diff options
Diffstat (limited to 'drivers/staging/erofs/xattr.c')
-rw-r--r-- | drivers/staging/erofs/xattr.c | 577 |
1 files changed, 577 insertions, 0 deletions
diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c new file mode 100644 index 000000000000..0e9cfeccdf99 --- /dev/null +++ b/drivers/staging/erofs/xattr.c @@ -0,0 +1,577 @@ +// 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 ofs; +}; + +static inline void xattr_iter_end(struct xattr_iter *it, bool atomic) +{ + /* only init_inode_xattrs use non-atomic once */ + if (unlikely(!atomic)) + kunmap(it->page); + else + kunmap_atomic(it->kaddr); + unlock_page(it->page); + put_page(it->page); +} + +static void init_inode_xattrs(struct inode *inode) +{ + struct xattr_iter it; + unsigned i; + struct erofs_xattr_ibody_header *ih; + struct erofs_sb_info *sbi; + struct erofs_vnode *vi; + bool atomic_map; + + if (likely(inode_has_inited_xattr(inode))) + return; + + vi = EROFS_V(inode); + BUG_ON(!vi->xattr_isize); + + sbi = EROFS_I_SB(inode); + 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); + BUG_ON(IS_ERR(it.page)); + + /* 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 = (unsigned *)kmalloc_array( + vi->xattr_shared_count, sizeof(unsigned), + GFP_KERNEL | __GFP_NOFAIL); + + /* 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(inode->i_sb, + ++it.blkaddr, S_ISDIR(inode->i_mode)); + BUG_ON(IS_ERR(it.page)); + + 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); + + inode_set_inited_xattr(inode); +} + +struct xattr_iter_handlers { + int (*entry)(struct xattr_iter *, struct erofs_xattr_entry *); + int (*name)(struct xattr_iter *, unsigned, char *, unsigned); + int (*alloc_buffer)(struct xattr_iter *, unsigned); + void (*value)(struct xattr_iter *, unsigned, char *, unsigned); +}; + +static void xattr_iter_fixup(struct xattr_iter *it) +{ + if (unlikely(it->ofs >= EROFS_BLKSIZ)) { + xattr_iter_end(it, true); + + it->blkaddr += erofs_blknr(it->ofs); + it->page = erofs_get_meta_page(it->sb, it->blkaddr, false); + BUG_ON(IS_ERR(it->page)); + + it->kaddr = kmap_atomic(it->page); + it->ofs = erofs_blkoff(it->ofs); + } +} + +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 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); + BUG_ON(IS_ERR(it->page)); + it->kaddr = kmap_atomic(it->page); + + return vi->xattr_isize - xattr_header_sz; +} + +static int xattr_foreach(struct xattr_iter *it, + struct xattr_iter_handlers *op, unsigned *tlimit) +{ + struct erofs_xattr_entry entry; + unsigned value_sz, processed, slice; + int err; + + /* 0. fixup blkaddr, ofs, ipage */ + xattr_iter_fixup(it); + + /* + * 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 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); + + xattr_iter_fixup(it); + it->ofs = 0; + } + + slice = min_t(unsigned, 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); + xattr_iter_fixup(it); + it->ofs = 0; + } + + slice = min_t(unsigned, PAGE_SIZE - it->ofs, + value_sz - processed); + op->value(it, processed, it->kaddr + it->ofs, slice); + it->ofs += slice; + processed += slice; + } + +out: + /* we assume that ofs is aligned with 4 bytes */ + it->ofs = EROFS_XATTR_ALIGN(it->ofs); + return err; +} + +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 processed, char *buf, unsigned 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 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 processed, char *buf, unsigned len) +{ + struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); + + memcpy(it->buffer + processed, buf, len); +} + +static 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 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 >= 0) + break; + } + xattr_iter_end(&it->it, true); + + return ret < 0 ? ret : it->buffer_size; +} + +static int shared_getxattr(struct inode *inode, struct getxattr_iter *it) +{ + struct erofs_vnode *const vi = EROFS_V(inode); + struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb); + unsigned 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(inode->i_sb, + blkaddr, false); + BUG_ON(IS_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 >= 0) + break; + } + if (vi->xattr_shared_count) + xattr_iter_end(&it->it, true); + + return ret < 0 ? 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; + + init_inode_xattrs(inode); + + 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_vnode *const vi = EROFS_V(inode); + 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; + } + + if (!vi->xattr_isize) + return -ENOATTR; + + 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 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; + + /* Note that at least one of 'prefix' and 'name' should be non-NULL */ + prefix = h->prefix != NULL ? h->prefix : h->name; + 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 processed, char *buf, unsigned 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 value_sz) +{ + struct listxattr_iter *it = + container_of(_it, struct listxattr_iter, it); + + it->buffer[it->buffer_ofs++] = '\0'; + return 1; +} + +static 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 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 < 0) + break; + } + xattr_iter_end(&it->it, true); + return ret < 0 ? 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 erofs_sb_info *const sbi = EROFS_I_SB(inode); + unsigned 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(inode->i_sb, + blkaddr, false); + BUG_ON(IS_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 < 0) + break; + } + if (vi->xattr_shared_count) + xattr_iter_end(&it->it, true); + + return ret < 0 ? ret : it->buffer_ofs; +} + +ssize_t erofs_listxattr(struct dentry *dentry, + char *buffer, size_t buffer_size) +{ + int ret; + struct listxattr_iter it; + + init_inode_xattrs(d_inode(dentry)); + + 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); +} + |