source: trunk/base/src/darwintracelib1.0/darwintrace.h @ 114131

Last change on this file since 114131 was 114131, checked in by cal@…, 7 years ago

darwintrace: Don't always follow symlinks

Only follow symlinks in darwintrace_is_in_sandbox() when the DT_FOLLOWSYMS
flag is set. This has the following advantages:

  • lstat(2) and readlink(2) work on symlinks that point to files outside of the sandbox (previously, these attempts would have returned ENOENT).
  • readdir(3) is a lot faster again, because it doesn't have to lstat(2) and possibly readlink(2) every file in a loop.
  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Rev URL
File size: 6.3 KB
Line 
1/*
2 * Copyright (c) 2005 Apple Inc. All rights reserved.
3 * Copyright (c) 2005-2006 Paul Guyot <pguyot@kallisys.net>,
4 * All rights reserved.
5 * Copyright (c) 2006-2013 The MacPorts Project
6 *
7 * $Id: darwintrace.h 114131 2013-11-30 00:05:22Z cal@macports.org $
8 *
9 * @APPLE_BSD_LICENSE_HEADER_START@
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 *
15 * 1.  Redistributions of source code must retain the above copyright
16 *     notice, this list of conditions and the following disclaimer.
17 * 2.  Redistributions in binary form must reproduce the above copyright
18 *     notice, this list of conditions and the following disclaimer in the
19 *     documentation and/or other materials provided with the distribution.
20 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
21 *     its contributors may be used to endorse or promote products derived
22 *     from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
25 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
28 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 *
35 * @APPLE_BSD_LICENSE_HEADER_END@
36 */
37
38#ifdef HAVE_CONFIG_H
39#include <config.h>
40#endif
41
42#include <pthread.h>
43#include <stdbool.h>
44#include <stdio.h>
45
46/**
47 * DARWINTRACE_DEBUG: verbose output of operations to debug darwintrace
48 */
49#ifndef DARWINTRACE_DEBUG
50#define DARWINTRACE_DEBUG (0)
51#endif
52
53/**
54 * \c debug_printf() is a macro that will print a message prefixed with
55 * "darwintrace" and the calling process' PID to stderr, or to the file
56 * indicated by the environment variable \c DARWINTRACE_DEBUG, if set.
57 */
58#if DARWINTRACE_DEBUG
59#       define debug_printf(format, ...) \
60                if (__darwintrace_stderr != NULL) { \
61                        fprintf(__darwintrace_stderr, "darwintrace[%d:%p]: " format, getpid(), (void *) pthread_self(), __VA_ARGS__); \
62                        fflush(__darwintrace_stderr); \
63                }
64#else
65#   define debug_printf(...)
66#endif
67
68enum {
69        DT_REPORT     = 1 << 0,
70        DT_ALLOWDIR   = 1 << 1,
71        DT_FOLLOWSYMS = 1 << 2
72};
73
74/**
75 * Debug socket. Will be set by a constructor function in darwintrace.c.
76 */
77extern FILE *__darwintrace_stderr;
78
79/**
80 * Initializer function, ensures darwintrace has been properly set up and check
81 * whether this process was fork(2)'d or clone(2)'d since the last call. Call
82 * this before calling any other functions from this library.
83 */
84void __darwintrace_setup();
85
86/**
87 * Close the darwintrace socket and set it to \c NULL. Since this uses \c
88 * fclose(3), which internally calls \c close(2), which is intercepted by this
89 * library and this library prevents closing the socket to MacPorts, we use \c
90 * __darwintrace_close_sock to allow closing specific FDs.
91 */
92void __darwintrace_close();
93
94/**
95 * Check a path against the current sandbox
96 *
97 * \param[in] path the path to be checked; not necessarily absolute
98 * \param[in] flags A binary or combination of the following flags:
99 *                  - DT_REPORT: If access to this path is being denied, report
100 *                    it as sandbox violation. Set this for all operations that
101 *                    read file contents or check file attributes. Omit this
102 *                    flag for operations that might only attempt to access
103 *                    a file by chance, such as readdir(3).
104 *                  - DT_ALLOWDIR: Whether to always allow access if the given
105 *                    path references an existing directory. Set this for
106 *                    read operations such as stat(2), omit this for operations
107 *                    that modify directories like rmdir(2) and mkdir(2).
108 *                  - DT_FOLLOWSYMS: Check for and expand symlinks, while
109 *                    checking both the link name and the link target against
110 *                    the sandbox. Set this for all operations that read file
111 *                    contents or check file attributes. Omit this flag for
112 *                    operations that only list the file (or rather symlink)
113 *                    name.
114 * \return \c true if the file is within sandbox bounds, \c false if access
115 *         should be denied
116 */
117bool __darwintrace_is_in_sandbox(const char *path, int flags);
118
119#ifdef DARWINTRACE_USE_PRIVATE_API
120#include <errno.h>
121#include <stdlib.h>
122
123/**
124 * PID of the process darwintrace was last used in. This is used to detect
125 * forking and opening a new connection to the control socket in the child
126 * process. Not doing so would potentially cause two processes writing to the
127 * same socket.
128 */
129extern pid_t __darwintrace_pid;
130
131/**
132 * Copy of the DARWINTRACE_LOG environment variable to restore it in execve(2).
133 * Contains the path to the unix socket used for communication with the
134 * MacPorts-side of the sandbox.
135 */
136extern char *__env_darwintrace_log;
137
138/**
139 * Helper variable containing the number of the darwintrace socket, iff the
140 * close(2) syscall should be allowed to close it. Used by \c
141 * __darwintrace_close.
142 */
143extern volatile int __darwintrace_close_sock;
144
145/**
146 * pthread_key_t for the darwintrace socket to ensure the socket is only used
147 * from a single thread.
148 */
149extern pthread_key_t sock_key;
150
151/**
152 * Convenience getter function for the thread-local darwintrace socket. Do not
153 * consider this part of public API. It is only needed to prevent closing and
154 * duplicating over darwintrace's socket FDs.
155 */
156static inline FILE *__darwintrace_sock() {
157        return (FILE *) pthread_getspecific(sock_key);
158}
159
160/**
161 * Convenience setter function for the thread-local darwintrace socket. Do not
162 * consider this part of public API. It is only needed to prevent closing and
163 * duplicating over darwintrace's socket FDs.
164 */
165static inline void __darwintrace_sock_set(FILE *stream) {
166        if (0 != (errno = pthread_setspecific(sock_key, stream))) {
167                perror("darwintrace: pthread_setspecific");
168                abort();
169        }
170}
171#endif /* defined(DARWINTRACE_USE_PRIVATE_API) */
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