A filesystem can prevent that by calling - * forget_cached_acl(inode, type) in ->get_acl. + * forget_cached_acl(inode, type) in ->get{_inode}_acl. * - * If the filesystem doesn't have a get_acl() function at all, we'll - * just create the negative cache entry. + * If the filesystem doesn't have a get{_inode}_ acl() function at all, + * we'll just create the negative cache entry. */ - if (!inode->i_op->get_acl) { + if (dentry && inode->i_op->get_acl) { + acl = inode->i_op->get_acl(idmap, dentry, type); + } else if (inode->i_op->get_inode_acl) { + acl = inode->i_op->get_inode_acl(inode, type, false); + } else { set_cached_acl(inode, type, NULL); return NULL; } - acl = inode->i_op->get_acl(inode, type); - if (IS_ERR(acl)) { /* * Remove our sentinel so that we don't block future attempts @@ -152,11 +174,16 @@ struct posix_acl *get_acl(struct inode *inode, int type) * Cache the result, but only if our sentinel is still in place. */ posix_acl_dup(acl); - if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) + if (unlikely(!try_cmpxchg(p, &sentinel, acl))) posix_acl_release(acl); return acl; } -EXPORT_SYMBOL(get_acl); + +struct posix_acl *get_inode_acl(struct inode *inode, int type) +{ + return __get_acl(&nop_mnt_idmap, NULL, inode, type); +} +EXPORT_SYMBOL(get_inode_acl); /* * Init a fresh posix_acl @@ -173,11 +200,11 @@ EXPORT_SYMBOL(posix_acl_init); * Allocate a new ACL with the specified number of entries. */ struct posix_acl * -posix_acl_alloc(int count, gfp_t flags) +posix_acl_alloc(unsigned int count, gfp_t flags) { - const size_t size = sizeof(struct posix_acl) + - count * sizeof(struct posix_acl_entry); - struct posix_acl *acl = kmalloc(size, flags); + struct posix_acl *acl; + + acl = kmalloc(struct_size(acl, a_entries, count), flags); if (acl) posix_acl_init(acl, count); return acl; @@ -187,20 +214,20 @@ EXPORT_SYMBOL(posix_acl_alloc); /* * Clone an ACL. */ -static struct posix_acl * +struct posix_acl * posix_acl_clone(const struct posix_acl *acl, gfp_t flags) { struct posix_acl *clone = NULL; if (acl) { - int size = sizeof(struct posix_acl) + acl->a_count * - sizeof(struct posix_acl_entry); - clone = kmemdup(acl, size, flags); + clone = kmemdup(acl, struct_size(acl, a_entries, acl->a_count), + flags); if (clone) refcount_set(&clone->a_refcount, 1); } return clone; } +EXPORT_SYMBOL_GPL(posix_acl_clone); /* * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. @@ -344,33 +371,43 @@ 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 mnt_idmap *idmap, struct inode *inode, + const struct posix_acl *acl, int want) { const struct posix_acl_entry *pa, *pe, *mask_obj; + struct user_namespace *fs_userns = i_user_ns(inode); int found = 0; + vfsuid_t vfsuid; + vfsgid_t vfsgid; - want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK; + want &= MAY_READ | MAY_WRITE | MAY_EXEC; FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { case ACL_USER_OBJ: /* (May have been checked already) */ - if (uid_eq(inode->i_uid, current_fsuid())) + vfsuid = i_uid_into_vfsuid(idmap, inode); + if (vfsuid_eq_kuid(vfsuid, current_fsuid())) goto check_perm; break; case ACL_USER: - if (uid_eq(pa->e_uid, current_fsuid())) + vfsuid = make_vfsuid(idmap, fs_userns, + pa->e_uid); + if (vfsuid_eq_kuid(vfsuid, current_fsuid())) goto mask; break; case ACL_GROUP_OBJ: - if (in_group_p(inode->i_gid)) { + vfsgid = i_gid_into_vfsgid(idmap, inode); + if (vfsgid_in_group_p(vfsgid)) { found = 1; if ((pa->e_perm & want) == want) goto mask; } break; case ACL_GROUP: - if (in_group_p(pa->e_gid)) { + vfsgid = make_vfsgid(idmap, fs_userns, + pa->e_gid); + if (vfsgid_in_group_p(vfsgid)) { found = 1; if ((pa->e_perm & want) == want) goto mask; @@ -550,9 +587,24 @@ __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) } EXPORT_SYMBOL(__posix_acl_chmod); +/** + * posix_acl_chmod - chmod a posix acl + * + * @idmap: idmap of the mount @inode was found from + * @dentry: dentry to check permissions on + * @mode: the new mode of @inode + * + * If the dentry has been found through an idmapped mount the idmap of + * the vfsmount must be passed through @idmap. This function will then + * take care to map the inode according to @idmap before checking + * permissions. On non-idmapped mounts or if permission checking is to be + * performed on the raw inode simply pass @nop_mnt_idmap. + */ int -posix_acl_chmod(struct inode *inode, umode_t mode) + posix_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry, + umode_t mode) { + struct inode *inode = d_inode(dentry); struct posix_acl *acl; int ret = 0; @@ -561,7 +613,7 @@ posix_acl_chmod(struct inode *inode, umode_t mode) if (!inode->i_op->set_acl) return -EOPNOTSUPP; - acl = get_acl(inode, ACL_TYPE_ACCESS); + acl = get_inode_acl(inode, ACL_TYPE_ACCESS); if (IS_ERR_OR_NULL(acl)) { if (acl == ERR_PTR(-EOPNOTSUPP)) return 0; @@ -571,7 +623,7 @@ posix_acl_chmod(struct inode *inode, umode_t mode) ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); if (ret) return ret; - ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS); + ret = inode->i_op->set_acl(idmap, dentry, acl, ACL_TYPE_ACCESS); posix_acl_release(acl); return ret; } @@ -591,7 +643,7 @@ posix_acl_create(struct inode *dir, umode_t *mode, if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) return 0; - p = get_acl(dir, ACL_TYPE_DEFAULT); + p = get_inode_acl(dir, ACL_TYPE_DEFAULT); if (!p || p == ERR_PTR(-EOPNOTSUPP)) { *mode &= ~current_umask(); return 0; @@ -630,17 +682,28 @@ EXPORT_SYMBOL_GPL(posix_acl_create); /** * posix_acl_update_mode - update mode in set_acl + * @idmap: idmap of the mount @inode was found from + * @inode: target inode + * @mode_p: mode (pointer) for update + * @acl: acl pointer * * Update the file mode when setting an ACL: compute the new file permission * bits based on the ACL. In addition, if the ACL is equivalent to the new - * file mode, set *acl to NULL to indicate that no ACL should be set. + * file mode, set *@acl to NULL to indicate that no ACL should be set. * - * As with chmod, clear the setgit bit if the caller is not in the owning group + * As with chmod, clear the setgid bit if the caller is not in the owning group * or capable of CAP_FSETID (see inode_change_ok). * + * If the inode has been found through an idmapped mount the idmap of + * the vfsmount must be passed through @idmap. This function will then + * take care to map the inode according to @idmap before checking + * permissions. On non-idmapped mounts or if permission checking is to be + * performed on the raw inode simply pass @nop_mnt_idmap. + * * Called from set_acl inode operations. */ -int posix_acl_update_mode(struct inode *inode, umode_t *mode_p, +int posix_acl_update_mode(struct mnt_idmap *idmap, + struct inode *inode, umode_t *mode_p, struct posix_acl **acl) { umode_t mode = inode->i_mode; @@ -651,8 +714,8 @@ int posix_acl_update_mode(struct inode *inode, umode_t *mode_p, return error; if (error == 0) *acl = NULL; - if (!in_group_p(inode->i_gid) && - !capable_wrt_inode_uidgid(inode, CAP_FSETID)) + if (!in_group_or_capable(idmap, inode, + i_gid_into_vfsgid(idmap, inode))) mode &= ~S_ISGID; *mode_p = mode; return 0; @@ -662,67 +725,53 @@ EXPORT_SYMBOL(posix_acl_update_mode); /* * Fix up the uids and gids in posix acl extended attributes in place. */ -static void posix_acl_fix_xattr_userns( - struct user_namespace *to, struct user_namespace *from, - void *value, size_t size) +static int posix_acl_fix_xattr_common(const void *value, size_t size) { - struct posix_acl_xattr_header *header = value; - struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; + const struct posix_acl_xattr_header *header = value; int count; - kuid_t uid; - kgid_t gid; - if (!value) - return; + if (!header) + return -EINVAL; if (size < sizeof(struct posix_acl_xattr_header)) - return; + return -EINVAL; if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) - return; + return -EOPNOTSUPP; count = posix_acl_xattr_count(size); if (count < 0) - return; + return -EINVAL; if (count == 0) - return; - - 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)); - break; - case ACL_GROUP: - gid = make_kgid(from, le32_to_cpu(entry->e_id)); - entry->e_id = cpu_to_le32(from_kgid(to, gid)); - break; - default: - break; - } - } -} - -void posix_acl_fix_xattr_from_user(void *value, size_t size) -{ - struct user_namespace *user_ns = current_user_ns(); - if (user_ns == &init_user_ns) - return; - posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); -} + return 0; -void posix_acl_fix_xattr_to_user(void *value, size_t size) -{ - struct user_namespace *user_ns = current_user_ns(); - if (user_ns == &init_user_ns) - return; - posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); + return count; } -/* - * Convert from extended attribute to in-memory representation. +/** + * posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format + * @userns: the filesystem's idmapping + * @value: the uapi representation of POSIX ACLs + * @size: the size of @void + * + * Filesystems that store POSIX ACLs in the unaltered uapi format should use + * posix_acl_from_xattr() when reading them from the backing store and + * converting them into the struct posix_acl VFS format. The helper is + * specifically intended to be called from the acl inode operation. + * + * The posix_acl_from_xattr() function will map the raw {g,u}id values stored + * in ACL_{GROUP,USER} entries into idmapping in @userns. + * + * Note that posix_acl_from_xattr() does not take idmapped mounts into account. + * If it did it calling it from the get acl inode operation would return POSIX + * ACLs mapped according to an idmapped mount which would mean that the value + * couldn't be cached for the filesystem. Idmapped mounts are taken into + * account on the fly during permission checking or right at the VFS - + * userspace boundary before reporting them to the user. + * + * Return: Allocated struct posix_acl on success, NULL for a valid header but + * without actual POSIX ACL entries, or ERR_PTR() encoded error code. */ -struct posix_acl * -posix_acl_from_xattr(struct user_namespace *user_ns, - const void *value, size_t size) +struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns, + const void *value, size_t size) { const struct posix_acl_xattr_header *header = value; const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end; @@ -730,24 +779,17 @@ posix_acl_from_xattr(struct user_namespace *user_ns, struct posix_acl *acl; struct posix_acl_entry *acl_e; - if (!value) - return NULL; - if (size < sizeof(struct posix_acl_xattr_header)) - return ERR_PTR(-EINVAL); - if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) - return ERR_PTR(-EOPNOTSUPP); - - count = posix_acl_xattr_count(size); + count = posix_acl_fix_xattr_common(value, size); if (count < 0) - return ERR_PTR(-EINVAL); + return ERR_PTR(count); 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); @@ -760,16 +802,14 @@ posix_acl_from_xattr(struct user_namespace *user_ns, break; case ACL_USER: - acl_e->e_uid = - make_kuid(user_ns, - le32_to_cpu(entry->e_id)); + acl_e->e_uid = make_kuid(userns, + 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, - le32_to_cpu(entry->e_id)); + acl_e->e_gid = make_kgid(userns, + le32_to_cpu(entry->e_id)); if (!gid_valid(acl_e->e_gid)) goto fail; break; @@ -828,34 +868,74 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, } EXPORT_SYMBOL (posix_acl_to_xattr); -static int -posix_acl_xattr_get(const struct xattr_handler *handler, - struct dentry *unused, struct inode *inode, - const