1/*
2   Unix SMB/CIFS implementation.
3   Username handling
4   Copyright (C) Andrew Tridgell 1992-1998
5   Copyright (C) Jeremy Allison 1997-2001.
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 3 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program.  If not, see <http://www.gnu.org/licenses/>.
19*/
20
21#include "includes.h"
22
23/* internal functions */
24static struct passwd *uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
25						struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
26						int N);
27static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx, int offset,
28						 struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
29						 int N);
30
31/****************************************************************************
32 Get a users home directory.
33****************************************************************************/
34
35char *get_user_home_dir(TALLOC_CTX *mem_ctx, const char *user)
36{
37	struct passwd *pass;
38	char *result;
39
40	/* Ensure the user exists. */
41
42	pass = Get_Pwnam_alloc(mem_ctx, user);
43
44	if (!pass)
45		return(NULL);
46
47	/* Return home directory from struct passwd. */
48
49	result = talloc_move(mem_ctx, &pass->pw_dir);
50
51	TALLOC_FREE(pass);
52	return result;
53}
54
55/****************************************************************************
56 * A wrapper for sys_getpwnam().  The following variations are tried:
57 *   - as transmitted
58 *   - in all lower case if this differs from transmitted
59 *   - in all upper case if this differs from transmitted
60 *   - using lp_usernamelevel() for permutations.
61****************************************************************************/
62
63static struct passwd *Get_Pwnam_internals(TALLOC_CTX *mem_ctx,
64					  const char *user, char *user2)
65{
66	struct passwd *ret = NULL;
67
68	if (!user2 || !(*user2))
69		return(NULL);
70
71	if (!user || !(*user))
72		return(NULL);
73
74	/* Try in all lower case first as this is the most
75	   common case on UNIX systems */
76	strlower_m(user2);
77	DEBUG(5,("Trying _Get_Pwnam(), username as lowercase is %s\n",user2));
78	ret = getpwnam_alloc(mem_ctx, user2);
79	if(ret)
80		goto done;
81
82	/* Try as given, if username wasn't originally lowercase */
83	if(strcmp(user, user2) != 0) {
84		DEBUG(5,("Trying _Get_Pwnam(), username as given is %s\n",
85			 user));
86		ret = getpwnam_alloc(mem_ctx, user);
87		if(ret)
88			goto done;
89	}
90
91	/* Try as uppercase, if username wasn't originally uppercase */
92	strupper_m(user2);
93	if(strcmp(user, user2) != 0) {
94		DEBUG(5,("Trying _Get_Pwnam(), username as uppercase is %s\n",
95			 user2));
96		ret = getpwnam_alloc(mem_ctx, user2);
97		if(ret)
98			goto done;
99	}
100
101	/* Try all combinations up to usernamelevel */
102	strlower_m(user2);
103	DEBUG(5,("Checking combinations of %d uppercase letters in %s\n",
104		 lp_usernamelevel(), user2));
105	ret = uname_string_combinations(user2, mem_ctx, getpwnam_alloc,
106					lp_usernamelevel());
107
108done:
109	DEBUG(5,("Get_Pwnam_internals %s find user [%s]!\n",ret ?
110		 "did":"didn't", user));
111
112	return ret;
113}
114
115/****************************************************************************
116 Get_Pwnam wrapper without modification.
117  NOTE: This with NOT modify 'user'!
118  This will return an allocated structure
119****************************************************************************/
120
121struct passwd *Get_Pwnam_alloc(TALLOC_CTX *mem_ctx, const char *user)
122{
123	fstring user2;
124	struct passwd *ret;
125
126	if ( *user == '\0' ) {
127		DEBUG(10,("Get_Pwnam: empty username!\n"));
128		return NULL;
129	}
130
131	fstrcpy(user2, user);
132
133	DEBUG(5,("Finding user %s\n", user));
134
135	ret = Get_Pwnam_internals(mem_ctx, user, user2);
136
137	return ret;
138}
139
140/* The functions below have been taken from password.c and slightly modified */
141/****************************************************************************
142 Apply a function to upper/lower case combinations
143 of a string and return true if one of them returns true.
144 Try all combinations with N uppercase letters.
145 offset is the first char to try and change (start with 0)
146 it assumes the string starts lowercased
147****************************************************************************/
148
149static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx,
150						 int offset,
151						 struct passwd *(*fn)(TALLOC_CTX *mem_ctx, const char *),
152						 int N)
153{
154	ssize_t len = (ssize_t)strlen(s);
155	int i;
156	struct passwd *ret;
157
158	if (N <= 0 || offset >= len)
159		return(fn(mem_ctx, s));
160
161	for (i=offset;i<(len-(N-1));i++) {
162		char c = s[i];
163		if (!islower_ascii((int)c))
164			continue;
165		s[i] = toupper_ascii(c);
166		ret = uname_string_combinations2(s, mem_ctx, i+1, fn, N-1);
167		if(ret)
168			return(ret);
169		s[i] = c;
170	}
171	return(NULL);
172}
173
174/****************************************************************************
175 Apply a function to upper/lower case combinations
176 of a string and return true if one of them returns true.
177 Try all combinations with up to N uppercase letters.
178 offset is the first char to try and change (start with 0)
179 it assumes the string starts lowercased
180****************************************************************************/
181
182static struct passwd * uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
183						 struct passwd * (*fn)(TALLOC_CTX *mem_ctx, const char *),
184						 int N)
185{
186	int n;
187	struct passwd *ret;
188
189	for (n=1;n<=N;n++) {
190		ret = uname_string_combinations2(s,mem_ctx,0,fn,n);
191		if(ret)
192			return(ret);
193	}
194	return(NULL);
195}
196
197