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  */
zlib_inflate_blob(void * gunzip_buf,unsigned int sz,const void * buf,unsigned int len)9 int 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);
45 gunzip_nomem2:
46 	kfree(strm);
47 gunzip_nomem1:
48 	return rc; /* returns Z_OK (0) if successful */
49 }
50