[PATCH] Decompressors: Check input size in decompress_inflate.c

From: Lasse Collin
Date: Fri Nov 26 2010 - 13:23:28 EST


From: Lasse Collin <lasse.collin@xxxxxxxxxxx>

Check for end of the input buffer when skipping over
the filename field in the .gz file header.

Signed-off-by: Lasse Collin <lasse.collin@xxxxxxxxxxx>
---

diff -uprN linux-2.6.37-rc3.orig/lib/decompress_inflate.c linux-2.6.37-rc3/lib/decompress_inflate.c
--- linux-2.6.37-rc3.orig/lib/decompress_inflate.c 2010-10-20 23:30:22.000000000 +0300
+++ linux-2.6.37-rc3/lib/decompress_inflate.c 2010-11-26 19:42:15.000000000 +0200
@@ -100,13 +100,22 @@ STATIC int INIT gunzip(unsigned char *bu
* possible asciz filename)
*/
strm->next_in = zbuf + 10;
+ strm->avail_in = len - 10;
/* skip over asciz filename */
if (zbuf[3] & 0x8) {
- while (strm->next_in[0])
- strm->next_in++;
- strm->next_in++;
+ do {
+ /*
+ * If the filename doesn't fit into the buffer,
+ * the file is very probably corrupt. Don't try
+ * to read more data.
+ */
+ if (strm->avail_in == 0) {
+ error("header error");
+ goto gunzip_5;
+ }
+ --strm->avail_in;
+ } while (*strm->next_in++);
}
- strm->avail_in = len - (strm->next_in - zbuf);

strm->next_out = out_buf;
strm->avail_out = out_len;
--
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