linker/linker_note_gnu_property_test.cpp - platform/bionic - Git at Google

 /*
  * Copyright (C) 2020 The Android Open Source Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 #include <stdlib.h>
 #include <iostream>
 #include <sstream>
 #include <string>

 #include <gtest/gtest.h>

 #include "linker.h"
 #include "linker_globals.h"
 #include "linker_note_gnu_property.h"
 #include "platform/bionic/macros.h"

 #define SONAME "test_so"

 static char error_buffer[1024];

 char* linker_get_error_buffer() {
   return error_buffer;
 }

 size_t linker_get_error_buffer_size() {
   return std::size(error_buffer);
 }

 static void reset_error_buffer() {
   error_buffer[0] = '\0';
 }

 platform_properties g_platform_properties {
 #if defined(__aarch64__)
   // Assume "hardware" supports Armv8.5-A BTI.
   .bti_supported = true
 #endif
 };

 // Helper macro to make the test cleaner.
 #define PHDR_WITH_NOTE_GNU_PROPERTY(__prop)                                   \
   reset_error_buffer();                                                       \
   ElfW(Phdr) phdrs[] = {                                                      \
       {.p_type = PT_LOAD},                                                    \
       {                                                                       \
           .p_type = PT_GNU_PROPERTY,                                          \
           .p_vaddr = reinterpret_cast<ElfW(Addr)>(__prop),                    \
           .p_memsz = sizeof(ElfW(NhdrGNUProperty)) + (__prop)->nhdr.n_descsz, \
       },                                                                      \
       {.p_type = PT_NULL},                                                    \
   };                                                                          \
   auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME)

 // Helper to check for no error message.
 #define ASSERT_NO_ERROR_MSG() ASSERT_STREQ(error_buffer, "")

 // Helper to check expected error message.
 #define ASSERT_ERROR_MSG_EQ(__expected) ASSERT_STREQ(error_buffer, "\"" SONAME "\" " __expected)

 static void test_bti_not_supported(GnuPropertySection& note __unused) {
 #if defined(__aarch64__)
   ASSERT_FALSE(note.IsBTICompatible());
 #endif
 }

 #if defined(__aarch64__)
 static void test_bti_supported(GnuPropertySection& note __unused) {
   ASSERT_TRUE(note.IsBTICompatible());
 }
 #endif

 // Helper class to build a well-formed .note.gnu.property section.
 class GnuPropertySectionBuilder {
  public:
   GnuPropertySectionBuilder() {
     note = reinterpret_cast<ElfW(NhdrGNUProperty)*>(&section[0]);
     note->nhdr.n_namesz = 4;
     note->nhdr.n_descsz = 0;
     note->nhdr.n_type = NT_GNU_PROPERTY_TYPE_0;
     memcpy(note->n_name, "GNU", 4);
   }

   template <typename T>
   bool push(ElfW(Word) pr_type, ElfW(Word) pr_datasz, const T* pr_data) {
     // Must be aligned.
     const uintptr_t addition = align_up(pr_datasz, sizeof(ElfW(Addr)));
     if ((offset() + addition) > kMaxSectionSize) {
       return false;
     }
     ++entries;
     ElfW(Prop)* prop = reinterpret_cast<ElfW(Prop)*>(&section[offset()]);
     // Header
     prop->pr_type = pr_type;
     prop->pr_datasz = pr_datasz;
     step(2 * sizeof(ElfW(Word)));
     // Data
     memcpy(&section[offset()], reinterpret_cast<const void*>(pr_data), pr_datasz);
     step(pr_datasz);
     // Padding
     memset(&section[offset()], 0xAA, addition - pr_datasz);
     step(addition - pr_datasz);
     return true;
   }

