commit 4772f1da47bfdad8e0b3e3cdbf1bdc6bda0443b1
author Tom Cherry <tomcherry@google.com> Tue Jul 30 09:34:41 2019 -0700
committer Tom Cherry <tomcherry@google.com> Thu Aug 01 10:54:47 2019 -0700
tree 3f40d0bee7fa7394dc09ed9d73f2cd1d9f3d6932
parent c5cf85db23ac8c8a0206e911d73ef1c42ad66ed6

init: check the arguments of builtins during the build

Host init verifier already checks that the names and number of
arguments for builtins are correct, but it can check more.  This
change ensures that property expansions are well formed, and that
arguments that can be parsed on the host are correct.  For example it
checks that UIDs and GIDs exist, that numerical values can be parsed,
and that rlimit strings are correct.

Test: build

Change-Id: Ied8882498a88a9f8324db6b8d1020aeeccc8177b

init/builtins.cpp

diff --git a/init/builtins.cpp b/init/builtins.cpp
index b6e26a1..e75f5cb 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -201,26 +201,26 @@
 static Result<void> do_exec(const BuiltinArguments& args) {
     auto service = Service::MakeTemporaryOneshotService(args.args);
     if (!service) {
-        return Error() << "Could not create exec service";
+        return Error() << "Could not create exec service: " << service.error();
     }
-    if (auto result = service->ExecStart(); !result) {
+    if (auto result = (*service)->ExecStart(); !result) {
         return Error() << "Could not start exec service: " << result.error();
     }
 
-    ServiceList::GetInstance().AddService(std::move(service));
+    ServiceList::GetInstance().AddService(std::move(*service));
     return {};
 }
 
 static Result<void> do_exec_background(const BuiltinArguments& args) {
     auto service = Service::MakeTemporaryOneshotService(args.args);
     if (!service) {
-        return Error() << "Could not create exec background service";
+        return Error() << "Could not create exec background service: " << service.error();
     }
-    if (auto result = service->Start(); !result) {
+    if (auto result = (*service)->Start(); !result) {
         return Error() << "Could not start exec background service: " << result.error();
     }
 
-    ServiceList::GetInstance().AddService(std::move(service));
+    ServiceList::GetInstance().AddService(std::move(*service));
     return {};
 }
 
@@ -344,7 +344,7 @@
         if (args.size() == 5) {
             gid = DecodeUid(args[4]);
             if (!gid) {
-                return Error() << "Unable to decode GID for '" << args[3] << "': " << gid.error();
+                return Error() << "Unable to decode GID for '" << args[4] << "': " << gid.error();
             }
         }
 
@@ -936,40 +936,17 @@
 }
 
 static Result<void> do_restorecon(const BuiltinArguments& args) {
+    auto restorecon_info = ParseRestorecon(args.args);
+    if (!restorecon_info) {
+        return restorecon_info.error();
+    }
+
+    const auto& [flag, paths] = *restorecon_info;
+
     int ret = 0;
-
-    struct flag_type {const char* name; int value;};
-    static const flag_type flags[] = {
-        {"--recursive", SELINUX_ANDROID_RESTORECON_RECURSE},
-        {"--skip-ce", SELINUX_ANDROID_RESTORECON_SKIPCE},
-        {"--cross-filesystems", SELINUX_ANDROID_RESTORECON_CROSS_FILESYSTEMS},
-        {0, 0}
-    };
-
-    int flag = 0;
-
-    bool in_flags = true;
-    for (size_t i = 1; i < args.size(); ++i) {
-        if (android::base::StartsWith(args[i], "--")) {
-            if (!in_flags) {
-                return Error() << "flags must precede paths";
-            }
-            bool found = false;
-            for (size_t j = 0; flags[j].name; ++j) {
-                if (args[i] == flags[j].name) {
-                    flag |= flags[j].value;
-                    found = true;
-                    break;
-                }
-            }
-            if (!found) {
-                return Error() << "bad flag " << args[i];
-            }
-        } else {
-            in_flags = false;
-            if (selinux_android_restorecon(args[i].c_str(), flag) < 0) {
-                ret = errno;
-            }
+    for (const auto& path : paths) {
+        if (selinux_android_restorecon(path.c_str(), flag) < 0) {
+            ret = errno;
         }
     }
 
@@ -1056,9 +1033,9 @@
                                             const BuiltinArguments& args) {
     auto service = Service::MakeTemporaryOneshotService(args.args);
     if (!service) {
-        return Error() << "Could not create exec service";
+        return Error() << "Could not create exec service: " << service.error();
     }
-    service->AddReapCallback([reboot_reason](const siginfo_t& siginfo) {
+    (*service)->AddReapCallback([reboot_reason](const siginfo_t& siginfo) {
         if (siginfo.si_code != CLD_EXITED || siginfo.si_status != 0) {
             // TODO (b/122850122): support this in gsi
             if (fscrypt_is_native() && !android::gsi::IsGsiRunning()) {
@@ -1073,10 +1050,10 @@
             }
         }
     });
-    if (auto result = service->ExecStart(); !result) {
+    if (auto result = (*service)->ExecStart(); !result) {
         return Error() << "Could not start exec service: " << result.error();
     }
-    ServiceList::GetInstance().AddService(std::move(service));
+    ServiceList::GetInstance().AddService(std::move(*service));
     return {};
 }