f3065f60dd
Sizing the buffer using block size alone is incorrect leading to a potential buffer over-run on 4K block size file systems (because the metadata block size is always 8K). Srclength is set to the maximum expected size of the decompressed block and it is block_size or 8K depending on whether a data or metadata block is being decompressed. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2010 LG Electronics
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* Chan Jeong <chan.jeong@lge.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* lzo_wrapper.c
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*/
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#include <linux/mutex.h>
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#include <linux/buffer_head.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/lzo.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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#include "decompressor.h"
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struct squashfs_lzo {
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void *input;
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void *output;
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};
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static void *lzo_init(struct squashfs_sb_info *msblk)
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{
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int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
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struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
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if (stream == NULL)
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goto failed;
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stream->input = vmalloc(block_size);
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if (stream->input == NULL)
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goto failed;
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stream->output = vmalloc(block_size);
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if (stream->output == NULL)
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goto failed2;
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return stream;
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failed2:
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vfree(stream->input);
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failed:
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ERROR("Failed to allocate lzo workspace\n");
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kfree(stream);
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return NULL;
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}
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static void lzo_free(void *strm)
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{
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struct squashfs_lzo *stream = strm;
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if (stream) {
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vfree(stream->input);
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vfree(stream->output);
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}
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kfree(stream);
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}
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static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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struct buffer_head **bh, int b, int offset, int length, int srclength,
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int pages)
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{
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struct squashfs_lzo *stream = msblk->stream;
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void *buff = stream->input;
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int avail, i, bytes = length, res;
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size_t out_len = srclength;
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mutex_lock(&msblk->read_data_mutex);
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for (i = 0; i < b; i++) {
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wait_on_buffer(bh[i]);
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if (!buffer_uptodate(bh[i]))
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goto block_release;
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avail = min(bytes, msblk->devblksize - offset);
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memcpy(buff, bh[i]->b_data + offset, avail);
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buff += avail;
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bytes -= avail;
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offset = 0;
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put_bh(bh[i]);
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}
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res = lzo1x_decompress_safe(stream->input, (size_t)length,
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stream->output, &out_len);
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if (res != LZO_E_OK)
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goto failed;
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res = bytes = (int)out_len;
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for (i = 0, buff = stream->output; bytes && i < pages; i++) {
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avail = min_t(int, bytes, PAGE_CACHE_SIZE);
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memcpy(buffer[i], buff, avail);
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buff += avail;
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bytes -= avail;
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}
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mutex_unlock(&msblk->read_data_mutex);
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return res;
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block_release:
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for (; i < b; i++)
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put_bh(bh[i]);
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failed:
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mutex_unlock(&msblk->read_data_mutex);
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ERROR("lzo decompression failed, data probably corrupt\n");
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return -EIO;
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}
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const struct squashfs_decompressor squashfs_lzo_comp_ops = {
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.init = lzo_init,
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.free = lzo_free,
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.decompress = lzo_uncompress,
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.id = LZO_COMPRESSION,
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.name = "lzo",
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.supported = 1
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};
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