   ElfW(NhdrGNUProperty)* data() const { return note; }

   void dump() const {
     std::cout << ".note.gnu.property\n";
     dump_member("n_namesz", note->nhdr.n_namesz);
     dump_member("n_descsz", note->nhdr.n_descsz);
     dump_member("n_type  ", note->nhdr.n_type);
     dump_member("n_name  ", note->n_name);
     dump_member("entries ", entries);
     if (entries > 0) {
       std::cout << "    raw data:";
       const uintptr_t offset = note->nhdr.n_descsz + 16;
       for (uintptr_t offs = 16; offs < offset; ++offs) {
         std::cout << std::hex;
         if ((offs % 8) == 0) {
           std::cout << "\n   ";
         }
         auto value = static_cast<unsigned>(section[offs]);
         std::cout << " ";
         if (value < 0x10) {
           std::cout << "0";
         }
         std::cout << static_cast<unsigned>(section[offs]);
       }
       std::cout << std::dec << "\n";
     }
   }

   void corrupt_n_descsz(ElfW(Word) n_descsz) { note->nhdr.n_descsz = n_descsz; }

  private:
   template <typename T>
   void dump_member(const char* name, T value) const {
     std::cout << "  " << name << " " << value << "\n";
   }

   ElfW(Word) offset() const { return note->nhdr.n_descsz + 16; }

   template <typename T>
   void step(T value) {
     note->nhdr.n_descsz += static_cast<ElfW(Word)>(value);
   }

   static const size_t kMaxSectionSize = 1024;

   alignas(8) uint8_t section[kMaxSectionSize];
   ElfW(NhdrGNUProperty)* note;
   size_t entries = 0;
 };

 // Tests that the default constructed instance does not report support
 // for Armv8.5-A BTI.
 TEST(note_gnu_property, default) {
   GnuPropertySection note;
   test_bti_not_supported(note);
   ASSERT_NO_ERROR_MSG();
 }

 // Tests that an instance without valid phdr pointer does not report
 // support for Armv8.5-A BTI.
 TEST(note_gnu_property, phdr_null) {
   auto note = GnuPropertySection(nullptr, 0, 0, SONAME);
   test_bti_not_supported(note);
   ASSERT_NO_ERROR_MSG();
 }

 // Tests that an instance without finding PT_GNU_PROPERTY does not
 // report support for Armv8.5-A BTI.
 TEST(note_gnu_property, no_pt_gnu_property) {
   ElfW(Phdr) phdrs[] = {
       {.p_type = PT_LOAD},
       {.p_type = PT_NULL},
   };

   reset_error_buffer();
   auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
   test_bti_not_supported(note);
   ASSERT_NO_ERROR_MSG();
 }

 // Tests the validity check for invalid PT_GNU_PROPERTY size.
 TEST(note_gnu_property, pt_gnu_property_bad_size) {
   ElfW(Phdr) phdrs[] = {
       {.p_type = PT_LOAD},
       {
           .p_type = PT_GNU_PROPERTY,
           .p_vaddr = 0,
           .p_memsz = sizeof(ElfW(NhdrGNUProperty)) - 1,  // Invalid
       },
       {.p_type = PT_NULL},
   };

   reset_error_buffer();
   auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ("PT_GNU_PROPERTY segment is too small. Segment size is 15, minimum is 16.");
 }

 // Tests that advertised n_descsz should still fit into p_memsz.
 TEST(note_gnu_property, pt_gnu_property_too_small) {
   ElfW(NhdrGNUProperty) prop = {
       .nhdr = {.n_namesz = PT_GNU_PROPERTY, .n_descsz = 1, .n_type = NT_GNU_PROPERTY_TYPE_0},
       .n_name = "GNU",
   };
   ElfW(Phdr) phdrs[] = {
       {
           .p_type = PT_GNU_PROPERTY,
           .p_vaddr = reinterpret_cast<ElfW(Addr)>(&prop),
           .p_memsz = sizeof(ElfW(NhdrGNUProperty)),  // Off by one
       },
   };

   reset_error_buffer();
   auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ("PT_GNU_PROPERTY segment p_memsz (16) is too small for note n_descsz (1).");
 }

 // Tests the validity check for invalid .note.gnu.property type.
 TEST(note_gnu_property, pt_gnu_property_bad_type) {
   ElfW(NhdrGNUProperty) prop = {
       .nhdr =
           {
               .n_namesz = 4,
               .n_descsz = 0,
               .n_type = NT_GNU_PROPERTY_TYPE_0 - 1  // Invalid
           },
       .n_name = "GNU",
   };
   PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected note type. Expected 5, got 4.");
 }

