[PATCH] fix unlzo support
Sascha Hauer
s.hauer at pengutronix.de
Thu Nov 17 16:36:52 EST 2011
unlzo support is broken for files > 256k (more than one block)
since commit a3463cc12877f6527624972c190a80ebb787a604
(lib/decompress_unlzo: use fill and full to read and write data)
This patch updates unlzo support to the latest version of the kernel
plus a small buffer free fix.
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
lib/decompress_unlzo.c | 216 ++++++++++++++++++++++++++++++++++++------------
1 files changed, 162 insertions(+), 54 deletions(-)
diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c
index fc5c49f..0ae3d4d 100644
--- a/lib/decompress_unlzo.c
+++ b/lib/decompress_unlzo.c
@@ -46,14 +46,25 @@ 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 parse_header(u8 *input, u8 *skip)
+static inline int 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])
@@ -71,6 +82,15 @@ static inline int 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)
@@ -78,108 +98,191 @@ static inline int 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;
return 1;
}
-static int __unlzo(int *dest_len,
- int (*fill) (void *, unsigned int),
- int (*flush) (void *, unsigned int))
+static inline int __unlzo(u8 *input, int in_len,
+ int (*fill) (void *, unsigned int),
+ int (*flush) (void *, unsigned int),
+ 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, *out_buf_save;
- int obytes_processed = 0;
+ u8 *in_buf, *in_buf_save, *out_buf;
int ret = -1;
- out_buf = xmalloc(LZO_BLOCK_SIZE);
- in_buf = xmalloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
+ 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;
- out_buf_save = out_buf;
- ret = fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
- if (ret < 0)
- goto exit_free;
-
- if (!parse_header(in_buf, &skip))
- return -EINVAL;
+ 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 (dst_len == 0) {
+ if (posp)
+ *posp += 4;
break;
+ }
if (dst_len > LZO_BLOCK_SIZE) {
- printf("dest len longer than block size");
- goto exit_free;
+ 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) {
- printf("file corrupted");
- goto exit_free;
+ 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)) {
- if (src_len != dst_len) {
- printf("Compressed data violation");
- goto exit_free;
- }
- out_buf = in_buf;
- } else {
+ 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) {
- printf("Compressed data violation");
- goto exit_free;
+ error("Compressed data violation");
+ goto exit_2;
}
}
- ret = flush(out_buf, dst_len);
- if (ret < 0)
- goto exit_free;
-
- out_buf = in_buf + src_len;
- in_buf = in_buf_save;
- ret = fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
- if (ret < 0)
- goto exit_free;
-
- if (ret == 0)
- in_buf = out_buf;
-
- out_buf = out_buf_save;
-
- obytes_processed += dst_len;
-
+ 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;
+ }
}
-exit_free:
- free(in_buf);
- free(out_buf);
-
- *dest_len = obytes_processed;
- return 0;
+ ret = 0;
+exit_2:
+ if (!input)
+ free(in_buf_save);
+exit_1:
+ if (!output)
+ free(out_buf);
+exit:
+ return ret;
}
static int in_fd;
@@ -195,9 +298,14 @@ static int unlzo_flush(void *buf, unsigned int len)
return write(out_fd, buf, len);
}
+static void unlzo_error(char *s)
+{
+ printf("%s\n", s);
+}
+
int unlzo(int _in_fd, int _out_fd, int *dest_len)
{
in_fd = _in_fd;
out_fd = _out_fd;
- return __unlzo(dest_len, unlzo_fill, unlzo_flush);
+ return __unlzo(NULL, 0, unlzo_fill, unlzo_flush, NULL, NULL, unlzo_error);
}
--
1.7.7.1
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