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132 lines
3.3 KiB
132 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Squashfs - a compressed read only filesystem for Linux |
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* |
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* Copyright (c) 2010 |
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* Phillip Lougher <[email protected]> |
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* |
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* xattr_id.c |
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*/ |
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/* |
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* This file implements code to map the 32-bit xattr id stored in the inode |
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* into the on disk location of the xattr data. |
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*/ |
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#include <linux/fs.h> |
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#include <linux/vfs.h> |
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#include <linux/slab.h> |
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#include "squashfs_fs.h" |
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#include "squashfs_fs_sb.h" |
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#include "squashfs.h" |
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#include "xattr.h" |
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/* |
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* Map xattr id using the xattr id look up table |
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*/ |
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int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, |
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int *count, unsigned int *size, unsigned long long *xattr) |
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{ |
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struct squashfs_sb_info *msblk = sb->s_fs_info; |
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int block = SQUASHFS_XATTR_BLOCK(index); |
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int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index); |
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u64 start_block; |
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struct squashfs_xattr_id id; |
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int err; |
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if (index >= msblk->xattr_ids) |
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return -EINVAL; |
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start_block = le64_to_cpu(msblk->xattr_id_table[block]); |
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err = squashfs_read_metadata(sb, &id, &start_block, &offset, |
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sizeof(id)); |
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if (err < 0) |
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return err; |
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*xattr = le64_to_cpu(id.xattr); |
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*size = le32_to_cpu(id.size); |
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*count = le32_to_cpu(id.count); |
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return 0; |
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} |
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/* |
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* Read uncompressed xattr id lookup table indexes from disk into memory |
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*/ |
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__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start, |
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u64 *xattr_table_start, int *xattr_ids) |
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{ |
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struct squashfs_sb_info *msblk = sb->s_fs_info; |
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unsigned int len, indexes; |
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struct squashfs_xattr_id_table *id_table; |
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__le64 *table; |
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u64 start, end; |
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int n; |
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id_table = squashfs_read_table(sb, table_start, sizeof(*id_table)); |
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if (IS_ERR(id_table)) |
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return (__le64 *) id_table; |
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*xattr_table_start = le64_to_cpu(id_table->xattr_table_start); |
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*xattr_ids = le32_to_cpu(id_table->xattr_ids); |
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kfree(id_table); |
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/* Sanity check values */ |
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/* there is always at least one xattr id */ |
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if (*xattr_ids == 0) |
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return ERR_PTR(-EINVAL); |
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len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); |
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indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids); |
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/* |
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* The computed size of the index table (len bytes) should exactly |
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* match the table start and end points |
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*/ |
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start = table_start + sizeof(*id_table); |
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end = msblk->bytes_used; |
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if (len != (end - start)) |
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return ERR_PTR(-EINVAL); |
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table = squashfs_read_table(sb, start, len); |
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if (IS_ERR(table)) |
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return table; |
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/* table[0], table[1], ... table[indexes - 1] store the locations |
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* of the compressed xattr id blocks. Each entry should be less than |
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* the next (i.e. table[0] < table[1]), and the difference between them |
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* should be SQUASHFS_METADATA_SIZE or less. table[indexes - 1] |
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* should be less than table_start, and again the difference |
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* shouls be SQUASHFS_METADATA_SIZE or less. |
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* |
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* Finally xattr_table_start should be less than table[0]. |
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*/ |
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for (n = 0; n < (indexes - 1); n++) { |
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start = le64_to_cpu(table[n]); |
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end = le64_to_cpu(table[n + 1]); |
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if (start >= end || (end - start) > |
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(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) { |
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kfree(table); |
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return ERR_PTR(-EINVAL); |
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} |
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} |
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start = le64_to_cpu(table[indexes - 1]); |
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if (start >= table_start || (table_start - start) > |
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(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) { |
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kfree(table); |
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return ERR_PTR(-EINVAL); |
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} |
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if (*xattr_table_start >= le64_to_cpu(table[0])) { |
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kfree(table); |
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return ERR_PTR(-EINVAL); |
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} |
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return table; |
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}
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