diff options
Diffstat (limited to 'fs/erofs/xattr.c')
| -rw-r--r-- | fs/erofs/xattr.c | 704 |
1 files changed, 704 insertions, 0 deletions
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c new file mode 100644 index 000000000000..a13a78725c57 --- /dev/null +++ b/fs/erofs/xattr.c @@ -0,0 +1,704 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2017-2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25@huawei.com> + */ +#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 (!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) + return; + + xattr_iter_end(it, true); +} + +static int init_inode_xattrs(struct inode *inode) +{ + struct erofs_inode *const vi = EROFS_I(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_I_EA_INITED_BIT, &vi->flags)) + return 0; + + if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE)) + return -ERESTARTSYS; + + /* someone has initialized xattrs for us? */ + if (test_bit(EROFS_I_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)) { + erofs_err(inode->i_sb, + "xattr_isize %d of nid %llu is not supported yet", + vi->xattr_isize, vi->nid); + ret = -EOPNOTSUPP; + goto out_unlock; + } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { + if (vi->xattr_isize) { + erofs_err(inode->i_sb, + "bogus xattr ibody @ nid %llu", vi->nid); + DBG_BUGON(1); + ret = -EFSCORRUPTED; + 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_meta_page(sb, 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) { + 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 (it.ofs >= EROFS_BLKSIZ) { + /* cannot be unaligned */ + DBG_BUGON(it.ofs != EROFS_BLKSIZ); + xattr_iter_end(&it, atomic_map); + + it.page = erofs_get_meta_page(sb, ++it.blkaddr); + 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_I_EA_INITED_BIT, &vi->flags); + +out_unlock: + clear_and_wake_up_bit(EROFS_I_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); + 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_inode *const vi = EROFS_I(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 (xattr_header_sz >= vi->xattr_isize) { + DBG_BUGON(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_meta_page(inode->i_sb, 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) { + unsigned int entry_sz = erofs_xattr_entry_size(&entry); + + /* xattr on-disk corruption: xattr entry beyond xattr_isize */ + if (*tlimit < entry_sz) { + DBG_BUGON(1); + return -EFSCORRUPTED; + } + *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) { + DBG_BUGON(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) { + err = op->alloc_buffer(it, value_sz); + if (err) { + it->ofs += value_sz; + goto out; + } + } + + while (processed < value_sz) { + if (it->ofs >= EROFS_BLKSIZ) { + DBG_BUGON(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 ? 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_inode *const vi = EROFS_I(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); + 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 (!name) + 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 || (h->list && !h->list(it->dentry))) + return 1; + + prefix = xattr_prefix(h); + prefix_len = strlen(prefix); + + if (!it->buffer) { + 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_inode *const vi = EROFS_I(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); + 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 + |