 // Tests the validity check for invalid .note.gnu.property name size.
 TEST(note_gnu_property, pt_gnu_property_bad_namesz) {
   ElfW(NhdrGNUProperty) prop = {
       .nhdr = {.n_namesz = 3,  // Invalid
                .n_descsz = 0,
                .n_type = NT_GNU_PROPERTY_TYPE_0},
       .n_name = "GNU",
   };
   PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected name size. Expected 4, got 3.");
 }

 // Tests the validity check for invalid .note.gnu.property name.
 TEST(note_gnu_property, pt_gnu_property_bad_name) {
   ElfW(NhdrGNUProperty) prop = {
       .nhdr = {.n_namesz = 4, .n_descsz = 0, .n_type = NT_GNU_PROPERTY_TYPE_0},
       .n_name = "ABC",  // Invalid
   };
   PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected name. Expected 'GNU', got 'ABC'.");
 }

 // Tests the validity check for not enough space for a Program Property header.
 TEST(note_gnu_property, pt_gnu_property_pphdr_no_space) {
   ElfW(NhdrGNUProperty) prop = {
       .nhdr = {.n_namesz = 4,
                .n_descsz = 7,  // Invalid
                .n_type = NT_GNU_PROPERTY_TYPE_0},
       .n_name = "GNU",
   };
   PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ(".note.gnu.property: no more space left for a Program Property Note header.");
 }

 // Tests an empty .note.gnu.property.
 TEST(note_gnu_property, pt_gnu_property_no_data) {
   GnuPropertySectionBuilder prop;
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   test_bti_not_supported(note);
   ASSERT_NO_ERROR_MSG();
 }

 // Tests a .note.gnu.property section with elements with pr_datasz = 0.
 TEST(note_gnu_property, pt_gnu_property_no_prop) {
   GnuPropertySectionBuilder prop;
   ASSERT_TRUE(prop.push(1, 0, (void*)nullptr));
   ASSERT_TRUE(prop.push(2, 0, (void*)nullptr));
   ASSERT_TRUE(prop.push(3, 0, (void*)nullptr));
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   test_bti_not_supported(note);
   ASSERT_NO_ERROR_MSG();
 }

 // Tests that GNU_PROPERTY_AARCH64_FEATURE_1_AND must have pr_datasz = 4.
 TEST(note_gnu_property, pt_gnu_property_bad_pr_datasz) {
 #if defined(__aarch64__)
   GnuPropertySectionBuilder prop;
   ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI, 0, 0};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, 12, &pr_data));
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   test_bti_not_supported(note);
   ASSERT_ERROR_MSG_EQ(
       ".note.gnu.property: property descriptor size is invalid. Expected 4 bytes for "
       "GNU_PROPERTY_AARCH64_FEATURE_1_AND, got 12.");
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }

 // Tests a .note.gnu.property section with only GNU_PROPERTY_AARCH64_FEATURE_1_BTI property array.
 TEST(note_gnu_property, pt_gnu_property_ok_1) {
 #if defined(__aarch64__)
   GnuPropertySectionBuilder prop;
   ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   ASSERT_NO_ERROR_MSG();
   test_bti_supported(note);
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }

 // Tests a .note.gnu.property section with only GNU_PROPERTY_AARCH64_FEATURE_1_BTI property array.
 TEST(note_gnu_property, pt_gnu_property_ok_2) {
 #if defined(__aarch64__)
   GnuPropertySectionBuilder prop;
   ElfW(Word) pr_data[] = {static_cast<ElfW(Word)>(~GNU_PROPERTY_AARCH64_FEATURE_1_BTI)};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   ASSERT_NO_ERROR_MSG();
   test_bti_not_supported(note);
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }

 // Tests a .note.gnu.property section with more property arrays.
 TEST(note_gnu_property, pt_gnu_property_ok_3) {
 #if defined(__aarch64__)
   GnuPropertySectionBuilder prop;

