| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/drivers/staging/erofs/xattr.c |
| * |
| * Copyright (C) 2017-2018 HUAWEI, Inc. |
| * http://www.huawei.com/ |
| * Created by Gao Xiang <gaoxiang25@huawei.com> |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file COPYING in the main directory of the Linux |
| * distribution for more details. |
| */ |
| #include <linux/security.h> |
| #include "xattr.h" |
| |
| struct xattr_iter { |
| struct super_block *sb; |
| struct page *page; |
| void *kaddr; |
| |
| erofs_blk_t blkaddr; |
| unsigned int ofs; |
| }; |
| |
| static inline void xattr_iter_end(struct xattr_iter *it, bool atomic) |
| { |
| /* the only user of kunmap() is 'init_inode_xattrs' */ |
| if (unlikely(!atomic)) |
| kunmap(it->page); |
| else |
| kunmap_atomic(it->kaddr); |
| |
| unlock_page(it->page); |
| put_page(it->page); |
| } |
| |
| static inline void xattr_iter_end_final(struct xattr_iter *it) |
| { |
| if (it->page == NULL) |
| return; |
| |
| xattr_iter_end(it, true); |
| } |
| |
| static int init_inode_xattrs(struct inode *inode) |
| { |
| struct erofs_vnode *const vi = EROFS_V(inode); |
| struct xattr_iter it; |
| unsigned int i; |
| struct erofs_xattr_ibody_header *ih; |
| struct super_block *sb; |
| struct erofs_sb_info *sbi; |
| bool atomic_map; |
| int ret = 0; |
| |
| /* the most case is that xattrs of this inode are initialized. */ |
| if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags)) |
| return 0; |
| |
| if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_XATTR_BIT, TASK_KILLABLE)) |
| return -ERESTARTSYS; |
| |
| /* someone has initialized xattrs for us? */ |
| if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags)) |
| goto out_unlock; |
| |
| /* |
| * bypass all xattr operations if ->xattr_isize is not greater than |
| * sizeof(struct erofs_xattr_ibody_header), in detail: |
| * 1) it is not enough to contain erofs_xattr_ibody_header then |
| * ->xattr_isize should be 0 (it means no xattr); |
| * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk |
| * undefined right now (maybe use later with some new sb feature). |
| */ |
| if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) { |
| errln("xattr_isize %d of nid %llu is not supported yet", |
| vi->xattr_isize, vi->nid); |
| ret = -ENOTSUPP; |
| goto out_unlock; |
| } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { |
| if (unlikely(vi->xattr_isize)) { |
| DBG_BUGON(1); |
| ret = -EIO; |
| goto out_unlock; /* xattr ondisk layout error */ |
| } |
| ret = -ENOATTR; |
| goto out_unlock; |
| } |
| |
| sb = inode->i_sb; |
| sbi = EROFS_SB(sb); |
| it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize); |
| it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize); |
| |
| it.page = erofs_get_inline_page(inode, it.blkaddr); |
| if (IS_ERR(it.page)) { |
| ret = PTR_ERR(it.page); |
| goto out_unlock; |
| } |
| |
| /* read in shared xattr array (non-atomic, see kmalloc below) */ |
| it.kaddr = kmap(it.page); |
| atomic_map = false; |
| |
| ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs); |
| |
| vi->xattr_shared_count = ih->h_shared_count; |
| vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, |
| sizeof(uint), GFP_KERNEL); |
| if (vi->xattr_shared_xattrs == NULL) { |
| xattr_iter_end(&it, atomic_map); |
| ret = -ENOMEM; |
| goto out_unlock; |
| } |
| |
| /* let's skip ibody header */ |
| it.ofs += sizeof(struct erofs_xattr_ibody_header); |
| |
| for (i = 0; i < vi->xattr_shared_count; ++i) { |
| if (unlikely(it.ofs >= EROFS_BLKSIZ)) { |
| /* cannot be unaligned */ |
| BUG_ON(it.ofs != EROFS_BLKSIZ); |
| xattr_iter_end(&it, atomic_map); |
| |
| it.page = erofs_get_meta_page(sb, |
| ++it.blkaddr, S_ISDIR(inode->i_mode)); |
| if (IS_ERR(it.page)) { |
