| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* This file is used to define the properties of the filesystem |
| ** images generated by build tools (mkbootfs and mkyaffs2image) and |
| ** by the device side of adb. |
| */ |
| |
| #define LOG_TAG "fs_config" |
| |
| #define _GNU_SOURCE |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| |
| #include <log/log.h> |
| #include <private/android_filesystem_config.h> |
| #include <utils/Compat.h> |
| |
| #ifndef O_BINARY |
| #define O_BINARY 0 |
| #endif |
| |
| /* The following structure is stored little endian */ |
| struct fs_path_config_from_file { |
| uint16_t len; |
| uint16_t mode; |
| uint16_t uid; |
| uint16_t gid; |
| uint64_t capabilities; |
| char prefix[]; |
| } __attribute__((__aligned__(sizeof(uint64_t)))); |
| |
| /* My kingdom for <endian.h> */ |
| static inline uint16_t get2LE(const uint8_t* src) |
| { |
| return src[0] | (src[1] << 8); |
| } |
| |
| static inline uint64_t get8LE(const uint8_t* src) |
| { |
| uint32_t low, high; |
| |
| low = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24); |
| high = src[4] | (src[5] << 8) | (src[6] << 16) | (src[7] << 24); |
| return ((uint64_t) high << 32) | (uint64_t) low; |
| } |
| |
| #define ALIGN(x, alignment) ( ((x) + ((alignment) - 1)) & ~((alignment) - 1) ) |
| |
| /* Rules for directories. |
| ** These rules are applied based on "first match", so they |
| ** should start with the most specific path and work their |
| ** way up to the root. |
| */ |
| |
| static const struct fs_path_config android_dirs[] = { |
| { 00770, AID_SYSTEM, AID_CACHE, 0, "cache" }, |
| { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" }, |
| { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" }, |
| { 00771, AID_ROOT, AID_ROOT, 0, "data/dalvik-cache" }, |
| { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/data" }, |
| { 00771, AID_SHELL, AID_SHELL, 0, "data/local/tmp" }, |
| { 00771, AID_SHELL, AID_SHELL, 0, "data/local" }, |
| { 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" }, |
| { 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" }, |
| { 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" }, |
| { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" }, |
| { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" }, |
| { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" }, |
| { 00750, AID_ROOT, AID_SHELL, 0, "sbin" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/bin" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin" }, |
| { 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "vendor" }, |
| { 00777, AID_ROOT, AID_ROOT, 0, "sdcard" }, |
| { 00755, AID_ROOT, AID_ROOT, 0, 0 }, |
| }; |
| |
| /* Rules for files. |
| ** These rules are applied based on "first match", so they |
| ** should start with the most specific path and work their |
| ** way up to the root. Prefixes ending in * denotes wildcard |
| ** and will allow partial matches. |
| */ |
| static const char conf_dir[] = "/system/etc/fs_config_dirs"; |
| static const char conf_file[] = "/system/etc/fs_config_files"; |
| |
| static const struct fs_path_config android_files[] = { |
| { 00440, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.rc" }, |
| { 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.sh" }, |
| { 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.ril" }, |
| { 00550, AID_DHCP, AID_SHELL, 0, "system/etc/dhcpcd/dhcpcd-run-hooks" }, |
| { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" }, |
| { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" }, |
| { 00444, AID_ROOT, AID_ROOT, 0, conf_dir + 1 }, |
| { 00444, AID_ROOT, AID_ROOT, 0, conf_file + 1 }, |
| { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" }, |
| { 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" }, |
| { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" }, |
| { 00644, AID_APP, AID_APP, 0, "data/data/*" }, |
| |
| /* the following five files are INTENTIONALLY set-uid, but they |
| * are NOT included on user builds. */ |
| { 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" }, |
| { 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/librank" }, |
| { 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procrank" }, |
| { 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" }, |
| { 04770, AID_ROOT, AID_RADIO, 0, "system/bin/pppd-ril" }, |
| |
| /* the following files have enhanced capabilities and ARE included in user builds. */ |
| { 00750, AID_ROOT, AID_SHELL, (1ULL << CAP_SETUID) | (1ULL << CAP_SETGID), "system/bin/run-as" }, |
| { 00700, AID_SYSTEM, AID_SHELL, (1ULL << CAP_BLOCK_SUSPEND), "system/bin/inputflinger" }, |
| |
| { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" }, |
| { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/install-recovery.sh" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/*" }, |
| { 00755, AID_ROOT, AID_ROOT, 0, "system/lib/valgrind/*" }, |
| { 00755, AID_ROOT, AID_ROOT, 0, "system/lib64/valgrind/*" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/bin/*" }, |
| { 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" }, |
| { 00750, AID_ROOT, AID_SHELL, 0, "sbin/*" }, |
| { 00755, AID_ROOT, AID_ROOT, 0, "bin/*" }, |
| { 00750, AID_ROOT, AID_SHELL, 0, "init*" }, |
| { 00750, AID_ROOT, AID_SHELL, 0, "sbin/fs_mgr" }, |
| { 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" }, |
| { 00644, AID_ROOT, AID_ROOT, 0, 0 }, |
| }; |
| |
| static int fs_config_open(int dir, const char *target_out_path) |
| { |
| int fd = -1; |
| |
| if (target_out_path && *target_out_path) { |
| /* target_out_path is the path to the directory holding content of system partition |
| but as we cannot guaranty it ends with '/system' we need this below skip_len logic */ |
| char *name = NULL; |
| int target_out_path_len = strlen(target_out_path); |
| int skip_len = strlen("/system"); |
| |
| if (target_out_path[target_out_path_len] == '/') { |
| skip_len++; |
| } |
| asprintf(&name, "%s%s", target_out_path, (dir ? conf_dir : conf_file) + skip_len); |
| if (name) { |
| fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY)); |
| free(name); |
| } |
| } |
| if (fd < 0) { |
| fd = TEMP_FAILURE_RETRY(open(dir ? conf_dir : conf_file, O_RDONLY | O_BINARY)); |
| } |
| return fd; |
| } |
| |
| static bool fs_config_cmp(bool dir, const char *prefix, size_t len, |
| const char *path, size_t plen) |
| { |
| if (dir) { |
| if (plen < len) { |
| return false; |
| } |
| } else { |
| /* If name ends in * then allow partial matches. */ |
| if (prefix[len - 1] == '*') { |
| return !strncmp(prefix, path, len - 1); |
| } |
| if (plen != len) { |
| return false; |
| } |
| } |
| return !strncmp(prefix, path, len); |
| } |
| |
| void fs_config(const char *path, int dir, const char *target_out_path, |
| unsigned *uid, unsigned *gid, unsigned *mode, uint64_t *capabilities) |
| { |
| const struct fs_path_config *pc; |
| int fd, plen; |
| |
| if (path[0] == '/') { |
| path++; |
| } |
| |
| plen = strlen(path); |
| |
| fd = fs_config_open(dir, target_out_path); |
| if (fd >= 0) { |
| struct fs_path_config_from_file header; |
| |
| while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) { |
| char *prefix; |
| uint16_t host_len = get2LE((const uint8_t *)&header.len); |
| ssize_t len, remainder = host_len - sizeof(header); |
| if (remainder <= 0) { |
| ALOGE("%s len is corrupted", dir ? conf_dir : conf_file); |
| break; |
| } |
| prefix = calloc(1, remainder); |
| if (!prefix) { |
| ALOGE("%s out of memory", dir ? conf_dir : conf_file); |
| break; |
| } |
| if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) { |
| free(prefix); |
| ALOGE("%s prefix is truncated", dir ? conf_dir : conf_file); |
| break; |
| } |
| len = strnlen(prefix, remainder); |
| if (len >= remainder) { /* missing a terminating null */ |
| free(prefix); |
| ALOGE("%s is corrupted", dir ? conf_dir : conf_file); |
| break; |
| } |
| if (fs_config_cmp(dir, prefix, len, path, plen)) { |
| free(prefix); |
| close(fd); |
| *uid = get2LE((const uint8_t *)&(header.uid)); |
| *gid = get2LE((const uint8_t *)&(header.gid)); |
| *mode = (*mode & (~07777)) | get2LE((const uint8_t *)&(header.mode)); |
| *capabilities = get8LE((const uint8_t *)&(header.capabilities)); |
| return; |
| } |
| free(prefix); |
| } |
| close(fd); |
| } |
| |
| pc = dir ? android_dirs : android_files; |
| for(; pc->prefix; pc++){ |
| if (fs_config_cmp(dir, pc->prefix, strlen(pc->prefix), path, plen)) { |
| break; |
| } |
| } |
| *uid = pc->uid; |
| *gid = pc->gid; |
| *mode = (*mode & (~07777)) | pc->mode; |
| *capabilities = pc->capabilities; |
| } |
| |
| ssize_t fs_config_generate(char *buffer, size_t length, const struct fs_path_config *pc) |
| { |
| struct fs_path_config_from_file *p = (struct fs_path_config_from_file *)buffer; |
| size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t)); |
| |
| if ((length < len) || (len > UINT16_MAX)) { |
| return -ENOSPC; |
| } |
| memset(p, 0, len); |
| uint16_t host_len = len; |
| p->len = get2LE((const uint8_t *)&host_len); |
| p->mode = get2LE((const uint8_t *)&(pc->mode)); |
| p->uid = get2LE((const uint8_t *)&(pc->uid)); |
| p->gid = get2LE((const uint8_t *)&(pc->gid)); |
| p->capabilities = get8LE((const uint8_t *)&(pc->capabilities)); |
| strcpy(p->prefix, pc->prefix); |
| return len; |
| } |