   ElfW(Word) pr_data_0[8] = {0xCD};
   ASSERT_TRUE(prop.push(1, 4, &pr_data_0));
   ASSERT_TRUE(prop.push(2, 3, &pr_data_0));
   ASSERT_TRUE(prop.push(3, 8, &pr_data_0));

   ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));

   ASSERT_TRUE(prop.push(4, 1, &pr_data_0));

   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   ASSERT_NO_ERROR_MSG();
   test_bti_supported(note);
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }

 // Tests a .note.gnu.property but with bad property descriptor size.
 TEST(note_gnu_property, pt_gnu_property_bad_n_descsz) {
 #if defined(__aarch64__)
   GnuPropertySectionBuilder prop;
   ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));

   ElfW(Word) n_descsz;
   if (sizeof(ElfW(Addr)) == 4) {
     n_descsz = 11;
   } else {
     n_descsz = 15;
   }

   prop.corrupt_n_descsz(n_descsz);

   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   if (sizeof(ElfW(Addr)) == 4) {
     ASSERT_ERROR_MSG_EQ(
         ".note.gnu.property: property descriptor size is invalid. Expected at least 12 bytes, got "
         "11.");
   } else {
     ASSERT_ERROR_MSG_EQ(
         ".note.gnu.property: property descriptor size is invalid. Expected at least 16 bytes, got "
         "15.");
   }
   test_bti_not_supported(note);
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }

 // Tests if platform support is missing.
 TEST(note_gnu_property, no_platform_support) {
 #if defined(__aarch64__)
   auto bti_supported_orig = g_platform_properties.bti_supported;
   g_platform_properties.bti_supported = false;

   GnuPropertySectionBuilder prop;
   ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
   ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
   PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
   ASSERT_NO_ERROR_MSG();
   test_bti_not_supported(note);

   g_platform_properties.bti_supported = bti_supported_orig;
 #else
   GTEST_SKIP() << "BTI is not supported on this architecture.";
 #endif
 }
	/*
	* Copyright (C) 2020 The Android Open Source Project
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
	* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
	* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
	* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	#include <stdlib.h>
	#include <iostream>
	#include <sstream>
	#include <string>

	#include <gtest/gtest.h>

	#include "linker.h"
	#include "linker_globals.h"
	#include "linker_note_gnu_property.h"
	#include "platform/bionic/macros.h"

	#define SONAME "test_so"

	static char error_buffer[1024];

	char* linker_get_error_buffer() {
	return error_buffer;
	}

	size_t linker_get_error_buffer_size() {
	return std::size(error_buffer);
	}

	static void reset_error_buffer() {
	error_buffer[0] = '\0';
	}

	platform_properties g_platform_properties {
	#if defined(__aarch64__)
	// Assume "hardware" supports Armv8.5-A BTI.
	.bti_supported = true
	#endif
	};

	// Helper macro to make the test cleaner.
	#define PHDR_WITH_NOTE_GNU_PROPERTY(__prop) \
	reset_error_buffer(); \
	ElfW(Phdr) phdrs[] = { \
	{.p_type = PT_LOAD}, \
	{ \
	.p_type = PT_GNU_PROPERTY, \
	.p_vaddr = reinterpret_cast<ElfW(Addr)>(__prop), \
	.p_memsz = sizeof(ElfW(NhdrGNUProperty)) + (__prop)->nhdr.n_descsz, \
	}, \
	{.p_type = PT_NULL}, \
	}; \
	auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME)

	// Helper to check for no error message.
	#define ASSERT_NO_ERROR_MSG() ASSERT_STREQ(error_buffer, "")

	// Helper to check expected error message.
	#define ASSERT_ERROR_MSG_EQ(__expected) ASSERT_STREQ(error_buffer, "\"" SONAME "\" " __expected)

	static void test_bti_not_supported(GnuPropertySection& note __unused) {
	#if defined(__aarch64__)
	ASSERT_FALSE(note.IsBTICompatible());
	#endif
	}

	#if defined(__aarch64__)
	static void test_bti_supported(GnuPropertySection& note __unused) {
	ASSERT_TRUE(note.IsBTICompatible());
	}
	#endif