| kfree(vi->xattr_shared_xattrs); |
| vi->xattr_shared_xattrs = NULL; |
| ret = PTR_ERR(it.page); |
| goto out_unlock; |
| } |
| |
| it.kaddr = kmap_atomic(it.page); |
| atomic_map = true; |
| it.ofs = 0; |
| } |
| vi->xattr_shared_xattrs[i] = |
| le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs)); |
| it.ofs += sizeof(__le32); |
| } |
| xattr_iter_end(&it, atomic_map); |
| |
| set_bit(EROFS_V_EA_INITED_BIT, &vi->flags); |
| |
| out_unlock: |
| clear_and_wake_up_bit(EROFS_V_BL_XATTR_BIT, &vi->flags); |
| return ret; |
| } |
| |
| /* |
| * the general idea for these return values is |
| * if 0 is returned, go on processing the current xattr; |
| * 1 (> 0) is returned, skip this round to process the next xattr; |
| * -err (< 0) is returned, an error (maybe ENOXATTR) occurred |
| * and need to be handled |
| */ |
| struct xattr_iter_handlers { |
| int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry); |
| int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf, |
| unsigned int len); |
| int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz); |
| void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf, |
| unsigned int len); |
| }; |
| |
| static inline int xattr_iter_fixup(struct xattr_iter *it) |
| { |
| if (it->ofs < EROFS_BLKSIZ) |
| return 0; |
| |
| xattr_iter_end(it, true); |
| |
| it->blkaddr += erofs_blknr(it->ofs); |
| |
| it->page = erofs_get_meta_page(it->sb, it->blkaddr, false); |
| if (IS_ERR(it->page)) { |
| int err = PTR_ERR(it->page); |
| |
| it->page = NULL; |
| return err; |
| } |
| |
| it->kaddr = kmap_atomic(it->page); |
| it->ofs = erofs_blkoff(it->ofs); |
| return 0; |
| } |
| |
| static int inline_xattr_iter_begin(struct xattr_iter *it, |
| struct inode *inode) |
| { |
| struct erofs_vnode *const vi = EROFS_V(inode); |
| struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb); |
| unsigned int xattr_header_sz, inline_xattr_ofs; |
| |
| xattr_header_sz = inlinexattr_header_size(inode); |
| if (unlikely(xattr_header_sz >= vi->xattr_isize)) { |
| BUG_ON(xattr_header_sz > vi->xattr_isize); |
| return -ENOATTR; |
| } |
| |
| inline_xattr_ofs = vi->inode_isize + xattr_header_sz; |
| |
| it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs); |
| it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs); |
| |
| it->page = erofs_get_inline_page(inode, it->blkaddr); |
| if (IS_ERR(it->page)) |
| return PTR_ERR(it->page); |
| |
| it->kaddr = kmap_atomic(it->page); |
| return vi->xattr_isize - xattr_header_sz; |
| } |
| |
| /* |
| * Regardless of success or failure, `xattr_foreach' will end up with |
| * `ofs' pointing to the next xattr item rather than an arbitrary position. |
| */ |
| static int xattr_foreach(struct xattr_iter *it, |
| const struct xattr_iter_handlers *op, unsigned int *tlimit) |
| { |
| struct erofs_xattr_entry entry; |
| unsigned int value_sz, processed, slice; |
| int err; |
| |
| /* 0. fixup blkaddr, ofs, ipage */ |
| err = xattr_iter_fixup(it); |
| if (err) |
| return err; |
| |
| /* |
| * 1. read xattr entry to the memory, |
| * since we do EROFS_XATTR_ALIGN |
| * therefore entry should be in the page |
| */ |
| entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs); |
| if (tlimit != NULL) { |
| unsigned int entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry); |
| |
| BUG_ON(*tlimit < entry_sz); |
| *tlimit -= entry_sz; |
| } |
| |
| it->ofs += sizeof(struct erofs_xattr_entry); |
| value_sz = le16_to_cpu(entry.e_value_size); |
| |
| /* handle entry */ |
| err = op->entry(it, &entry); |
| if (err) { |
| it->ofs += entry.e_name_len + value_sz; |
| goto out; |
| } |
| |
| /* 2. handle xattr name (ofs will finally be at the end of name) */ |
| processed = 0; |
| |
| while (processed < entry.e_name_len) { |
