1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2020, Microsoft Corporation.
4  *
5  *   Author(s): Steve French <stfrench@microsoft.com>
6  *              Suresh Jayaraman <sjayaraman@suse.de>
7  *              Jeff Layton <jlayton@kernel.org>
8  */
9 
10 #include <linux/fs.h>
11 #include <linux/slab.h>
12 #include <linux/inet.h>
13 #include <linux/ctype.h>
14 #include "cifsglob.h"
15 #include "cifsproto.h"
16 
17 /* extract the host portion of the UNC string */
extract_hostname(const char * unc)18 char *extract_hostname(const char *unc)
19 {
20 	const char *src;
21 	char *dst, *delim;
22 	unsigned int len;
23 
24 	/* skip double chars at beginning of string */
25 	/* BB: check validity of these bytes? */
26 	if (strlen(unc) < 3)
27 		return ERR_PTR(-EINVAL);
28 	for (src = unc; *src && *src == '\\'; src++)
29 		;
30 	if (!*src)
31 		return ERR_PTR(-EINVAL);
32 
33 	/* delimiter between hostname and sharename is always '\\' now */
34 	delim = strchr(src, '\\');
35 	if (!delim)
36 		return ERR_PTR(-EINVAL);
37 
38 	len = delim - src;
39 	dst = kmalloc((len + 1), GFP_KERNEL);
40 	if (dst == NULL)
41 		return ERR_PTR(-ENOMEM);
42 
43 	memcpy(dst, src, len);
44 	dst[len] = '\0';
45 
46 	return dst;
47 }
48 
extract_sharename(const char * unc)49 char *extract_sharename(const char *unc)
50 {
51 	const char *src;
52 	char *delim, *dst;
53 
54 	/* skip double chars at the beginning */
55 	src = unc + 2;
56 
57 	/* share name is always preceded by '\\' now */
58 	delim = strchr(src, '\\');
59 	if (!delim)
60 		return ERR_PTR(-EINVAL);
61 	delim++;
62 
63 	/* caller has to free the memory */
64 	dst = kstrdup(delim, GFP_KERNEL);
65 	if (!dst)
66 		return ERR_PTR(-ENOMEM);
67 
68 	return dst;
69 }
70