ios: Build four more Mach message and exception utilities

This enables the following code in util/mach on iOS:
 - exception_behaviors.{cc,h}
 - exception_ports.{cc,h}
 - mach_message.{cc,h}
 - mach_message_server.{cc,h}

Only the ExceptionBehaviors and MachMessage tests are built, because the
other two are tested by multiprocess tests that won’t run on iOS.

The AuditPIDFromMachMessageTrailer function from mach_message.h is
excluded on iOS because it relies on <bsm/libbsm.h>, which is broken on
iOS: it depends on <bsm/audit_record.h>, which is missing from the SDK.
Additionally, the BSM function that Crashpad uses, audit_token_to_au32,
is marked as unavailable on iOS. Crashpad uses it on macOS to
authenticate Mach messages sent by other processes, but this is moot on
iOS.

Bug: crashpad:31
Change-Id: I5ebc4b80543989b9cd0b85b82eb4b3ff98c44e6c
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2155086
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>

util/BUILD.gn

@@ -254,8 +254,16 @@ static_library("util") {
     sources += [
       "mac/xattr.cc",
       "mac/xattr.h",
+      "mach/exception_behaviors.cc",
+      "mach/exception_behaviors.h",
+      "mach/exception_ports.cc",
+      "mach/exception_ports.h",
       "mach/mach_extensions.cc",
       "mach/mach_extensions.h",
+      "mach/mach_message.cc",
+      "mach/mach_message.h",
+      "mach/mach_message_server.cc",
+      "mach/mach_message_server.h",
       "misc/clock_mac.cc",
       "misc/paths_mac.cc",
       "synchronization/semaphore_mac.cc",
@@ -284,16 +292,8 @@ static_library("util") {
       "mach/exc_client_variants.h",
       "mach/exc_server_variants.cc",
       "mach/exc_server_variants.h",
-      "mach/exception_behaviors.cc",
-      "mach/exception_behaviors.h",
-      "mach/exception_ports.cc",
-      "mach/exception_ports.h",
       "mach/exception_types.cc",
       "mach/exception_types.h",
-      "mach/mach_message.cc",
-      "mach/mach_message.h",
-      "mach/mach_message_server.cc",
-      "mach/mach_message_server.h",
       "mach/notify_server.cc",
       "mach/notify_server.h",
       "mach/scoped_task_suspend.cc",
@@ -518,9 +518,7 @@ static_library("util") {
 
   if (crashpad_is_mac || crashpad_is_ios) {
     include_dirs += [ "$root_build_dir/gen" ]
-    deps += [
+    deps += [ ":mig_output" ]
-      ":mig_output",
-    ]
   }
 
   if (crashpad_is_mac) {
@@ -530,9 +528,7 @@ static_library("util") {
       "Foundation.framework",
       "IOKit.framework",
     ]
-    deps += [
+    deps += [ "../third_party/apple_cf:apple_cf" ]
-      "../third_party/apple_cf:apple_cf",
-    ]
   }
 
   if (crashpad_is_win) {
@@ -674,7 +670,9 @@ source_set("util_test") {
   if (crashpad_is_mac || crashpad_is_ios) {
     sources += [
       "mac/xattr_test.cc",
+      "mach/exception_behaviors_test.cc",
       "mach/mach_extensions_test.cc",
+      "mach/mach_message_test.cc",
     ]
   }
 
@@ -689,11 +687,9 @@ source_set("util_test") {
       "mach/composite_mach_message_server_test.cc",
       "mach/exc_client_variants_test.cc",
       "mach/exc_server_variants_test.cc",
-      "mach/exception_behaviors_test.cc",
       "mach/exception_ports_test.cc",
       "mach/exception_types_test.cc",
       "mach/mach_message_server_test.cc",
-      "mach/mach_message_test.cc",
       "mach/notify_server_test.cc",
       "mach/scoped_task_suspend_test.cc",
       "mach/symbolic_constants_mach_test.cc",

util/mach/mach_message.cc

@@ -15,7 +15,6 @@
 #include "util/mach/mach_message.h"
 
 #include <AvailabilityMacros.h>
-#include <bsm/libbsm.h>
 
 #include <limits>
 
@@ -24,6 +23,10 @@
 #include "util/misc/clock.h"
 #include "util/misc/implicit_cast.h"
 
+#if !defined(OS_IOS)
+#include <bsm/libbsm.h>
+#endif  // !OS_IOS
+
 namespace crashpad {
 
 namespace {
@@ -217,38 +220,6 @@ const mach_msg_trailer_t* MachMessageTrailerFromHeader(
   return reinterpret_cast<const mach_msg_trailer_t*>(trailer_address);
 }
 
-pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer) {
-  if (trailer->msgh_trailer_type != MACH_MSG_TRAILER_FORMAT_0) {
-    LOG(ERROR) << "unexpected msgh_trailer_type " << trailer->msgh_trailer_type;
-    return -1;
-  }
-  if (trailer->msgh_trailer_size <
-      REQUESTED_TRAILER_SIZE(kMachMessageReceiveAuditTrailer)) {
-    LOG(ERROR) << "small msgh_trailer_size " << trailer->msgh_trailer_size;
-    return -1;
-  }
-
-  const mach_msg_audit_trailer_t* audit_trailer =
-      reinterpret_cast<const mach_msg_audit_trailer_t*>(trailer);
-
-#if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_8
-  pid_t audit_pid;
-  audit_token_to_au32(audit_trailer->msgh_audit,
-                      nullptr,
-                      nullptr,
-                      nullptr,
-                      nullptr,
-                      nullptr,
-                      &audit_pid,
-                      nullptr,
-                      nullptr);
-#else
-  pid_t audit_pid = audit_token_to_pid(audit_trailer->msgh_audit);
-#endif
-
-  return audit_pid;
-}
-
 bool MachMessageDestroyReceivedPort(mach_port_t port,
                                     mach_msg_type_name_t port_right_type) {
   // This implements a subset of 10.10.5
@@ -282,4 +253,40 @@ bool MachMessageDestroyReceivedPort(mach_port_t port,
   }
 }
 
+#if !defined(OS_IOS)
+
+pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer) {
+  if (trailer->msgh_trailer_type != MACH_MSG_TRAILER_FORMAT_0) {
+    LOG(ERROR) << "unexpected msgh_trailer_type " << trailer->msgh_trailer_type;
+    return -1;
+  }
+  if (trailer->msgh_trailer_size <
+      REQUESTED_TRAILER_SIZE(kMachMessageReceiveAuditTrailer)) {
+    LOG(ERROR) << "small msgh_trailer_size " << trailer->msgh_trailer_size;
+    return -1;
+  }
+
+  const mach_msg_audit_trailer_t* audit_trailer =
+      reinterpret_cast<const mach_msg_audit_trailer_t*>(trailer);
+
+#if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_8
+  pid_t audit_pid;
+  audit_token_to_au32(audit_trailer->msgh_audit,
+                      nullptr,
+                      nullptr,
+                      nullptr,
+                      nullptr,
+                      nullptr,
+                      &audit_pid,
+                      nullptr,
+                      nullptr);
+#else
+  pid_t audit_pid = audit_token_to_pid(audit_trailer->msgh_audit);
+#endif
+
+  return audit_pid;
+}
+
+#endif  // !OS_IOS
+
 }  // namespace crashpad

util/mach/mach_message.h

@@ -19,6 +19,8 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include "build/build_config.h"
+
 namespace crashpad {
 
 //! \brief A Mach message option specifying that an audit trailer should be
@@ -166,6 +168,23 @@ void SetMIGReplyError(mach_msg_header_t* out_header, kern_return_t error);
 const mach_msg_trailer_t* MachMessageTrailerFromHeader(
     const mach_msg_header_t* header);
 
+//! \brief Destroys or deallocates a Mach port received in a Mach message.
+//!
+//! This function disposes of port rights received in a Mach message. Receive
+//! rights will be destroyed with `mach_port_mod_refs()`. Send and send-once
+//! rights will be deallocated with `mach_port_deallocate()`.
+//!
+//! \param[in] port The port to destroy or deallocate.
+//! \param[in] port_right_type The right type held for \a port:
+//!     `MACH_MSG_TYPE_PORT_RECEIVE`, `MACH_MSG_TYPE_PORT_SEND`, or
+//!     `MACH_MSG_TYPE_PORT_SEND_ONCE`.
+//!
+//! \return `true` on success, or `false` on failure with a message logged.
+bool MachMessageDestroyReceivedPort(mach_port_t port,
+                                    mach_msg_type_name_t port_right_type);
+
+#if !defined(OS_IOS) || DOXYGEN
+
 //! \brief Returns the process ID of a Mach message’s sender from its audit
 //!     trailer.
 //!
@@ -182,20 +201,7 @@ const mach_msg_trailer_t* MachMessageTrailerFromHeader(
 //!     audit information.
 pid_t AuditPIDFromMachMessageTrailer(const mach_msg_trailer_t* trailer);
 
-//! \brief Destroys or deallocates a Mach port received in a Mach message.
+#endif  // !OS_IOS
-//!
-//! This function disposes of port rights received in a Mach message. Receive
-//! rights will be destroyed with `mach_port_mod_refs()`. Send and send-once
-//! rights will be deallocated with `mach_port_deallocate()`.
-//!
-//! \param[in] port The port to destroy or deallocate.
-//! \param[in] port_right_type The right type held for \a port:
-//!     `MACH_MSG_TYPE_PORT_RECEIVE`, `MACH_MSG_TYPE_PORT_SEND`, or
-//!     `MACH_MSG_TYPE_PORT_SEND_ONCE`.
-//!
-//! \return `true` on success, or `false` on failure with a message logged.
-bool MachMessageDestroyReceivedPort(mach_port_t port,
-                                    mach_msg_type_name_t port_right_type);
 
