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-rw-r--r--lib/decompress_unlzo.c131
1 files changed, 106 insertions, 25 deletions
diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c
index db521f45626..960183d4258 100644
--- a/lib/decompress_unlzo.c
+++ b/lib/decompress_unlzo.c
@@ -31,9 +31,8 @@
*/
#ifdef STATIC
-#include "lzo/lzo1x_decompress.c"
+#include "lzo/lzo1x_decompress_safe.c"
#else
-#include <linux/slab.h>
#include <linux/decompress/unlzo.h>
#endif
@@ -49,14 +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])
@@ -74,6 +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)
@@ -81,6 +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;
@@ -91,15 +112,14 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
int (*fill) (void *, unsigned int),
int (*flush) (void *, unsigned int),
u8 *output, int *posp,
- void (*error_fn) (char *x))
+ 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;
- int obytes_processed = 0;
-
- set_error_fn(error_fn);
+ int ret = -1;
if (output) {
out_buf = output;
@@ -119,8 +139,8 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
goto exit_1;
} else if (input) {
in_buf = input;
- } else if (!fill || !posp) {
- error("NULL input pointer and missing position pointer or fill function");
+ } else if (!fill) {
+ error("NULL input pointer and missing fill function");
goto exit_1;
} else {
in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
@@ -134,22 +154,47 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
if (posp)
*posp = 0;
- if (fill)
- fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
+ 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(input, &skip)) {
+ 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) {
@@ -164,8 +209,18 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
}
/* 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");
@@ -173,37 +228,63 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
}
/* 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;
- r = lzo1x_decompress_safe((u8 *) in_buf, src_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 (r != LZO_E_OK || dst_len != tmp) {
+ error("Compressed data violation");
+ goto exit_2;
+ }
}
- obytes_processed += dst_len;
- if (flush)
- flush(out_buf, 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;
- fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
- } else
- in_buf += src_len;
+ }
}
+ ret = 0;
exit_2:
if (!input)
- free(in_buf);
+ free(in_buf_save);
exit_1:
if (!output)
free(out_buf);
exit:
- return obytes_processed;
+ return ret;
}
#define decompress unlzo
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-10 07:55:06 +0000