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, windowBits: -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(objp: strm->workspace);
45gunzip_nomem2:
46 kfree(objp: strm);
47gunzip_nomem1:
48 return rc; /* returns Z_OK (0) if successful */
49}
50