From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/ext4/dir.c | 677 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 677 insertions(+) create mode 100644 fs/ext4/dir.c (limited to 'fs/ext4/dir.c') diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c new file mode 100644 index 000000000..3985f8c33 --- /dev/null +++ b/fs/ext4/dir.c @@ -0,0 +1,677 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ext4/dir.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/dir.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext4 directory handling functions + * + * Big-endian to little-endian byte-swapping/bitmaps by + * David S. Miller (davem@caip.rutgers.edu), 1995 + * + * Hash Tree Directory indexing (c) 2001 Daniel Phillips + * + */ + +#include +#include +#include +#include +#include +#include "ext4.h" +#include "xattr.h" + +static int ext4_dx_readdir(struct file *, struct dir_context *); + +/** + * is_dx_dir() - check if a directory is using htree indexing + * @inode: directory inode + * + * Check if the given dir-inode refers to an htree-indexed directory + * (or a directory which could potentially get converted to use htree + * indexing). + * + * Return 1 if it is a dx dir, 0 if not + */ +static int is_dx_dir(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + + if (ext4_has_feature_dir_index(inode->i_sb) && + ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) || + ((inode->i_size >> sb->s_blocksize_bits) == 1) || + ext4_has_inline_data(inode))) + return 1; + + return 0; +} + +static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de) +{ + /* Check if . or .. , or skip if namelen is 0 */ + if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') && + (de->name[1] == '.' || de->name[1] == '\0')) + return true; + /* Check if this is a csum entry */ + if (de->file_type == EXT4_FT_DIR_CSUM) + return true; + return false; +} + +/* + * Return 0 if the directory entry is OK, and 1 if there is a problem + * + * Note: this is the opposite of what ext2 and ext3 historically returned... + * + * bh passed here can be an inode block or a dir data block, depending + * on the inode inline data flag. + */ +int __ext4_check_dir_entry(const char *function, unsigned int line, + struct inode *dir, struct file *filp, + struct ext4_dir_entry_2 *de, + struct buffer_head *bh, char *buf, int size, + unsigned int offset) +{ + const char *error_msg = NULL; + const int rlen = ext4_rec_len_from_disk(de->rec_len, + dir->i_sb->s_blocksize); + const int next_offset = ((char *) de - buf) + rlen; + bool fake = is_fake_dir_entry(de); + bool has_csum = ext4_has_metadata_csum(dir->i_sb); + + if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir))) + error_msg = "rec_len is smaller than minimal"; + else if (unlikely(rlen % 4 != 0)) + error_msg = "rec_len % 4 != 0"; + else if (unlikely(rlen < ext4_dir_rec_len(de->name_len, + fake ? NULL : dir))) + error_msg = "rec_len is too small for name_len"; + else if (unlikely(next_offset > size)) + error_msg = "directory entry overrun"; + else if (unlikely(next_offset > size - ext4_dir_rec_len(1, + has_csum ? NULL : dir) && + next_offset != size)) + error_msg = "directory entry too close to block end"; + else if (unlikely(le32_to_cpu(de->inode) > + le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))) + error_msg = "inode out of bounds"; + else + return 0; + + if (filp) + ext4_error_file(filp, function, line, bh->b_blocknr, + "bad entry in directory: %s - offset=%u, " + "inode=%u, rec_len=%d, size=%d fake=%d", + error_msg, offset, le32_to_cpu(de->inode), + rlen, size, fake); + else + ext4_error_inode(dir, function, line, bh->b_blocknr, + "bad entry in directory: %s - offset=%u, " + "inode=%u, rec_len=%d, size=%d fake=%d", + error_msg, offset, le32_to_cpu(de->inode), + rlen, size, fake); + + return 1; +} + +static int ext4_readdir(struct file *file, struct dir_context *ctx) +{ + unsigned int offset; + int i; + struct ext4_dir_entry_2 *de; + int err; + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + struct buffer_head *bh = NULL; + struct fscrypt_str fstr = FSTR_INIT(NULL, 0); + + err = fscrypt_prepare_readdir(inode); + if (err) + return err; + + if (is_dx_dir(inode)) { + err = ext4_dx_readdir(file, ctx); + if (err != ERR_BAD_DX_DIR) + return err; + + /* Can we just clear INDEX flag to ignore htree information? */ + if (!ext4_has_metadata_csum(sb)) { + /* + * We don't