diff options
| -rw-r--r-- | lib/decompress_unlzo.c | 46 |
1 files changed, 41 insertions, 5 deletions
diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c index 855d9d30ec4..7eb3b80bf02 100644 --- a/lib/decompress_unlzo.c +++ b/lib/decompress_unlzo.c @@ -48,14 +48,25 @@ static const unsigned char lzop_magic[] = { #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 int INIT parse_header(u8 *input, u8 *skip) +STATIC inline int INIT parse_header(u8 *input, int *skip, int 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]) @@ -73,6 +84,15 @@ STATIC inline int INIT parse_header(u8 *input, u8 *skip) 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) @@ -80,6 +100,8 @@ STATIC inline int INIT parse_header(u8 *input, u8 *skip) 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; @@ -92,7 +114,8 @@ STATIC inline int INIT unlzo(u8 *input, int in_len, u8 *output, int *posp, void (*error) (char *x)) { - u8 skip = 0, r = 0; + u8 r = 0; + int skip = 0; u32 src_len, dst_len; size_t tmp; u8 *in_buf, *in_buf_save, *out_buf; @@ -134,19 +157,25 @@ STATIC inline int INIT unlzo(u8 *input, int in_len, if (fill) fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); - if (!parse_header(input, &skip)) { + if (!parse_header(input, &skip, in_len)) { error("invalid header"); goto exit_2; } in_buf += skip; + in_len -= skip; if (posp) *posp = skip; for (;;) { /* read uncompressed block size */ + 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) { @@ -161,10 +190,15 @@ STATIC inline int INIT unlzo(u8 *input, int in_len, } /* read compressed block size, and skip block checksum info */ + 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) { + if (src_len <= 0 || src_len > dst_len || src_len > in_len) { error("file corrupted"); goto exit_2; } @@ -196,8 +230,10 @@ STATIC inline int INIT unlzo(u8 *input, int in_len, if (fill) { in_buf = in_buf_save; fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); - } else + } else { in_buf += src_len; + in_len -= src_len; + } } ret = 0; |