diff options
| -rw-r--r-- | cmds/installd/InstalldNativeService.cpp | 78 |
1 files changed, 70 insertions, 8 deletions
diff --git a/cmds/installd/InstalldNativeService.cpp b/cmds/installd/InstalldNativeService.cpp index f7d73b08cb..509dd92b14 100644 --- a/cmds/installd/InstalldNativeService.cpp +++ b/cmds/installd/InstalldNativeService.cpp @@ -78,6 +78,7 @@ static constexpr const char* PKG_LIB_POSTFIX = "/lib"; static constexpr const char* CACHE_DIR_POSTFIX = "/cache"; static constexpr const char* CODE_CACHE_DIR_POSTFIX = "/code_cache"; +static constexpr const char *kIdMapPath = "/system/bin/idmap"; static constexpr const char* IDMAP_PREFIX = "/data/resource-cache/"; static constexpr const char* IDMAP_SUFFIX = "@idmap"; @@ -1941,14 +1942,58 @@ out: static void run_idmap(const char *target_apk, const char *overlay_apk, int idmap_fd) { - static const char *IDMAP_BIN = "/system/bin/idmap"; - static const size_t MAX_INT_LEN = 32; - char idmap_str[MAX_INT_LEN]; + execl(kIdMapPath, kIdMapPath, "--fd", target_apk, overlay_apk, + StringPrintf("%d", idmap_fd).c_str(), (char*)NULL); + PLOG(ERROR) << "execl (" << kIdMapPath << ") failed"; +} + +static void run_verify_idmap(const char *target_apk, const char *overlay_apk, int idmap_fd) +{ + execl(kIdMapPath, kIdMapPath, "--verify", target_apk, overlay_apk, + StringPrintf("%d", idmap_fd).c_str(), (char*)NULL); + PLOG(ERROR) << "execl (" << kIdMapPath << ") failed"; +} + +static bool delete_stale_idmap(const char* target_apk, const char* overlay_apk, + const char* idmap_path, int32_t uid) { + int idmap_fd = open(idmap_path, O_RDWR); + if (idmap_fd < 0) { + PLOG(ERROR) << "idmap open failed: " << idmap_path; + unlink(idmap_path); + return true; + } + + pid_t pid; + pid = fork(); + if (pid == 0) { + /* child -- drop privileges before continuing */ + if (setgid(uid) != 0) { + LOG(ERROR) << "setgid(" << uid << ") failed during idmap"; + exit(1); + } + if (setuid(uid) != 0) { + LOG(ERROR) << "setuid(" << uid << ") failed during idmap"; + exit(1); + } + if (flock(idmap_fd, LOCK_EX | LOCK_NB) != 0) { + PLOG(ERROR) << "flock(" << idmap_path << ") failed during idmap"; + exit(1); + } - snprintf(idmap_str, sizeof(idmap_str), "%d", idmap_fd); + run_verify_idmap(target_apk, overlay_apk, idmap_fd); + exit(1); /* only if exec call to deleting stale idmap failed */ + } else { + int status = wait_child(pid); + close(idmap_fd); - execl(IDMAP_BIN, IDMAP_BIN, "--fd", target_apk, overlay_apk, idmap_str, (char*)NULL); - ALOGE("execl(%s) failed: %s\n", IDMAP_BIN, strerror(errno)); + if (status != 0) { + // Failed on verifying if idmap is made from target_apk and overlay_apk. + LOG(DEBUG) << "delete stale idmap: " << idmap_path; + unlink(idmap_path); + return true; + } + } + return false; } // Transform string /a/b/c.apk to (prefix)/a@b@c.apk@(suffix) @@ -1997,6 +2042,8 @@ binder::Status InstalldNativeService::idmap(const std::string& targetApkPath, int idmap_fd = -1; char idmap_path[PATH_MAX]; + struct stat idmap_stat; + bool outdated = false; if (flatten_path(IDMAP_PREFIX, IDMAP_SUFFIX, overlay_apk, idmap_path, sizeof(idmap_path)) == -1) { @@ -2004,8 +2051,18 @@ binder::Status InstalldNativeService::idmap(const std::string& targetApkPath, goto fail; } - unlink(idmap_path); - idmap_fd = open(idmap_path, O_RDWR | O_CREAT | O_EXCL, 0644); + if (stat(idmap_path, &idmap_stat) < 0) { + outdated = true; + } else { + outdated = delete_stale_idmap(target_apk, overlay_apk, idmap_path, uid); + } + + if (outdated) { + idmap_fd = open(idmap_path, O_RDWR | O_CREAT | O_EXCL, 0644); + } else { + idmap_fd = open(idmap_path, O_RDWR); + } + if (idmap_fd < 0) { ALOGE("idmap cannot open '%s' for output: %s\n", idmap_path, strerror(errno)); goto fail; @@ -2019,6 +2076,11 @@ binder::Status InstalldNativeService::idmap(const std::string& targetApkPath, goto fail; } + if (!outdated) { + close(idmap_fd); + return ok(); + } + pid_t pid; pid = fork(); if (pid == 0) { |