1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/* Copyright (C) 2005, 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <shlib-compat.h>
#include <bp-checks.h>
#include <linux/posix_types.h>
#include <kernel-features.h>
/*
In Linux 2.1.x the chown functions have been changed. A new function lchown
was introduced. The new chown now follows symlinks - the old chown and the
new lchown do not follow symlinks.
The new lchown function has the same number as the old chown had and the
new chown has a new number. When compiling with headers from Linux > 2.1.8x
it's impossible to run this libc with older kernels. In these cases libc
has therefore to route calls to chown to the old chown function.
*/
extern int __chown_is_lchown (const char *__file, uid_t __owner,
gid_t __group);
extern int __real_chown (const char *__file, uid_t __owner, gid_t __group);
#if defined __NR_lchown || __ASSUME_LCHOWN_SYSCALL > 0
/* Running under Linux > 2.1.80. */
# ifdef __NR_chown32
# if __ASSUME_32BITUIDS == 0
/* This variable is shared with all files that need to check for 32bit
uids. */
extern int __libc_missing_32bit_uids;
# endif
# endif /* __NR_chown32 */
#endif
int
fchownat (int fd, const char *file, uid_t owner, gid_t group, int flag)
{
if (flag & ~AT_SYMLINK_NOFOLLOW)
{
__set_errno (EINVAL);
return -1;
}
char *buf = NULL;
if (fd != AT_FDCWD && file[0] != '/')
{
size_t filelen = strlen (file);
static const char procfd[] = "/proc/self/fd/%d/%s";
/* Buffer for the path name we are going to use. It consists of
- the string /proc/self/fd/
- the file descriptor number
- the file name provided.
The final NUL is included in the sizeof. A bit of overhead
due to the format elements compensates for possible negative
numbers. */
size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
buf = alloca (buflen);
__snprintf (buf, buflen, procfd, fd, file);
file = buf;
}
int result;
INTERNAL_SYSCALL_DECL (err);
#if defined __NR_lchown || __ASSUME_LCHOWN_SYSCALL > 0
# if __ASSUME_LCHOWN_SYSCALL == 0
static int __libc_old_chown;
# ifdef __NR_chown32
if (__libc_missing_32bit_uids <= 0)
{
if (flag & AT_SYMLINK_NOFOLLOW)
result = INTERNAL_SYSCALL (lchown32, err, 3, CHECK_STRING (file),
owner, group);
else
result = INTERNAL_SYSCALL (chown32, err, 3, CHECK_STRING (file),
owner, group);
if (!INTERNAL_SYSCALL_ERROR_P (result, err))
return result;
if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
goto fail;
__libc_missing_32bit_uids = 1;
}
# endif /* __NR_chown32 */
if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
|| ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
{
__set_errno (EINVAL);
return -1;
}
if (!__libc_old_chown && (flag & AT_SYMLINK_NOFOLLOW) == 0)
{
result = INTERNAL_SYSCALL (chown, err, 3, CHECK_STRING (file), owner,
group);
if (!INTERNAL_SYSCALL_ERROR_P (result, err))
return result;
if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
goto fail;
__libc_old_chown = 1;
}
result = INTERNAL_SYSCALL (lchown, err, 3, CHECK_STRING (file), owner,
group);
# elif __ASSUME_32BITUIDS
/* This implies __ASSUME_LCHOWN_SYSCALL. */
result = INTERNAL_SYSCALL (chown32, err, 3, CHECK_STRING (file), owner,
group);
# else
/* !__ASSUME_32BITUIDS && ASSUME_LCHOWN_SYSCALL */
# ifdef __NR_chown32
if (__libc_missing_32bit_uids <= 0)
{
result = INTERNAL_SYSCALL (chown32, err, 3, CHECK_STRING (file), owner,
group);
if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
return result;
if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
goto fail;
__libc_missing_32bit_uids = 1;
}
# endif /* __NR_chown32 */
if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
|| ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
{
__set_errno (EINVAL);
return -1;
}
result = INTERNAL_SYSCALL (chown, err, 3, CHECK_STRING (file), owner, group);
# endif
#else
result = INTERNAL_SYSCALL (chown, err, 3, CHECK_STRING (file), owner, group);
#endif
if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 0))
goto fail;
return result;
fail:
__atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
return -1;
}
|