| if (it->ofs >= EROFS_BLKSIZ) { |
| BUG_ON(it->ofs > EROFS_BLKSIZ); |
| |
| err = xattr_iter_fixup(it); |
| if (err) |
| goto out; |
| it->ofs = 0; |
| } |
| |
| slice = min_t(unsigned int, PAGE_SIZE - it->ofs, |
| entry.e_name_len - processed); |
| |
| /* handle name */ |
| err = op->name(it, processed, it->kaddr + it->ofs, slice); |
| if (err) { |
| it->ofs += entry.e_name_len - processed + value_sz; |
| goto out; |
| } |
| |
| it->ofs += slice; |
| processed += slice; |
| } |
| |
| /* 3. handle xattr value */ |
| processed = 0; |
| |
| if (op->alloc_buffer != NULL) { |
| err = op->alloc_buffer(it, value_sz); |
| if (err) { |
| it->ofs += value_sz; |
| goto out; |
| } |
| } |
| |
| while (processed < value_sz) { |
| if (it->ofs >= EROFS_BLKSIZ) { |
| BUG_ON(it->ofs > EROFS_BLKSIZ); |
| |
| err = xattr_iter_fixup(it); |
| if (err) |
| goto out; |
| it->ofs = 0; |
| } |
| |
| slice = min_t(unsigned int, PAGE_SIZE - it->ofs, |
| value_sz - processed); |
| op->value(it, processed, it->kaddr + it->ofs, slice); |
| it->ofs += slice; |
| processed += slice; |
| } |
| |
| out: |
| /* xattrs should be 4-byte aligned (on-disk constraint) */ |
| it->ofs = EROFS_XATTR_ALIGN(it->ofs); |
| return err < 0 ? err : 0; |
| } |
| |
| struct getxattr_iter { |
| struct xattr_iter it; |
| |
| char *buffer; |
| int buffer_size, index; |
| struct qstr name; |
| }; |
| |
| static int xattr_entrymatch(struct xattr_iter *_it, |
| struct erofs_xattr_entry *entry) |
| { |
| struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); |
| |
| return (it->index != entry->e_name_index || |
| it->name.len != entry->e_name_len) ? -ENOATTR : 0; |
| } |
| |
| static int xattr_namematch(struct xattr_iter *_it, |
| unsigned int processed, char *buf, unsigned int len) |
| { |
| struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); |
| |
| return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0; |
| } |
| |
| static int xattr_checkbuffer(struct xattr_iter *_it, |
| unsigned int value_sz) |
| { |
| struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); |
| int err = it->buffer_size < value_sz ? -ERANGE : 0; |
| |
| it->buffer_size = value_sz; |
| return it->buffer == NULL ? 1 : err; |
| } |
| |
| static void xattr_copyvalue(struct xattr_iter *_it, |
| unsigned int processed, char *buf, unsigned int len) |
| { |
| struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); |
| |
| memcpy(it->buffer + processed, buf, len); |
| } |
| |
| static const struct xattr_iter_handlers find_xattr_handlers = { |
| .entry = xattr_entrymatch, |
| .name = xattr_namematch, |
| .alloc_buffer = xattr_checkbuffer, |
| .value = xattr_copyvalue |
| }; |
| |
| static int inline_getxattr(struct inode *inode, struct getxattr_iter *it) |
| { |
| int ret; |
| unsigned int remaining; |
| |
| ret = inline_xattr_iter_begin(&it->it, inode); |
| if (ret < 0) |
| return ret; |
| |
| remaining = ret; |
| while (remaining) { |
| ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining); |
| if (ret != -ENOATTR) |
| break; |
| } |
| xattr_iter_end_final(&it->it); |
| |
| return ret ? ret : it->buffer_size; |
| } |
| |
| static int shared_getxattr(struct inode *inode, struct getxattr_iter *it) |
| { |
| struct erofs_vnode *const vi = EROFS_V(inode); |
| struct super_block *const sb = inode->i_sb; |
| struct erofs_sb_info *const sbi = EROFS_SB(sb); |
| unsigned int i; |
| int ret = -ENOATTR; |
| |
| for (i = 0; i < vi->xattr_shared_count; ++i) { |
| erofs_blk_t blkaddr = |
| xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]); |
| |
| it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]); |
| |
| if (!i || blkaddr != it->it.blkaddr) { |
| if (i) |
| xattr_iter_end(&it->it, true); |
| |
| it->it.page = erofs_get_meta_page(sb, blkaddr, false); |
