summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--delta.h5
-rw-r--r--patch-delta.c26
-rw-r--r--sha1_file.c6
3 files changed, 28 insertions, 9 deletions
diff --git a/delta.h b/delta.h
index a15350d..9464f3e 100644
--- a/delta.h
+++ b/delta.h
@@ -16,7 +16,8 @@ extern void *patch_delta(void *src_buf, unsigned long src_size,
* This must be called twice on the delta data buffer, first to get the
* expected reference buffer size, and again to get the result buffer size.
*/
-static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
+static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
+ const unsigned char *top)
{
const unsigned char *data = *datap;
unsigned char cmd;
@@ -26,7 +27,7 @@ static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
cmd = *data++;
size |= (cmd & ~0x80) << i;
i += 7;
- } while (cmd & 0x80);
+ } while (cmd & 0x80 && data < top);
*datap = data;
return size;
}
diff --git a/patch-delta.c b/patch-delta.c
index c0e1311..d95f0d9 100644
--- a/patch-delta.c
+++ b/patch-delta.c
@@ -28,12 +28,12 @@ void *patch_delta(void *src_buf, unsigned long src_size,
top = delta_buf + delta_size;
/* make sure the orig file size matches what we expect */
- size = get_delta_hdr_size(&data);
+ size = get_delta_hdr_size(&data, top);
if (size != src_size)
return NULL;
/* now the result size */
- size = get_delta_hdr_size(&data);
+ size = get_delta_hdr_size(&data, top);
dst_buf = malloc(size + 1);
if (!dst_buf)
return NULL;
@@ -52,21 +52,37 @@ void *patch_delta(void *src_buf, unsigned long src_size,
if (cmd & 0x20) cp_size |= (*data++ << 8);
if (cmd & 0x40) cp_size |= (*data++ << 16);
if (cp_size == 0) cp_size = 0x10000;
+ if (cp_off + cp_size < cp_size ||
+ cp_off + cp_size > src_size ||
+ cp_size > size)
+ goto bad;
memcpy(out, src_buf + cp_off, cp_size);
out += cp_size;
- } else {
+ size -= cp_size;
+ } else if (cmd) {
+ if (cmd > size)
+ goto bad;
memcpy(out, data, cmd);
out += cmd;
data += cmd;
+ size -= cmd;
+ } else {
+ /*
+ * cmd == 0 is reserved for future encoding
+ * extensions. In the mean time we must fail when
+ * encountering them (might be data corruption).
+ */
+ goto bad;
}
}
/* sanity check */
- if (data != top || out - dst_buf != size) {
+ if (data != top || size != 0) {
+ bad:
free(dst_buf);
return NULL;
}
- *dst_size = size;
+ *dst_size = out - dst_buf;
return dst_buf;
}
diff --git a/sha1_file.c b/sha1_file.c
index ba8c4f7..e3d0113 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -808,10 +808,12 @@ static int packed_delta_info(unsigned char *base_sha1,
* the result size.
*/
data = delta_head;
- get_delta_hdr_size(&data); /* ignore base size */
+
+ /* ignore base size */
+ get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
/* Read the result size */
- result_size = get_delta_hdr_size(&data);
+ result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
*sizep = result_size;
}
return 0;