cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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xz_wrapper.c (3847B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Squashfs - a compressed read only filesystem for Linux
      4 *
      5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
      6 * Phillip Lougher <phillip@squashfs.org.uk>
      7 *
      8 * xz_wrapper.c
      9 */
     10
     11
     12#include <linux/mutex.h>
     13#include <linux/bio.h>
     14#include <linux/slab.h>
     15#include <linux/xz.h>
     16#include <linux/bitops.h>
     17
     18#include "squashfs_fs.h"
     19#include "squashfs_fs_sb.h"
     20#include "squashfs.h"
     21#include "decompressor.h"
     22#include "page_actor.h"
     23
     24struct squashfs_xz {
     25	struct xz_dec *state;
     26	struct xz_buf buf;
     27};
     28
     29struct disk_comp_opts {
     30	__le32 dictionary_size;
     31	__le32 flags;
     32};
     33
     34struct comp_opts {
     35	int dict_size;
     36};
     37
     38static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
     39	void *buff, int len)
     40{
     41	struct disk_comp_opts *comp_opts = buff;
     42	struct comp_opts *opts;
     43	int err = 0, n;
     44
     45	opts = kmalloc(sizeof(*opts), GFP_KERNEL);
     46	if (opts == NULL) {
     47		err = -ENOMEM;
     48		goto out2;
     49	}
     50
     51	if (comp_opts) {
     52		/* check compressor options are the expected length */
     53		if (len < sizeof(*comp_opts)) {
     54			err = -EIO;
     55			goto out;
     56		}
     57
     58		opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
     59
     60		/* the dictionary size should be 2^n or 2^n+2^(n+1) */
     61		n = ffs(opts->dict_size) - 1;
     62		if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
     63						(1 << (n + 1))) {
     64			err = -EIO;
     65			goto out;
     66		}
     67	} else
     68		/* use defaults */
     69		opts->dict_size = max_t(int, msblk->block_size,
     70							SQUASHFS_METADATA_SIZE);
     71
     72	return opts;
     73
     74out:
     75	kfree(opts);
     76out2:
     77	return ERR_PTR(err);
     78}
     79
     80
     81static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
     82{
     83	struct comp_opts *comp_opts = buff;
     84	struct squashfs_xz *stream;
     85	int err;
     86
     87	stream = kmalloc(sizeof(*stream), GFP_KERNEL);
     88	if (stream == NULL) {
     89		err = -ENOMEM;
     90		goto failed;
     91	}
     92
     93	stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
     94	if (stream->state == NULL) {
     95		kfree(stream);
     96		err = -ENOMEM;
     97		goto failed;
     98	}
     99
    100	return stream;
    101
    102failed:
    103	ERROR("Failed to initialise xz decompressor\n");
    104	return ERR_PTR(err);
    105}
    106
    107
    108static void squashfs_xz_free(void *strm)
    109{
    110	struct squashfs_xz *stream = strm;
    111
    112	if (stream) {
    113		xz_dec_end(stream->state);
    114		kfree(stream);
    115	}
    116}
    117
    118
    119static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
    120	struct bio *bio, int offset, int length,
    121	struct squashfs_page_actor *output)
    122{
    123	struct bvec_iter_all iter_all = {};
    124	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
    125	int total = 0, error = 0;
    126	struct squashfs_xz *stream = strm;
    127
    128	xz_dec_reset(stream->state);
    129	stream->buf.in_pos = 0;
    130	stream->buf.in_size = 0;
    131	stream->buf.out_pos = 0;
    132	stream->buf.out_size = PAGE_SIZE;
    133	stream->buf.out = squashfs_first_page(output);
    134
    135	for (;;) {
    136		enum xz_ret xz_err;
    137
    138		if (stream->buf.in_pos == stream->buf.in_size) {
    139			const void *data;
    140			int avail;
    141
    142			if (!bio_next_segment(bio, &iter_all)) {
    143				/* XZ_STREAM_END must be reached. */
    144				error = -EIO;
    145				break;
    146			}
    147
    148			avail = min(length, ((int)bvec->bv_len) - offset);
    149			data = bvec_virt(bvec);
    150			length -= avail;
    151			stream->buf.in = data + offset;
    152			stream->buf.in_size = avail;
    153			stream->buf.in_pos = 0;
    154			offset = 0;
    155		}
    156
    157		if (stream->buf.out_pos == stream->buf.out_size) {
    158			stream->buf.out = squashfs_next_page(output);
    159			if (stream->buf.out != NULL) {
    160				stream->buf.out_pos = 0;
    161				total += PAGE_SIZE;
    162			}
    163		}
    164
    165		xz_err = xz_dec_run(stream->state, &stream->buf);
    166		if (xz_err == XZ_STREAM_END)
    167			break;
    168		if (xz_err != XZ_OK) {
    169			error = -EIO;
    170			break;
    171		}
    172	}
    173
    174	squashfs_finish_page(output);
    175
    176	return error ? error : total + stream->buf.out_pos;
    177}
    178
    179const struct squashfs_decompressor squashfs_xz_comp_ops = {
    180	.init = squashfs_xz_init,
    181	.comp_opts = squashfs_xz_comp_opts,
    182	.free = squashfs_xz_free,
    183	.decompress = squashfs_xz_uncompress,
    184	.id = XZ_COMPRESSION,
    185	.name = "xz",
    186	.supported = 1
    187};