/* * 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 #include #include #include #include #include #include #include #include #include #include #include #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 */ 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/*" }, /* CM's daemonized su doesn't need the setuid bit */ { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/su" }, /* the following five files are INTENTIONALLY set-uid, but they * are NOT included on user builds. */ { 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_SHELL, 0, "system/etc/init.d/*" }, { 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; }