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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // This is a list of environment variables which the ELF loader unsets when | 5 // This is a list of environment variables which the ELF loader unsets when |
6 // loading a SUID binary. Because they are unset rather than just ignored, they | 6 // loading a SUID binary. Because they are unset rather than just ignored, they |
7 // aren't passed to child processes of SUID processes either. | 7 // aren't passed to child processes of SUID processes either. |
8 // | 8 // |
9 // We need to save these environment variables before running a SUID sandbox | 9 // We need to save these environment variables before running a SUID sandbox |
10 // and restore them before running child processes (but after dropping root). | 10 // and restore them before running child processes (but after dropping root). |
11 // | 11 // |
12 // List gathered from glibc sources (00ebd7ed58df389a78e41dece058048725cb585e): | 12 // List gathered from glibc sources (00ebd7ed58df389a78e41dece058048725cb585e): |
13 // sysdeps/unix/sysv/linux/i386/dl-librecon.h | 13 // sysdeps/unix/sysv/linux/i386/dl-librecon.h |
14 // sysdeps/generic/unsecvars.h | 14 // sysdeps/generic/unsecvars.h |
15 | 15 |
16 #ifndef SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ | 16 #ifndef SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ |
17 #define SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ | 17 #define SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ |
18 | 18 |
19 #if defined(__cplusplus) | 19 #include <stdint.h> |
20 #include <limits> | |
21 #define SIZE_MAX std::numeric_limits<size_t>::max() | |
22 #endif | |
23 | |
24 #include <stdlib.h> // malloc | 20 #include <stdlib.h> // malloc |
25 #include <string.h> // memcpy | 21 #include <string.h> // memcpy |
26 | 22 |
27 static const char* kSUIDUnsafeEnvironmentVariables[] = { | 23 static const char* kSUIDUnsafeEnvironmentVariables[] = { |
28 "LD_AOUT_LIBRARY_PATH", | 24 "LD_AOUT_LIBRARY_PATH", |
29 "LD_AOUT_PRELOAD", | 25 "LD_AOUT_PRELOAD", |
30 "GCONV_PATH", | 26 "GCONV_PATH", |
31 "GETCONF_DIR", | 27 "GETCONF_DIR", |
32 "HOSTALIASES", | 28 "HOSTALIASES", |
33 "LD_AUDIT", | 29 "LD_AUDIT", |
(...skipping 15 matching lines...) Expand all Loading... |
49 "RES_OPTIONS", | 45 "RES_OPTIONS", |
50 "TMPDIR", | 46 "TMPDIR", |
51 "TZDIR", | 47 "TZDIR", |
52 NULL, | 48 NULL, |
53 }; | 49 }; |
54 | 50 |
55 // Return a malloc allocated string containing the 'saved' environment variable | 51 // Return a malloc allocated string containing the 'saved' environment variable |
56 // name for a given environment variable. | 52 // name for a given environment variable. |
57 static inline char* SandboxSavedEnvironmentVariable(const char* envvar) { | 53 static inline char* SandboxSavedEnvironmentVariable(const char* envvar) { |
58 const size_t envvar_len = strlen(envvar); | 54 const size_t envvar_len = strlen(envvar); |
| 55 const size_t kMaxSizeT = (size_t) -1; |
59 | 56 |
60 if (envvar_len > SIZE_MAX - 1 -8) | 57 if (envvar_len > kMaxSizeT - 1 -8) |
61 return NULL; | 58 return NULL; |
62 | 59 |
63 const size_t saved_envvarlen = envvar_len + 1 /* NUL terminator */ + | 60 const size_t saved_envvarlen = envvar_len + 1 /* NUL terminator */ + |
64 8 /* strlen("SANDBOX_") */; | 61 8 /* strlen("SANDBOX_") */; |
65 char* const saved_envvar = (char*) malloc(saved_envvarlen); | 62 char* const saved_envvar = (char*) malloc(saved_envvarlen); |
66 if (!saved_envvar) | 63 if (!saved_envvar) |
67 return NULL; | 64 return NULL; |
68 | 65 |
69 memcpy(saved_envvar, "SANDBOX_", 8); | 66 memcpy(saved_envvar, "SANDBOX_", 8); |
70 memcpy(saved_envvar + 8, envvar, envvar_len); | 67 memcpy(saved_envvar + 8, envvar, envvar_len); |
71 saved_envvar[8 + envvar_len] = 0; | 68 saved_envvar[8 + envvar_len] = 0; |
72 | 69 |
73 return saved_envvar; | 70 return saved_envvar; |
74 } | 71 } |
75 | 72 |
76 #if defined(__cplusplus) | |
77 #undef SIZE_MAX | |
78 #endif | |
79 | |
80 #endif // SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ | 73 #endif // SANDBOX_LINUX_SUID_SUID_UNSAFE_ENVIRONMENT_VARIABLES_H_ |
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