	// Helper class to build a well-formed .note.gnu.property section.
	class GnuPropertySectionBuilder {
	public:
	GnuPropertySectionBuilder() {
	note = reinterpret_cast<ElfW(NhdrGNUProperty)*>(&section[0]);
	note->nhdr.n_namesz = 4;
	note->nhdr.n_descsz = 0;
	note->nhdr.n_type = NT_GNU_PROPERTY_TYPE_0;
	memcpy(note->n_name, "GNU", 4);
	}

	template <typename T>
	bool push(ElfW(Word) pr_type, ElfW(Word) pr_datasz, const T* pr_data) {
	// Must be aligned.
	const uintptr_t addition = align_up(pr_datasz, sizeof(ElfW(Addr)));
	if ((offset() + addition) > kMaxSectionSize) {
	return false;
	}
	++entries;
	ElfW(Prop)* prop = reinterpret_cast<ElfW(Prop)*>(&section[offset()]);
	// Header
	prop->pr_type = pr_type;
	prop->pr_datasz = pr_datasz;
	step(2 * sizeof(ElfW(Word)));
	// Data
	memcpy(&section[offset()], reinterpret_cast<const void*>(pr_data), pr_datasz);
	step(pr_datasz);
	// Padding
	memset(&section[offset()], 0xAA, addition - pr_datasz);
	step(addition - pr_datasz);
	return true;
	}

	ElfW(NhdrGNUProperty)* data() const { return note; }

	void dump() const {
	std::cout << ".note.gnu.property\n";
	dump_member("n_namesz", note->nhdr.n_namesz);
	dump_member("n_descsz", note->nhdr.n_descsz);
	dump_member("n_type ", note->nhdr.n_type);
	dump_member("n_name ", note->n_name);
	dump_member("entries ", entries);
	if (entries > 0) {
	std::cout << " raw data:";
	const uintptr_t offset = note->nhdr.n_descsz + 16;
	for (uintptr_t offs = 16; offs < offset; ++offs) {
	std::cout << std::hex;
	if ((offs % 8) == 0) {
	std::cout << "\n ";
	}
	auto value = static_cast<unsigned>(section[offs]);
	std::cout << " ";
	if (value < 0x10) {
	std::cout << "0";
	}
	std::cout << static_cast<unsigned>(section[offs]);
	}
	std::cout << std::dec << "\n";
	}
	}

	void corrupt_n_descsz(ElfW(Word) n_descsz) { note->nhdr.n_descsz = n_descsz; }

	private:
	template <typename T>
	void dump_member(const char* name, T value) const {
	std::cout << " " << name << " " << value << "\n";
	}

	ElfW(Word) offset() const { return note->nhdr.n_descsz + 16; }

	template <typename T>
	void step(T value) {
	note->nhdr.n_descsz += static_cast<ElfW(Word)>(value);
	}

	static const size_t kMaxSectionSize = 1024;

	alignas(8) uint8_t section[kMaxSectionSize];
	ElfW(NhdrGNUProperty)* note;
	size_t entries = 0;
	};

	// Tests that the default constructed instance does not report support
	// for Armv8.5-A BTI.
	TEST(note_gnu_property, default) {
	GnuPropertySection note;
	test_bti_not_supported(note);
	ASSERT_NO_ERROR_MSG();
	}

	// Tests that an instance without valid phdr pointer does not report
	// support for Armv8.5-A BTI.
	TEST(note_gnu_property, phdr_null) {
	auto note = GnuPropertySection(nullptr, 0, 0, SONAME);
	test_bti_not_supported(note);
	ASSERT_NO_ERROR_MSG();
	}

	// Tests that an instance without finding PT_GNU_PROPERTY does not
	// report support for Armv8.5-A BTI.
	TEST(note_gnu_property, no_pt_gnu_property) {
	ElfW(Phdr) phdrs[] = {
	{.p_type = PT_LOAD},
	{.p_type = PT_NULL},
	};

	reset_error_buffer();
	auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
	test_bti_not_supported(note);
	ASSERT_NO_ERROR_MSG();
	}

