// SPDX-License-Identifier: GPL-2.0 /* * linux/fs/ext4/acl.c * * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> */ #include <linux/quotaops.h> #include "ext4_jbd2.h" #include "ext4.h" #include "xattr.h" #include "acl.h" /* * Convert from filesystem to in-memory representation. */ static struct posix_acl * ext4_acl_from_disk(const void *value, size_t size) { const char *end = (char *)value + size; int n, count; struct posix_acl *acl; if (!value) return NULL; if (size < sizeof(ext4_acl_header)) return ERR_PTR(-EINVAL); if (((ext4_acl_header *)value)->a_version != cpu_to_le32(EXT4_ACL_VERSION)) return ERR_PTR(-EINVAL); value = (char *)value + sizeof(ext4_acl_header); count = ext4_acl_count(size); if (count < 0) return ERR_PTR(-EINVAL); if (count == 0) return NULL; acl = posix_acl_alloc(count, GFP_NOFS); if (!acl) return ERR_PTR(-ENOMEM); for (n = 0; n < count; n++) { ext4_acl_entry *entry = (ext4_acl_entry *)value; if ((char *)value + sizeof(ext4_acl_entry_short) > end) goto fail; acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); switch (acl->a_entries[n].e_tag) { case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: value = (char *)value + sizeof(ext4_acl_entry_short); break; case ACL_USER: value = (char *)value + sizeof(ext4_acl_entry); if ((char *)value > end) goto fail; acl->a_entries[n].e_uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); break; case ACL_GROUP: value = (char *)value + sizeof(ext4_acl_entry); if ((char *)value > end) goto fail; acl->a_entries[n].e_gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); break; default: goto fail; } } if (value != end) goto fail; return acl; fail: posix_acl_release(acl); return ERR_PTR(-EINVAL); } /* * Convert from in-memory to filesystem representation. */ static void * ext4_acl_to_disk(const struct posix_acl *acl, size_t *size) { ext4_acl_header *ext_acl; char *e; size_t n; *size = ext4_acl_size(acl->a_count); ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count * sizeof(ext4_acl_entry), GFP_NOFS); if (!ext_acl) return ERR_PTR(-ENOMEM); ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION); e = (char *)ext_acl + sizeof(ext4_acl_header); for (n = 0; n < acl->a_count; n++) { const struct posix_acl_entry *acl_e = &acl->a_entries[n]; ext4_acl_entry *entry = (ext4_acl_entry *)e; entry->e_tag = cpu_to_le16(acl_e->e_tag); entry->e_perm = cpu_to_le16(acl_e->e_perm); switch (acl_e->e_tag) { case ACL_USER: entry->e_id = cpu_to_le32( from_kuid(&init_user_ns, acl_e->e_uid)); e += sizeof(ext4_acl_entry); break; case ACL_GROUP: entry->e_id = cpu_to_le32( from_kgid(&init_user_ns, acl_e->e_gid)); e += sizeof(ext4_acl_entry); break; case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: e += sizeof(ext4_acl_entry_short); break; default: goto fail; } } return (char *)ext_acl; fail: kfree(ext_acl); return ERR_PTR(-EINVAL); } /* * Inode operation get_posix_acl(). * * inode->i_mutex: don't care */ struct posix_acl * ext4_get_acl(struct inode *inode, int type) { int name_index; char *value = NULL; struct posix_acl *acl; int retval; switch (type) { case ACL_TYPE_ACCESS: name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; break; case ACL_TYPE_DEFAULT: name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; break; default: BUG(); } retval = ext4_xattr_get(inode, name_index, "", NULL, 0); if (retval > 0) { value = kmalloc(retval, GFP_NOFS); if (!value) return ERR_PTR(-ENOMEM); retval = ext4_xattr_get(inode, name_index, "", value, retval); } if (retval > 0) acl = ext4_acl_from_disk(value, retval); else if (retval == -ENODATA || retval == -ENOSYS) acl = NULL; else acl = ERR_PTR(retval); kfree(value); return acl; } /* * Set the access or default ACL of an inode. * * inode->i_mutex: down unless called from ext4_new_inode */ static int __ext4_set_acl(handle_t *handle, struct inode *inode, int type, struct posix_acl *acl, int xattr_flags) { int name_index; void *value = NULL; size_t size = 0; int error; switch (type) { case ACL_TYPE_ACCESS: name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; break; case ACL_TYPE_DEFAULT: name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; if (!S_ISDIR(inode->i_mode)) return acl ? -EACCES : 0; break; default: return -EINVAL; } if (acl) { value = ext4_acl_to_disk(acl, &size); if (IS_ERR(value)) return (int)PTR_ERR(value); } error = ext4_xattr_set_handle(handle, inode, name_index, "", value, size, xattr_flags); kfree(value); if (!error) { set_cached_acl(inode, type, acl); } return error; } int ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type) { handle_t *handle; int error, credits, retries = 0; size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0; umode_t mode = inode->i_mode; int update_mode = 0; error = dquot_initialize(inode); if (error) return error; retry: error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */, &credits); if (error) return error; handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); if (IS_ERR(handle)) return PTR_ERR(handle); if ((type == ACL_TYPE_ACCESS) && acl) { error = posix_acl_update_mode(inode, &mode, &acl); if (error) goto out_stop; update_mode = 1; } error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */); if (!error && update_mode) { inode->i_mode = mode; inode->i_ctime = current_time(inode); ext4_mark_inode_dirty(handle, inode); } out_stop: ext4_journal_stop(handle); if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; return error; } /* * Initialize the ACLs of a new inode. Called from ext4_new_inode. * * dir->i_mutex: down * inode->i_mutex: up (access to inode is still exclusive) */ int ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) { struct posix_acl *default_acl, *acl; int error; error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); if (error) return error; if (default_acl) { error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT, default_acl, XATTR_CREATE); posix_acl_release(default_acl); } else { inode->i_default_acl = NULL; } if (acl) { if (!error) error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, acl, XATTR_CREATE); posix_acl_release(acl); } else { inode->i_acl = NULL; } return error; }