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
|
/*
* Copyright (C) 2016 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "linker_namespaces.h"
#include "linker_globals.h"
#include "linker_soinfo.h"
#include "linker_utils.h"
#include <dlfcn.h>
// Given an absolute path, can this library be loaded into this namespace?
bool android_namespace_t::is_accessible(const std::string& file) {
if (!is_isolated_) {
return true;
}
if (!allowed_libs_.empty()) {
const char *lib_name = basename(file.c_str());
if (std::find(allowed_libs_.begin(), allowed_libs_.end(), lib_name) == allowed_libs_.end()) {
return false;
}
}
for (const auto& dir : ld_library_paths_) {
if (file_is_in_dir(file, dir)) {
return true;
}
}
for (const auto& dir : default_library_paths_) {
if (file_is_in_dir(file, dir)) {
return true;
}
}
for (const auto& dir : permitted_paths_) {
if (file_is_under_dir(file, dir)) {
return true;
}
}
return false;
}
// Are symbols from this shared object accessible for symbol lookups in a library from this
// namespace?
bool android_namespace_t::is_accessible(soinfo* s) {
auto is_accessible_ftor = [this] (soinfo* si, bool allow_secondary) {
// This is workaround for apps hacking into soinfo list.
// and inserting their own entries into it. (http://b/37191433)
if (!si->has_min_version(3)) {
DL_WARN("Warning: invalid soinfo version for \"%s\" (assuming inaccessible)",
si->get_soname());
return false;
}
if (si->get_primary_namespace() == this) {
return true;
}
// When we're looking up symbols, we want to search libraries from the same namespace (whether
// the namespace membership is primary or secondary), but we also want to search the immediate
// dependencies of libraries in our namespace. (e.g. Supposing that libapp.so -> libandroid.so
// crosses a namespace boundary, we want to search libandroid.so but not any of libandroid.so's
// dependencies).
//
// Some libraries may be present in this namespace via the secondary namespace list:
// - the executable
// - LD_PRELOAD and DF_1_GLOBAL libraries
// - libraries inherited during dynamic namespace creation (e.g. because of
// RTLD_GLOBAL / DF_1_GLOBAL / ANDROID_NAMESPACE_TYPE_SHARED)
//
// When a library's membership is secondary, we want to search its symbols, but not the symbols
// of its dependencies. The executable may depend on internal system libraries which should not
// be searched.
if (allow_secondary) {
const android_namespace_list_t& secondary_namespaces = si->get_secondary_namespaces();
if (secondary_namespaces.find(this) != secondary_namespaces.end()) {
return true;
}
}
return false;
};
if (is_accessible_ftor(s, true)) {
return true;
}
return !s->get_parents().visit([&](soinfo* si) {
return !is_accessible_ftor(si, false);
});
}
// TODO: this is slightly unusual way to construct
// the global group for relocation. Not every RTLD_GLOBAL
// library is included in this group for backwards-compatibility
// reasons.
//
// This group consists of the main executable, LD_PRELOADs
// and libraries with the DF_1_GLOBAL flag set.
soinfo_list_t android_namespace_t::get_global_group() {
soinfo_list_t global_group;
soinfo_list().for_each([&](soinfo* si) {
if ((si->get_dt_flags_1() & DF_1_GLOBAL) != 0) {
global_group.push_back(si);
}
});
return global_group;
}
// This function provides a list of libraries to be shared
// by the namespace. For the default namespace this is the global
// group (see get_global_group). For all others this is a group
// of RTLD_GLOBAL libraries (which includes the global group from
// the default namespace).
soinfo_list_t android_namespace_t::get_shared_group() {
if (this == &g_default_namespace) {
return get_global_group();
}
soinfo_list_t shared_group;
soinfo_list().for_each([&](soinfo* si) {
if ((si->get_rtld_flags() & RTLD_GLOBAL) != 0) {
shared_group.push_back(si);
}
});
return shared_group;
}
|