| if (IS_ERR(it->it.page)) |
| return PTR_ERR(it->it.page); |
| |
| it->it.kaddr = kmap_atomic(it->it.page); |
| it->it.blkaddr = blkaddr; |
| } |
| |
| ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL); |
| if (ret != -ENOATTR) |
| break; |
| } |
| if (vi->xattr_shared_count) |
| xattr_iter_end_final(&it->it); |
| |
| return ret ? ret : it->buffer_size; |
| } |
| |
| static bool erofs_xattr_user_list(struct dentry *dentry) |
| { |
| return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER); |
| } |
| |
| static bool erofs_xattr_trusted_list(struct dentry *dentry) |
| { |
| return capable(CAP_SYS_ADMIN); |
| } |
| |
| int erofs_getxattr(struct inode *inode, int index, |
| const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| int ret; |
| struct getxattr_iter it; |
| |
| if (unlikely(name == NULL)) |
| return -EINVAL; |
| |
| ret = init_inode_xattrs(inode); |
| if (ret) |
| return ret; |
| |
| it.index = index; |
| |
| it.name.len = strlen(name); |
| if (it.name.len > EROFS_NAME_LEN) |
| return -ERANGE; |
| it.name.name = name; |
| |
| it.buffer = buffer; |
| it.buffer_size = buffer_size; |
| |
| it.it.sb = inode->i_sb; |
| ret = inline_getxattr(inode, &it); |
| if (ret == -ENOATTR) |
| ret = shared_getxattr(inode, &it); |
| return ret; |
| } |
| |
| static int erofs_xattr_generic_get(const struct xattr_handler *handler, |
| struct dentry *unused, struct inode *inode, |
| const char *name, void *buffer, size_t size) |
| { |
| struct erofs_sb_info *const sbi = EROFS_I_SB(inode); |
| |
| switch (handler->flags) { |
| case EROFS_XATTR_INDEX_USER: |
| if (!test_opt(sbi, XATTR_USER)) |
| return -EOPNOTSUPP; |
| break; |
| case EROFS_XATTR_INDEX_TRUSTED: |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| break; |
| case EROFS_XATTR_INDEX_SECURITY: |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| return erofs_getxattr(inode, handler->flags, name, buffer, size); |
| } |
| |
| const struct xattr_handler erofs_xattr_user_handler = { |
| .prefix = XATTR_USER_PREFIX, |
| .flags = EROFS_XATTR_INDEX_USER, |
| .list = erofs_xattr_user_list, |
| .get = erofs_xattr_generic_get, |
| }; |
| |
| const struct xattr_handler erofs_xattr_trusted_handler = { |
| .prefix = XATTR_TRUSTED_PREFIX, |
| .flags = EROFS_XATTR_INDEX_TRUSTED, |
| .list = erofs_xattr_trusted_list, |
| .get = erofs_xattr_generic_get, |
| }; |
| |
| #ifdef CONFIG_EROFS_FS_SECURITY |
| const struct xattr_handler __maybe_unused erofs_xattr_security_handler = { |
| .prefix = XATTR_SECURITY_PREFIX, |
| .flags = EROFS_XATTR_INDEX_SECURITY, |
| .get = erofs_xattr_generic_get, |
| }; |
| #endif |
| |
| const struct xattr_handler *erofs_xattr_handlers[] = { |
| &erofs_xattr_user_handler, |
| #ifdef CONFIG_EROFS_FS_POSIX_ACL |
| &posix_acl_access_xattr_handler, |
| &posix_acl_default_xattr_handler, |
| #endif |
| &erofs_xattr_trusted_handler, |
| #ifdef CONFIG_EROFS_FS_SECURITY |
| &erofs_xattr_security_handler, |
| #endif |
| NULL, |
| }; |
| |
| struct listxattr_iter { |
| struct xattr_iter it; |
| |
| struct dentry *dentry; |
| char *buffer; |
| int buffer_size, buffer_ofs; |
| }; |
| |
| static int xattr_entrylist(struct xattr_iter *_it, |
| struct erofs_xattr_entry *entry) |
| { |
| struct listxattr_iter *it = |
| container_of(_it, struct listxattr_iter, it); |
| unsigned int prefix_len; |
| const char *prefix; |
| |
| const struct xattr_handler *h = |
| erofs_xattr_handler(entry->e_name_index); |
| |
| if (h == NULL || (h->list != NULL && !h->list(it->dentry))) |
| return 1; |
| |
| prefix = xattr_prefix(h); |
| prefix_len = strlen(prefix); |
| |
| if (it->buffer == NULL) { |
| it->buffer_ofs += prefix_len + entry->e_name_len + 1; |
| return 1; |
| } |
| |
| if (it->buffer_ofs + prefix_len |
