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
179
180
|
/*
* Copyright (C) 2015 John Crispin <blogic@openwrt.org>
* Copyright (C) 2015 Etienne Champetier <champetier.etienne@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation
*
* This program 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 General Public License for more details.
*/
#define _GNU_SOURCE
#include <assert.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <libubox/avl.h>
#include <libubox/avl-cmp.h>
#include "elf.h"
#include "fs.h"
#include "jail.h"
#include "log.h"
struct mount {
struct avl_node avl;
const char *path;
int readonly;
int error;
};
struct avl_tree mounts;
int add_mount(const char *path, int readonly, int error)
{
assert(path != NULL);
if (avl_find(&mounts, path))
return 1;
struct mount *m;
m = calloc(1, sizeof(struct mount));
assert(m != NULL);
m->avl.key = m->path = strdup(path);
m->readonly = readonly;
m->error = error;
avl_insert(&mounts, &m->avl);
DEBUG("adding mount %s ro(%d) err(%d)\n", m->path, m->readonly, m->error != 0);
return 0;
}
int mount_all(const char *jailroot) {
struct library *l;
struct mount *m;
avl_for_each_element(&libraries, l, avl)
add_mount(l->path, 1, -1);
avl_for_each_element(&mounts, m, avl)
if (mount_bind(jailroot, m->path, m->readonly, m->error))
return -1;
return 0;
}
void mount_list_init(void) {
avl_init(&mounts, avl_strcmp, false, NULL);
}
static int add_script_interp(const char *path, const char *map, int size)
{
int start = 2;
while (start < size && map[start] != '/') {
start++;
}
if (start >= size) {
ERROR("bad script interp (%s)", path);
return -1;
}
int stop = start + 1;
while (stop < size && map[stop] > 0x20 && map[stop] <= 0x7e) {
stop++;
}
if (stop >= size || (stop-start) > PATH_MAX) {
ERROR("bad script interp (%s)", path);
return -1;
}
char buf[PATH_MAX];
strncpy(buf, map+start, stop-start);
return add_path_and_deps(buf, 1, -1, 0);
}
int add_path_and_deps(const char *path, int readonly, int error, int lib)
{
assert(path != NULL);
if (lib == 0 && path[0] != '/') {
ERROR("%s is not an absolute path\n", path);
return error;
}
char *map = NULL;
int fd, ret = -1;
if (path[0] == '/') {
if (avl_find(&mounts, path))
return 0;
fd = open(path, O_RDONLY|O_CLOEXEC);
if (fd == -1)
return error;
add_mount(path, readonly, error);
} else {
if (avl_find(&libraries, path))
return 0;
char *fullpath;
fd = lib_open(&fullpath, path);
if (fd == -1)
return error;
if (fullpath) {
alloc_library(fullpath, path);
free(fullpath);
}
}
struct stat s;
if (fstat(fd, &s) == -1) {
ERROR("fstat(%s) failed: %s\n", path, strerror(errno));
ret = error;
goto out;
}
if (!S_ISREG(s.st_mode)) {
ret = 0;
goto out;
}
/* too small to be an ELF or a script -> "normal" file */
if (s.st_size < 4) {
ret = 0;
goto out;
}
map = mmap(NULL, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (map == MAP_FAILED) {
ERROR("failed to mmap %s\n", path);
ret = -1;
goto out;
}
if (map[0] == '#' && map[1] == '!') {
ret = add_script_interp(path, map, s.st_size);
goto out;
}
if (map[0] == ELFMAG0 && map[1] == ELFMAG1 && map[2] == ELFMAG2 && map[3] == ELFMAG3) {
ret = elf_load_deps(path, map);
goto out;
}
ret = 0;
out:
if (fd >= 0)
close(fd);
if (map)
munmap(map, s.st_size);
return ret;
}
|