char *name, void *value, size_t size) -{ - struct posix_acl *acl; - int error; +/** + * vfs_posix_acl_to_xattr - convert from kernel to userspace representation + * @idmap: idmap of the mount + * @inode: inode the posix acls are set on + * @acl: the posix acls as represented by the vfs + * @buffer: the buffer into which to convert @acl + * @size: size of @buffer + * + * This converts @acl from the VFS representation in the filesystem idmapping + * to the uapi form reportable to userspace. And mount and caller idmappings + * are handled appropriately. + * + * Return: On success, the size of the stored uapi posix acls, on error a + * negative errno. + */ +static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap, + struct inode *inode, + const struct posix_acl *acl, void *buffer, + size_t size) - if (!IS_POSIXACL(inode)) - return -EOPNOTSUPP; - if (S_ISLNK(inode->i_mode)) - return -EOPNOTSUPP; +{ + struct posix_acl_xattr_header *ext_acl = buffer; + struct posix_acl_xattr_entry *ext_entry; + struct user_namespace *fs_userns, *caller_userns; + ssize_t real_size, n; + vfsuid_t vfsuid; + vfsgid_t vfsgid; - acl = get_acl(inode, handler->flags); - if (IS_ERR(acl)) - return PTR_ERR(acl); - if (acl == NULL) - return -ENODATA; + real_size = posix_acl_xattr_size(acl->a_count); + if (!buffer) + return real_size; + if (real_size > size) + return -ERANGE; - error = posix_acl_to_xattr(&init_user_ns, acl, value, size); - posix_acl_release(acl); + ext_entry = (void *)(ext_acl + 1); + ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); - return error; + fs_userns = i_user_ns(inode); + caller_userns = current_user_ns(); + for (n=0; n < acl->a_count; n++, ext_entry++) { + const struct posix_acl_entry *acl_e = &acl->a_entries[n]; + ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); + ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); + switch(acl_e->e_tag) { + case ACL_USER: + vfsuid = make_vfsuid(idmap, fs_userns, acl_e->e_uid); + ext_entry->e_id = cpu_to_le32(from_kuid( + caller_userns, vfsuid_into_kuid(vfsuid))); + break; + case ACL_GROUP: + vfsgid = make_vfsgid(idmap, fs_userns, acl_e->e_gid); + ext_entry->e_id = cpu_to_le32(from_kgid( + caller_userns, vfsgid_into_kgid(vfsgid))); + break; + default: + ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); + break; + } + } + return real_size; } int -set_posix_acl(struct inode *inode, int type, struct posix_acl *acl) +set_posix_acl(struct mnt_idmap *idmap, struct dentry *dentry, + int type, struct posix_acl *acl) { + struct inode *inode = d_inode(dentry); + if (!IS_POSIXACL(inode)) return -EOPNOTSUPP; if (!inode->i_op->set_acl) @@ -863,7 +943,7 @@ set_posix_acl(struct inode *inode, int type, struct posix_acl *acl) if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) return acl ? -EACCES : 0; - if (!inode_owner_or_capable(inode)) + if (!inode_owner_or_capable(idmap, inode)) return -EPERM; if (acl) { @@ -871,27 +951,33 @@ set_posix_acl(struct inode *inode, int type, struct posix_acl *acl) if (ret) return ret; } - return inode->i_op->set_acl(inode, acl, type); + return inode->i_op->set_acl(idmap, dentry, acl, type); } EXPORT_SYMBOL(set_posix_acl); -static int -posix_acl_xattr_set(const struct xattr_handler *handler, - struct dentry *unused, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) +int posix_acl_listxattr(struct inode *inode, char **buffer, + ssize_t *remaining_size) { - struct posix_acl *acl = NULL; - int ret; + int err; - if (value) { - acl = posix_acl_from_xattr(&init_user_ns, value, size); - if (IS_ERR(acl)) - return PTR_ERR(acl); + if (!IS_POSIXACL(inode)) + return 0; + + if (inode->i_acl) { + err = xattr_list_one(buffer, remaining_size, + XATTR_NAME_POSIX_ACL_ACCESS); + if (err) + return err; } - ret = set_posix_acl(inode, handler->flags, acl); - posix_acl_release(acl); - return ret; + + if (inode->i_default_acl) { + err = xattr_list_one(buffer, remaining_size, + XATTR_NAME_POSIX_ACL_DEFAULT); + if (err) + return err; + } + + return 0; } static bool @@ -900,36 +986,48 @@ posix_acl_xattr_list(struct dentry *dentry) return IS_POSIXACL(d_backing_inode(dentry)); } -const struct xattr_handler posix_acl_access_xattr_handler = { +/* + * nop_posix_acl_access - legacy xattr handler for access POSIX ACLs + * + * This is the legacy POSIX ACL access xattr handler. It is used by some + * filesystems to implement their ->listxattr() inode operation. New code + * should never use them. + */ +const struct xattr_handler nop_posix_acl_access = { .name = XATTR_NAME_POSIX_ACL_ACCESS, - .flags = ACL_TYPE_ACCESS, .list = posix_acl_xattr_list, - .get = posix_acl_xattr_get, - .set = posix_acl_xattr_set, }; -EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); +EXPORT_SYMBOL_GPL(nop_posix_acl_access); -const struct xattr_handler posix_acl_default_xattr_handler = { +/* + * nop_posix_acl_default - legacy xattr handler for default POSIX ACLs + * + * This is the legacy POSIX ACL default xattr handler. It is used by some + * filesystems to implement their ->listxattr() inode operation. New code + * should never use them. + */ +const struct xattr_handler nop_posix_acl_default = { .name = XATTR_NAME_POSIX_ACL_DEFAULT, - .flags = ACL_TYPE_DEFAULT, .list = posix_acl_xattr_list, - .get = posix_acl_xattr_get, - .set = posix_acl_xattr_set, }; -EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); +EXPORT_SYMBOL_GPL(nop_posix_acl_default); -int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type) +int simple_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, + struct posix_acl *acl, int type) { int error; + struct inode *inode = d_inode(dentry); if (type == ACL_TYPE_ACCESS) { - error = posix_acl_update_mode(inode, + error = posix_acl_update_mode(idmap, inode, &inode->i_mode, &acl); if (error) return error; } - inode->i_ctime = current_time(inode); + inode_set_ctime_current(inode); + if (IS_I_VERSION(inode)) + inode_inc_iversion(inode); set_cached_acl(inode, type, acl); return 0; } @@ -952,3 +1050,248 @@ int simple_acl_create(struct inode *dir, struct inode *inode) posix_acl_release(acl); return 0; } + +static int vfs_set_acl_idmapped_mnt(struct mnt_idmap *idmap, + struct user_namespace *fs_userns, + struct posix_acl *acl) +{ + for (int n = 0; n < acl->a_count; n++) { + struct posix_acl_entry *acl_e = &acl->a_entries[n]; + + switch (acl_e->e_tag) { + case ACL_USER: + acl_e->e_uid = from_vfsuid(idmap, fs_userns, + VFSUIDT_INIT(acl_e->e_uid)); + break; + case ACL_GROUP: + acl_e->e_gid = from_vfsgid(idmap, fs_userns, + VFSGIDT_INIT(acl_e->e_gid)); + break; + } + } + + return 0; +} + +/** + * vfs_set_acl - set posix acls + * @idmap: idmap of the mount + * @dentry: the dentry based on which to set the posix acls + * @acl_name: the name of the posix acl + * @kacl: the posix acls in the appropriate VFS format + * + * This function sets @kacl. The caller must all posix_acl_release() on @kacl + * afterwards. + * + * Return: On success 0, on error negative errno. + */ +int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) +{ + int acl_type; + int error; + struct inode *inode = d_inode(dentry); + struct delegated_inode delegated_inode = { }; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return -EINVAL; + + if (kacl) { + /* + * If we're on an idmapped mount translate from mount specific + * vfs{g,u}id_t into global filesystem k{g,u}id_t. + * Afterwards we can cache the POSIX ACLs filesystem wide and - + * if this is a filesystem with a backing store - ultimately + * translate them to backing store values. + */ + error = vfs_set_acl_idmapped_mnt(idmap, i_user_ns(inode), kacl); + if (error) + return error; + } + +retry_deleg: + inode_lock(inode); + + /* + * We only care about