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/*
* Copyright (C) 2020 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.
*/
// b/170214442: Intercept bind calls on NETLINK_ROUTE sockets and getifaddrs() calls.
// This entire file will be reverted before release.
#include <async_safe/log.h>
#include <cutils/misc.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include "bionic_appcompat.h"
bool should_apply_soft_mac_restrictions(const char* const allowlist[]) {
if (getuid() < FIRST_APPLICATION_UID) {
// System app. No restrictions should be applied.
return false;
}
if (android_get_application_target_sdk_version() >= __ANDROID_API_R__) {
// Restrictions already applied by SELinux. Behave as normally.
return false;
}
char package_name[MAX_PACKAGE_NAME_LENGTH + 1];
if (get_package_name(package_name, sizeof(package_name)) < 0) {
// Error in getting own package name. Apply restrictions by default.
async_safe_format_log(ANDROID_LOG_ERROR, "mac-restrictions",
"Could not determine own package name for uid %d", getuid());
return true;
}
for (int i = 0; allowlist[i] != nullptr; i++) {
if (strcmp(package_name, allowlist[i]) == 0) {
async_safe_format_log(ANDROID_LOG_WARN, "mac-restrictions",
"Temporarily allowing %s to bypass MAC address restrictions.",
package_name);
return false;
}
}
return true;
}
bool should_apply_soft_mac_bind_restrictions() {
return should_apply_soft_mac_restrictions(soft_mac_bind_allowlist);
}
bool should_apply_soft_mac_getlink_restrictions() {
return should_apply_soft_mac_restrictions(soft_mac_getlink_allowlist);
}
int get_package_name(char* buffer, const int bufferlen) {
int file = open("/proc/self/cmdline", O_RDONLY | O_CLOEXEC);
if (file < 0) {
return file;
}
ssize_t len = read(file, buffer, bufferlen - 1);
if (len < 0) {
close(file);
return -1;
}
buffer[len] = 0;
close(file);
return 0;
}
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