1#include <linux/zutil.h>
2#include <linux/errno.h>
3#include <linux/slab.h>
4#include <linux/vmalloc.h>
5
6/* Utility function: initialize zlib, unpack binary blob, clean up zlib,
7 * return len or negative error code.
8 */
9int zlib_inflate_blob(void *gunzip_buf, unsigned int sz,
10		      const void *buf, unsigned int len)
11{
12	const u8 *zbuf = buf;
13	struct z_stream_s *strm;
14	int rc;
15
16	rc = -ENOMEM;
17	strm = kmalloc(sizeof(*strm), GFP_KERNEL);
18	if (strm == NULL)
19		goto gunzip_nomem1;
20	strm->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
21	if (strm->workspace == NULL)
22		goto gunzip_nomem2;
23
24	/* gzip header (1f,8b,08... 10 bytes total + possible asciz filename)
25	 * expected to be stripped from input
26	 */
27	strm->next_in = zbuf;
28	strm->avail_in = len;
29	strm->next_out = gunzip_buf;
30	strm->avail_out = sz;
31
32	rc = zlib_inflateInit2(strm, -MAX_WBITS);
33	if (rc == Z_OK) {
34		rc = zlib_inflate(strm, Z_FINISH);
35		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
36		if (rc == Z_STREAM_END)
37			rc = sz - strm->avail_out;
38		else
39			rc = -EINVAL;
40		zlib_inflateEnd(strm);
41	} else
42		rc = -EINVAL;
43
44	kfree(strm->workspace);
45gunzip_nomem2:
46	kfree(strm);
47gunzip_nomem1:
48	return rc; /* returns Z_OK (0) if successful */
49}
50