diff options
Diffstat (limited to 'lib/decompress_unlzo.c')
| -rw-r--r-- | lib/decompress_unlzo.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c new file mode 100644 index 000000000..1f439a622 --- /dev/null +++ b/lib/decompress_unlzo.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LZO decompressor for the Linux kernel. Code borrowed from the lzo + * implementation by Markus Franz Xaver Johannes Oberhumer. + * + * Linux kernel adaptation: + * Copyright (C) 2009 + * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com> + * + * Original code: + * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer + * All Rights Reserved. + * + * Markus F.X.J. Oberhumer + * <markus@oberhumer.com> + * http://www.oberhumer.com/opensource/lzop/ + */ + +#ifdef STATIC +#define PREBOOT +#include "lzo/lzo1x_decompress_safe.c" +#else +#include <linux/decompress/unlzo.h> +#endif + +#include <linux/types.h> +#include <linux/lzo.h> +#include <linux/decompress/mm.h> + +#include <linux/compiler.h> +#include <asm/unaligned.h> + +static const unsigned char lzop_magic[] = { + 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a }; + +#define LZO_BLOCK_SIZE (256*1024l) +#define HEADER_HAS_FILTER 0x00000800L +#define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4) +#define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4) + +STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len) +{ + int l; + u8 *parse = input; + u8 *end = input + in_len; + u8 level = 0; + u16 version; + + /* + * Check that there's enough input to possibly have a valid header. + * Then it is possible to parse several fields until the minimum + * size may have been used. + */ + if (in_len < HEADER_SIZE_MIN) + return 0; + + /* read magic: 9 first bits */ + for (l = 0; l < 9; l++) { + if (*parse++ != lzop_magic[l]) + return 0; + } + /* get version (2bytes), skip library version (2), + * 'need to be extracted' version (2) and + * method (1) */ + version = get_unaligned_be16(parse); + parse += 7; + if (version >= 0x0940) + level = *parse++; + if (get_unaligned_be32(parse) & HEADER_HAS_FILTER) + parse += 8; /* flags + filter info */ + else + parse += 4; /* flags */ + + /* + * At least mode, mtime_low, filename length, and checksum must + * be left to be parsed. If also mtime_high is present, it's OK + * because the next input buffer check is after reading the + * filename length. + */ + if (end - parse < 8 + 1 + 4) + return 0; + + /* skip mode and mtime_low */ + parse += 8; + if (version >= 0x0940) + parse += 4; /* skip mtime_high */ + + l = *parse++; + /* don't care about the file name, and skip checksum */ + if (end - parse < l + 4) + return 0; + parse += l + 4; + + *skip = parse - input; + return 1; +} + +STATIC int INIT unlzo(u8 *input, long in_len, + long (*fill)(void *, unsigned long), + long (*flush)(void *, unsigned long), + u8 *output, long *posp, + void (*error) (char *x)) +{ + u8 r = 0; + long skip = 0; + u32 src_len, dst_len; + size_t tmp; + u8 *in_buf, *in_buf_save, *out_buf; + int ret = -1; + + if (output) { + out_buf = output; + } else if (!flush) { + error("NULL output pointer and no flush function provided"); + goto exit; + } else { + out_buf = malloc(LZO_BLOCK_SIZE); + if (!out_buf) { + error("Could not allocate output buffer"); + goto exit; + } + } + + if (input && fill) { + error("Both input pointer and fill function provided, don't know what to do"); + goto exit_1; + } else if (input) { + in_buf = input; + } else if (!fill) { + error("NULL input pointer and missing fill function"); + goto exit_1; + } else { + in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE)); + if (!in_buf) { + error("Could not allocate input buffer"); + goto exit_1; + } + } + in_buf_save = in_buf; + + if (posp) + *posp = 0; + + if (fill) { + /* + * Start from in_buf + HEADER_SIZE_MAX to make it possible + * to use memcpy() to copy the unused data to the beginning + * of the buffer. This way memmove() isn't needed which + * is missing from pre-boot environments of most archs. + */ + in_buf += HEADER_SIZE_MAX; + in_len = fill(in_buf, HEADER_SIZE_MAX); + } + + if (!parse_header(in_buf, &skip, in_len)) { + error("invalid header"); + goto exit_2; + } + in_buf += skip; + in_len -= skip; + + if (fill) { + /* Move the unused data to the beginning of the buffer. */ + memcpy(in_buf_save, in_buf, in_len); + in_buf = in_buf_save; + } + + if (posp) + *posp = skip; + + for (;;) { + /* read uncompressed block size */ + if (fill && in_len < 4) { + skip = fill(in_buf + in_len, 4 - in_len); + if (skip > 0) + in_len += skip; + } + if (in_len < 4) { + error("file corrupted"); + goto exit_2; + } + dst_len = get_unaligned_be32(in_buf); + in_buf += 4; + in_len -= 4; + + /* exit if last block */ + if (dst_len == 0) { + if (posp) + *posp += 4; + break; + } + + if (dst_len > LZO_BLOCK_SIZE) { + error("dest len longer than block size"); + goto exit_2; + } + + /* read compressed block size, and skip block checksum info */ + if (fill && in_len < 8) { + skip = fill(in_buf + in_len, 8 - in_len); + if (skip > 0) + in_len += skip; + } + if (in_len < 8) { + error("file corrupted"); + goto exit_2; + } + src_len = get_unaligned_be32(in_buf); + in_buf += 8; + in_len -= 8; + + if (src_len <= 0 || src_len > dst_len) { + error("file corrupted"); + goto exit_2; + } + + /* decompress */ + if (fill && in_len < src_len) { + skip = fill(in_buf + in_len, src_len - in_len); + if (skip > 0) + in_len += skip; + } + if (in_len < src_len) { + error("file corrupted"); + goto exit_2; + } + tmp = dst_len; + + /* When the input data is not compressed at all, + * lzo1x_decompress_safe will fail, so call memcpy() + * instead */ + if (unlikely(dst_len == src_len)) + memcpy(out_buf, in_buf, src_len); + else { + r = lzo1x_decompress_safe((u8 *) in_buf, src_len, + out_buf, &tmp); + + if (r != LZO_E_OK || dst_len != tmp) { + error("Compressed data violation"); + goto exit_2; + } + } + + if (flush && flush(out_buf, dst_len) != dst_len) + goto exit_2; + if (output) + out_buf += dst_len; + if (posp) + *posp += src_len + 12; + + in_buf += src_len; + in_len -= src_len; + if (fill) { + /* + * If there happens to still be unused data left in + * in_buf, move it to the beginning of the buffer. + * Use a loop to avoid memmove() dependency. + */ + if (in_len > 0) + for (skip = 0; skip < in_len; ++skip) + in_buf_save[skip] = in_buf[skip]; + in_buf = in_buf_save; + } + } + + ret = 0; +exit_2: + if (!input) + free(in_buf_save); +exit_1: + if (!output) + free(out_buf); +exit: + return ret; +} + +#ifdef PREBOOT +STATIC int INIT __decompress(unsigned char *buf, long len, + long (*fill)(void*, unsigned long), + long (*flush)(void*, unsigned long), + unsigned char *out_buf, long olen, + long *pos, + void (*error)(char *x)) +{ + return unlzo(buf, len, fill, flush, out_buf, pos, error); +} +#endif |