restrictions the inode struct itself places upon + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. + */ + error = may_write_xattr(idmap, inode); + if (error) + goto out_inode_unlock; + + error = security_inode_set_acl(idmap, dentry, acl_name, kacl); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (likely(!is_bad_inode(inode))) + error = set_posix_acl(idmap, dentry, acl_type, kacl); + else + error = -EIO; + if (!error) { + fsnotify_xattr(dentry); + security_inode_post_set_acl(dentry, acl_name, kacl); + } + +out_inode_unlock: + inode_unlock(inode); + + if (is_delegated(&delegated_inode)) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL_GPL(vfs_set_acl); + +/** + * vfs_get_acl - get posix acls + * @idmap: idmap of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function retrieves @kacl from the filesystem. The caller must all + * posix_acl_release() on @kacl. + * + * Return: On success POSIX ACLs in VFS format, on error negative errno. + */ +struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap, + struct dentry *dentry, const char *acl_name) +{ + struct inode *inode = d_inode(dentry); + struct posix_acl *acl; + int acl_type, error; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return ERR_PTR(-EINVAL); + + /* + * The VFS has no restrictions on reading POSIX ACLs so calling + * something like xattr_permission() isn't needed. Only LSMs get a say. + */ + error = security_inode_get_acl(idmap, dentry, acl_name); + if (error) + return ERR_PTR(error); + + if (!IS_POSIXACL(inode)) + return ERR_PTR(-EOPNOTSUPP); + if (S_ISLNK(inode->i_mode)) + return ERR_PTR(-EOPNOTSUPP); + + acl = __get_acl(idmap, dentry, inode, acl_type); + if (IS_ERR(acl)) + return acl; + if (!acl) + return ERR_PTR(-ENODATA); + + return acl; +} +EXPORT_SYMBOL_GPL(vfs_get_acl); + +/** + * vfs_remove_acl - remove posix acls + * @idmap: idmap of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function removes posix acls. + * + * Return: On success 0, on error negative errno. + */ +int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name) +{ + int acl_type; + int error; + struct inode *inode = d_inode(dentry); + struct delegated_inode delegated_inode = { }; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return -EINVAL; + +retry_deleg: + inode_lock(inode); + + /* + * We only care about restrictions the inode struct itself places upon + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. + */ + error = may_write_xattr(idmap, inode); + if (error) + goto out_inode_unlock; + + error = security_inode_remove_acl(idmap, dentry, acl_name); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (likely(!is_bad_inode(inode))) + error = set_posix_acl(idmap, dentry, acl_type, NULL); + else + error = -EIO; + if (!error) { + fsnotify_xattr(dentry); + security_inode_post_remove_acl(idmap, dentry, acl_name); + } + +out_inode_unlock: + inode_unlock(inode); + + if (is_delegated(&delegated_inode)) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL_GPL(vfs_remove_acl); + +int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name, const void *kvalue, size_t size) +{ + int error; + struct posix_acl *acl = NULL; + + if (size) { + /* + * Note that posix_acl_from_xattr() uses GFP_NOFS when it + * probably doesn't need to here. + */ + acl = posix_acl_from_xattr(current_user_ns(), kvalue, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + } + + error = vfs_set_acl(idmap, dentry, acl_name, acl); + posix_acl_release(acl); + return error; +} + +ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name, void *kvalue, size_t size) +{ + ssize_t error; + struct posix_acl *acl; + + acl = vfs_get_acl(idmap, dentry, acl_name); + if (IS_ERR(acl)) + return PTR_ERR(acl); + + error = vfs_posix_acl_to_xattr(idmap, d_inode(dentry), + acl, kvalue, size); + posix_acl_release(acl); + return error; +} |