 }  // namespace crashpad
 

util/mach/mach_message_test.cc

@@ -109,46 +109,6 @@ TEST(MachMessage, MachMessageTrailerFromHeader) {
   EXPECT_EQ(MachMessageTrailerFromHeader(&test.receive), &test.receive.trailer);
 }
 
-TEST(MachMessage, AuditPIDFromMachMessageTrailer) {
-  base::mac::ScopedMachReceiveRight port(NewMachPort(MACH_PORT_RIGHT_RECEIVE));
-  ASSERT_NE(port, kMachPortNull);
-
-  mach_msg_empty_send_t send = {};
-  send.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND_ONCE, 0);
-  send.header.msgh_size = sizeof(send);
-  send.header.msgh_remote_port = port.get();
-  mach_msg_return_t mr =
-      MachMessageWithDeadline(&send.header,
-                              MACH_SEND_MSG,
-                              0,
-                              MACH_PORT_NULL,
-                              kMachMessageDeadlineNonblocking,
-                              MACH_PORT_NULL,
-                              false);
-  ASSERT_EQ(mr, MACH_MSG_SUCCESS)
-      << MachErrorMessage(mr, "MachMessageWithDeadline send");
-
-  struct EmptyReceiveMessageWithAuditTrailer : public mach_msg_empty_send_t {
-    union {
-      mach_msg_trailer_t trailer;
-      mach_msg_audit_trailer_t audit_trailer;
-    };
-  };
-
-  EmptyReceiveMessageWithAuditTrailer receive;
-  mr = MachMessageWithDeadline(&receive.header,
-                               MACH_RCV_MSG | kMachMessageReceiveAuditTrailer,
-                               sizeof(receive),
-                               port.get(),
-                               kMachMessageDeadlineNonblocking,
-                               MACH_PORT_NULL,
-                               false);
-  ASSERT_EQ(mr, MACH_MSG_SUCCESS)
-      << MachErrorMessage(mr, "MachMessageWithDeadline receive");
-
-  EXPECT_EQ(AuditPIDFromMachMessageTrailer(&receive.trailer), getpid());
-}
-
 TEST(MachMessage, MachMessageDestroyReceivedPort) {
   mach_port_t port = NewMachPort(MACH_PORT_RIGHT_RECEIVE);
   ASSERT_NE(port, kMachPortNull);
@@ -198,6 +158,50 @@ TEST(MachMessage, MachMessageDestroyReceivedPort) {
   EXPECT_TRUE(MachMessageDestroyReceivedPort(port, MACH_MSG_TYPE_PORT_SEND));
 }
 
+#if !defined(OS_IOS)
+
+TEST(MachMessage, AuditPIDFromMachMessageTrailer) {
+  base::mac::ScopedMachReceiveRight port(NewMachPort(MACH_PORT_RIGHT_RECEIVE));
+  ASSERT_NE(port, kMachPortNull);
+
+  mach_msg_empty_send_t send = {};
+  send.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND_ONCE, 0);
+  send.header.msgh_size = sizeof(send);
+  send.header.msgh_remote_port = port.get();
+  mach_msg_return_t mr =
+      MachMessageWithDeadline(&send.header,
+                              MACH_SEND_MSG,
+                              0,
+                              MACH_PORT_NULL,
+                              kMachMessageDeadlineNonblocking,
+                              MACH_PORT_NULL,
+                              false);
+  ASSERT_EQ(mr, MACH_MSG_SUCCESS)
+      << MachErrorMessage(mr, "MachMessageWithDeadline send");
+
+  struct EmptyReceiveMessageWithAuditTrailer : public mach_msg_empty_send_t {
+    union {
+      mach_msg_trailer_t trailer;
+      mach_msg_audit_trailer_t audit_trailer;
+    };
+  };
+
+  EmptyReceiveMessageWithAuditTrailer receive;
+  mr = MachMessageWithDeadline(&receive.header,
+                               MACH_RCV_MSG | kMachMessageReceiveAuditTrailer,
+                               sizeof(receive),
+                               port.get(),
+                               kMachMessageDeadlineNonblocking,
+                               MACH_PORT_NULL,
+                               false);
+  ASSERT_EQ(mr, MACH_MSG_SUCCESS)
+      << MachErrorMessage(mr, "MachMessageWithDeadline receive");
+
+  EXPECT_EQ(AuditPIDFromMachMessageTrailer(&receive.trailer), getpid());
+}
+
+#endif  // !OS_IOS
+
 }  // namespace
 }  // namespace test
 }  // namespace crashpad