| + entry->e_name_len + 1 > it->buffer_size) |
| return -ERANGE; |
| |
| memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len); |
| it->buffer_ofs += prefix_len; |
| return 0; |
| } |
| |
| static int xattr_namelist(struct xattr_iter *_it, |
| unsigned int processed, char *buf, unsigned int len) |
| { |
| struct listxattr_iter *it = |
| container_of(_it, struct listxattr_iter, it); |
| |
| memcpy(it->buffer + it->buffer_ofs, buf, len); |
| it->buffer_ofs += len; |
| return 0; |
| } |
| |
| static int xattr_skipvalue(struct xattr_iter *_it, |
| unsigned int value_sz) |
| { |
| struct listxattr_iter *it = |
| container_of(_it, struct listxattr_iter, it); |
| |
| it->buffer[it->buffer_ofs++] = '\0'; |
| return 1; |
| } |
| |
| static const struct xattr_iter_handlers list_xattr_handlers = { |
| .entry = xattr_entrylist, |
| .name = xattr_namelist, |
| .alloc_buffer = xattr_skipvalue, |
| .value = NULL |
| }; |
| |
| static int inline_listxattr(struct listxattr_iter *it) |
| { |
| int ret; |
| unsigned int remaining; |
| |
| ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry)); |
| if (ret < 0) |
| return ret; |
| |
| remaining = ret; |
| while (remaining) { |
| ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining); |
| if (ret) |
| break; |
| } |
| xattr_iter_end_final(&it->it); |
| return ret ? ret : it->buffer_ofs; |
| } |
| |
| static int shared_listxattr(struct listxattr_iter *it) |
| { |
| struct inode *const inode = d_inode(it->dentry); |
| struct erofs_vnode *const vi = EROFS_V(inode); |
| struct super_block *const sb = inode->i_sb; |
| struct erofs_sb_info *const sbi = EROFS_SB(sb); |
| unsigned int i; |
| int ret = 0; |
| |
| for (i = 0; i < vi->xattr_shared_count; ++i) { |
| erofs_blk_t blkaddr = |
| xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]); |
| |
| it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]); |
| if (!i || blkaddr != it->it.blkaddr) { |
| if (i) |
| xattr_iter_end(&it->it, true); |
| |
| it->it.page = erofs_get_meta_page(sb, blkaddr, false); |
| if (IS_ERR(it->it.page)) |
| return PTR_ERR(it->it.page); |
| |
| it->it.kaddr = kmap_atomic(it->it.page); |
| it->it.blkaddr = blkaddr; |
| } |
| |
| ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL); |
| if (ret) |
| break; |
| } |
| if (vi->xattr_shared_count) |
| xattr_iter_end_final(&it->it); |
| |
| return ret ? ret : it->buffer_ofs; |
| } |
| |
| ssize_t erofs_listxattr(struct dentry *dentry, |
| char *buffer, size_t buffer_size) |
| { |
| int ret; |
| struct listxattr_iter it; |
| |
| ret = init_inode_xattrs(d_inode(dentry)); |
| if (ret) |
| return ret; |
| |
| it.dentry = dentry; |
| it.buffer = buffer; |
| it.buffer_size = buffer_size; |
| it.buffer_ofs = 0; |
| |
| it.it.sb = dentry->d_sb; |
| |
| ret = inline_listxattr(&it); |
| if (ret < 0 && ret != -ENOATTR) |
| return ret; |
| return shared_listxattr(&it); |
| } |
| |
| #ifdef CONFIG_EROFS_FS_POSIX_ACL |
| struct posix_acl *erofs_get_acl(struct inode *inode, int type) |
| { |
| struct posix_acl *acl; |
| int prefix, rc; |
| char *value = NULL; |
| |
| switch (type) { |
| case ACL_TYPE_ACCESS: |
| prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS; |
| break; |
| case ACL_TYPE_DEFAULT: |
| prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT; |
| break; |
| default: |
| return ERR_PTR(-EINVAL); |
| } |
| |
| rc = erofs_getxattr(inode, prefix, "", NULL, 0); |
| if (rc > 0) { |
| value = kmalloc(rc, GFP_KERNEL); |
| if (!value) |
| return ERR_PTR(-ENOMEM); |
| rc = erofs_getxattr(inode, prefix, "", value, rc); |
| } |
| |
| if (rc == -ENOATTR) |
| acl = NULL; |
| else if (rc < 0) |
| acl = ERR_PTR(rc); |
| else |
| acl = posix_acl_from_xattr(&init_user_ns, value, rc); |
| kfree(value); |
| return acl; |
| } |
| #endif |
| |