set the inode dirty flag since it's not + * critical that it gets flushed back to the disk. + */ + ext4_clear_inode_flag(inode, EXT4_INODE_INDEX); + } + } + + if (ext4_has_inline_data(inode)) { + int has_inline_data = 1; + err = ext4_read_inline_dir(file, ctx, + &has_inline_data); + if (has_inline_data) + return err; + } + + if (IS_ENCRYPTED(inode)) { + err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr); + if (err < 0) + return err; + } + + while (ctx->pos < inode->i_size) { + struct ext4_map_blocks map; + + if (fatal_signal_pending(current)) { + err = -ERESTARTSYS; + goto errout; + } + cond_resched(); + offset = ctx->pos & (sb->s_blocksize - 1); + map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb); + map.m_len = 1; + err = ext4_map_blocks(NULL, inode, &map, 0); + if (err == 0) { + /* m_len should never be zero but let's avoid + * an infinite loop if it somehow is */ + if (map.m_len == 0) + map.m_len = 1; + ctx->pos += map.m_len * sb->s_blocksize; + continue; + } + if (err > 0) { + pgoff_t index = map.m_pblk >> + (PAGE_SHIFT - inode->i_blkbits); + if (!ra_has_index(&file->f_ra, index)) + page_cache_sync_readahead( + sb->s_bdev->bd_inode->i_mapping, + &file->f_ra, file, + index, 1); + file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT; + bh = ext4_bread(NULL, inode, map.m_lblk, 0); + if (IS_ERR(bh)) { + err = PTR_ERR(bh); + bh = NULL; + goto errout; + } + } + + if (!bh) { + /* corrupt size? Maybe no more blocks to read */ + if (ctx->pos > inode->i_blocks << 9) + break; + ctx->pos += sb->s_blocksize - offset; + continue; + } + + /* Check the checksum */ + if (!buffer_verified(bh) && + !ext4_dirblock_csum_verify(inode, bh)) { + EXT4_ERROR_FILE(file, 0, "directory fails checksum " + "at offset %llu", + (unsigned long long)ctx->pos); + ctx->pos += sb->s_blocksize - offset; + brelse(bh); + bh = NULL; + continue; + } + set_buffer_verified(bh); + + /* If the dir block has changed since the last call to + * readdir(2), then we might be pointing to an invalid + * dirent right now. Scan from the start of the block + * to make sure. */ + if (!inode_eq_iversion(inode, file->f_version)) { + for (i = 0; i < sb->s_blocksize && i < offset; ) { + de = (struct ext4_dir_entry_2 *) + (bh->b_data + i); + /* It's too expensive to do a full + * dirent test each time round this + * loop, but we do have to test at + * least that it is non-zero. A + * failure will be detected in the + * dirent test below. */ + if (ext4_rec_len_from_disk(de->rec_len, + sb->s_blocksize) < ext4_dir_rec_len(1, + inode)) + break; + i += ext4_rec_len_from_disk(de->rec_len, + sb->s_blocksize); + } + offset = i; + ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) + | offset; + file->f_version = inode_query_iversion(inode); + } + + while (ctx->pos < inode->i_size + && offset < sb->s_blocksize) { + de = (struct ext4_dir_entry_2 *) (bh->b_data + offset); + if (ext4_check_dir_entry(inode, file, de, bh, + bh->b_data, bh->b_size, + offset)) { + /* + * On error, skip to the next block + */ + ctx->pos = (ctx->pos | + (sb->s_blocksize - 1)) + 1; + break; + } + offset += ext4_rec_len_from_disk(de->rec_len, + sb->s_blocksize); + if (le32_to_cpu(de->inode)) { + if (!IS_ENCRYPTED(inode)) { + if (!dir_emit(ctx, de->name, + de->name_len, + le32_to_cpu(de->inode), + get_dtype(sb, de->file_type))) + goto done; + } else { + int save_len = fstr.len; + struct fscrypt_str de_name = + FSTR_INIT(de->name, + de->name_len); + + /* Directory is encrypted */ + err = fscrypt_fname_disk_to_usr(inode, + EXT4_DIRENT_HASH(de), + EXT4_DIRENT_MINOR_HASH(de), + &de_name, &fstr); + de_name = fstr; + fstr.len = save_len; + if (err) + goto errout; + if (!dir_emit(ctx, + de_name.name, de_name.len, + le32_to_cpu(de->inode), + get_dtype(sb, de->file_type))) + goto done; + } + } + ctx->pos += ext4_rec_len_from_disk(de->rec_len, + sb->s_blocksize); + } + if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode)) + goto done; + brelse(bh); + bh = NULL; + } +done: + err = 0; +errout: + fscrypt_fname_free_buffer(&fstr); + brelse(bh); + return err; +} + +static inline int is_32bit_api(void) +{ +#ifdef CONFIG_COMPAT + return in_compat_syscall(); +#else + return (BITS_PER_LONG == 32); +#endif +} + +/* + * These functions convert from the major/minor hash to an f_pos + * value for dx directories + * + * Upper layer (for example NFS) should specify FMODE_32BITHASH or + * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted + * directly on both 32-bit and 64-bit nodes, under such case, neither + * FMODE_32BITHASH nor FMODE_64BITHASH is specified. + */ +static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return major >> 1; + else + return ((__u64)(major >> 1) << 32) | (__u64)minor; +} + +static inline __u32 pos2maj_hash(struct file *filp, loff_t pos) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return (pos << 1) & 0xffffffff; + else + return ((pos >> 32) << 1) & 0xffffffff; +} + +static inline __u32 pos2min_hash(struct file *filp, loff_t pos) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return 0; + else + return pos & 0xffffffff; +} + +/* + * Return 32- or 64-bit end-of-file for dx directories + */ +static inline loff_t ext4_get_htree_eof(struct file *filp) +{ + if ((filp->f_mode & FMODE_32BITHASH) || + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) + return EXT4_HTREE_EOF_32BIT; + else + return EXT4_HTREE_EOF_64BIT; +} + + +/* + * ext4_dir_llseek() calls generic_file_llseek_size to handle htree + * directories, where the "offset" is in terms of the filename hash + * value instead of the byte offset. + * + * Because we may return a 64-bit hash that is well beyond offset limits, + * we need to pass the max hash as the maximum allowable offset in + * the htree directory case. + * + * For non-htree, ext4_llseek already chooses the proper max offset. + */ +static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + int dx_dir = is_dx_dir(inode); + loff_t ret, htree_max = ext4_get_htree_eof(file); + + if (likely(dx_dir)) + ret = generic_file_llseek_size(file, offset, whence, + htree_max, htree_max); + else + ret = ext4_llseek(file, offset, whence); + file->f_version = inode_peek_iversion(inode) - 1; + return ret; +} + +/* + * This structure holds the nodes of the red-black tree used to store + * the directory entry in hash order. + */ +struct fname { + __u32 hash; + __u32 minor_hash; + struct rb_node rb_hash; + struct fname *next; + __u32 inode; + __u8 name_len; + __u8 file_type; + char name[]; +}; + +/* + * This function implements a non-recursive way of freeing all of the + * nodes in the red-black tree. + */ +static void free_rb_tree_fname(struct rb_root *root) +{ + struct fname *fname, *next; + + rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash) + while (fname) { + struct fname *old = fname; + fname = fname->next; + kfree(old); + } + + *root = RB_ROOT; +} + + +static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp, + loff_t pos) +{ + struct dir_private_info *p; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return NULL; + p->curr_hash = pos2maj_hash(filp, pos); + p->curr_minor_hash = pos2min_hash(filp, pos); + return p; +} + +void ext4_htree_free_dir_info(struct dir_private_info *p) +{ + free_rb_tree_fname(&p->root); + kfree(p); +} + +/* + * Given a directory entry, enter it into the fname rb tree. + * + * When filename encryption is enabled, the dirent will hold the + * encrypted filename, while the htree will hold decrypted filename. + * The decrypted filename is passed in via ent_name. parameter. + */ +int ext4_htree_store_dirent(struct file *dir_file, __u32 hash, + __u32 minor_hash, + struct ext4_dir_entry_2 *dirent, + struct fscrypt_str *ent_name) +{ + struct rb_node **p, *parent = NULL; + struct fname *fname, *new_fn; + struct dir_private_info *info; + int len; + + info = dir_file->private_data; + p = &info->root.rb_node; + + /* Create and allocate the fname structure */ + len = sizeof(struct fname) + ent_name->len + 1; + new_fn = kzalloc(len, GFP_KERNEL); + if (!new_fn) + return -ENOMEM; + new_fn->hash = hash; + new_fn->minor_hash = minor_hash; + new_fn->inode = le32_to_cpu(dirent->inode); + new_fn->name_len = ent_name->len; + new_fn->file_type = dirent->file_type; + memcpy(new_fn->name, ent_name->name, ent_name->len); + + while (*p) { + parent = *p; + fname = rb_entry(parent, struct fname, rb_hash); + + /* + * If the hash and minor hash match up, then we put + * them on a linked list. This rarely happens... + */ + if ((new_fn->hash == fname->hash) && + (new_fn->minor_hash == fname->minor_hash)) { + new_fn->next = fname->next; + fname->next = new_fn; + return 0; + } + + if (new_fn->hash < fname->hash) + p = &(*p)->rb_left; + else if (new_fn->hash > fname->hash) + p = &(*p)->rb_right; + else if (new_fn->minor_hash < fname->minor_hash) + p = &(*p)->rb_left; + else /* if (new_fn->minor_hash > fname->minor_hash) */ + p = &(*p)->rb_right; + } + + rb_link_node(&new_fn->rb_hash, parent, p); + rb_insert_color(&new_fn->rb_hash, &info->root); + return 0; +} + + + +/* + * This is a helper function for ext4_dx_readdir. It calls filldir + * for all entries on the fname linked list. (Normally there is only + * one entry on the linked list, unless there are 62 bit hash collisions.) + */ +static int call_filldir(struct file *file, struct dir_context *ctx, + struct fname *fname) +{ + struct dir_private_info *info = file->private_data; + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + + if (!fname) { + ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: " + "called with null fname?!?", __func__, __LINE__, + inode->i_ino, current->comm); + return 0; + } + ctx->pos = hash2pos(file, fname->hash, fname->minor_hash); + while (fname) { + if (!dir_emit(ctx, fname->name, + fname->name_len, + fname->inode, + get_dtype(sb, fname->file_type))) { + info->extra_fname = fname; + return 1; + } + fname = fname->next; + } + return 0; +} + +static int ext4_dx_readdir(struct file *file, struct dir_context *ctx) +{ + struct dir_private_info *info = file->private_data; + struct inode *inode = file_inode(file); + struct fname *fname; + int ret = 0; + + if (!info) { + info = ext4_htree_create_dir_info(file, ctx->pos); + if (!info) + return -ENOMEM; + file->private_data = info; + } + + if (ctx->pos == ext4_get_htree_eof(file)) + return 0; /* EOF */ + + /* Some one has messed with f_pos; reset the world */ + if (info->last_pos != ctx->pos) { + free_rb_tree_fname(&info->root); + info->curr_node = NULL; + info->extra_fname = NULL; + info->curr_hash = pos2maj_hash(file, ctx->pos); + info->curr_minor_hash = pos2min_hash(file, ctx->pos); + } + + /* + * If there are any leftover names on the hash collision + * chain, return them first. + */ + if (info->extra_fname) { + if (call_filldir(file, ctx, info->extra_fname)) + goto finished; + info->extra_fname = NULL; + goto next_node; + } else if (!info->curr_node) + info->curr_node = rb_first(&info->root); + + while (1) { + /* + * Fill the rbtree if we have no more entries, + * or the inode has changed since we last read in the + * cached entries. + */ + if ((!info->curr_node) || + !inode_eq_iversion(inode, file->f_version)) { + info->curr_node = NULL; + free_rb_tree_fname(&info->root); + file->f_version = inode_query_iversion(inode); + ret = ext4_htree_fill_tree(file, info->curr_hash, + info->curr_minor_hash, + &info->next_hash); + if (ret < 0) + goto finished; + if (ret == 0) { + ctx->pos = ext4_get_htree_eof(file); + break; + } + info->curr_node = rb_first(&info->root); + } + + fname = rb_entry(info->curr_node, struct fname, rb_hash); + info->curr_hash = fname->hash; + info->curr_minor_hash = fname->minor_hash; + if (call_filldir(file, ctx, fname)) + break; + next_node: + info->curr_node = rb_next(info->curr_node); + if (info->curr_node) { + fname = rb_entry(info->curr_node, struct fname, + rb_hash); + info->curr_hash = fname->hash; + info->curr_minor_hash = fname->minor_hash; + } else { + if (info->next_hash == ~0) { + ctx->pos = ext4_get_htree_eof(file); + break; + } + info->curr_hash = info->next_hash; + info->curr_minor_hash = 0; + } + } +finished: + info->last_pos = ctx->pos; + return ret < 0 ? ret : 0; +} + +static int ext4_release_dir(struct inode *inode, struct file *filp) +{ + if (filp->private_data) + ext4_htree_free_dir_info(filp->private_data); + + return 0; +} + +int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf, + int buf_size) +{ + struct ext4_dir_entry_2 *de; + int rlen; + unsigned int offset = 0; + char *top; + + de = buf; + top = buf + buf_size; + while ((char *) de < top) { + if (ext4_check_dir_entry(dir, NULL, de, bh, + buf, buf_size, offset)) + return -EFSCORRUPTED; + rlen = ext4_rec_len_from_disk(de->rec_len, buf_size); + de = (struct ext4_dir_entry_2 *)((char *)de + rlen); + offset += rlen; + } + if ((char *) de > top) + return -EFSCORRUPTED; + + return 0; +} + +const struct file_operations ext4_dir_operations = { + .llseek = ext4_dir_llseek, + .read = generic_read_dir, + .iterate_shared = ext4_readdir, + .unlocked_ioctl = ext4_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = ext4_compat_ioctl, +#endif + .fsync = ext4_sync_file, + .release = ext4_release_dir, +}; -- cgit v1.2.3