	// Tests the validity check for invalid PT_GNU_PROPERTY size.
	TEST(note_gnu_property, pt_gnu_property_bad_size) {
	ElfW(Phdr) phdrs[] = {
	{.p_type = PT_LOAD},
	{
	.p_type = PT_GNU_PROPERTY,
	.p_vaddr = 0,
	.p_memsz = sizeof(ElfW(NhdrGNUProperty)) - 1, // Invalid
	},
	{.p_type = PT_NULL},
	};

	reset_error_buffer();
	auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ("PT_GNU_PROPERTY segment is too small. Segment size is 15, minimum is 16.");
	}

	// Tests that advertised n_descsz should still fit into p_memsz.
	TEST(note_gnu_property, pt_gnu_property_too_small) {
	ElfW(NhdrGNUProperty) prop = {
	.nhdr = {.n_namesz = PT_GNU_PROPERTY, .n_descsz = 1, .n_type = NT_GNU_PROPERTY_TYPE_0},
	.n_name = "GNU",
	};
	ElfW(Phdr) phdrs[] = {
	{
	.p_type = PT_GNU_PROPERTY,
	.p_vaddr = reinterpret_cast<ElfW(Addr)>(&prop),
	.p_memsz = sizeof(ElfW(NhdrGNUProperty)), // Off by one
	},
	};

	reset_error_buffer();
	auto note = GnuPropertySection(&phdrs[0], std::size(phdrs), 0, SONAME);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ("PT_GNU_PROPERTY segment p_memsz (16) is too small for note n_descsz (1).");
	}

	// Tests the validity check for invalid .note.gnu.property type.
	TEST(note_gnu_property, pt_gnu_property_bad_type) {
	ElfW(NhdrGNUProperty) prop = {
	.nhdr =
	{
	.n_namesz = 4,
	.n_descsz = 0,
	.n_type = NT_GNU_PROPERTY_TYPE_0 - 1 // Invalid
	},
	.n_name = "GNU",
	};
	PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected note type. Expected 5, got 4.");
	}

	// Tests the validity check for invalid .note.gnu.property name size.
	TEST(note_gnu_property, pt_gnu_property_bad_namesz) {
	ElfW(NhdrGNUProperty) prop = {
	.nhdr = {.n_namesz = 3, // Invalid
	.n_descsz = 0,
	.n_type = NT_GNU_PROPERTY_TYPE_0},
	.n_name = "GNU",
	};
	PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected name size. Expected 4, got 3.");
	}

	// Tests the validity check for invalid .note.gnu.property name.
	TEST(note_gnu_property, pt_gnu_property_bad_name) {
	ElfW(NhdrGNUProperty) prop = {
	.nhdr = {.n_namesz = 4, .n_descsz = 0, .n_type = NT_GNU_PROPERTY_TYPE_0},
	.n_name = "ABC", // Invalid
	};
	PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ(".note.gnu.property: unexpected name. Expected 'GNU', got 'ABC'.");
	}

	// Tests the validity check for not enough space for a Program Property header.
	TEST(note_gnu_property, pt_gnu_property_pphdr_no_space) {
	ElfW(NhdrGNUProperty) prop = {
	.nhdr = {.n_namesz = 4,
	.n_descsz = 7, // Invalid
	.n_type = NT_GNU_PROPERTY_TYPE_0},
	.n_name = "GNU",
	};
	PHDR_WITH_NOTE_GNU_PROPERTY(&prop);
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ(".note.gnu.property: no more space left for a Program Property Note header.");
	}

	// Tests an empty .note.gnu.property.
	TEST(note_gnu_property, pt_gnu_property_no_data) {
	GnuPropertySectionBuilder prop;
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	test_bti_not_supported(note);
	ASSERT_NO_ERROR_MSG();
	}

	// Tests a .note.gnu.property section with elements with pr_datasz = 0.
	TEST(note_gnu_property, pt_gnu_property_no_prop) {
	GnuPropertySectionBuilder prop;
	ASSERT_TRUE(prop.push(1, 0, (void*)nullptr));
	ASSERT_TRUE(prop.push(2, 0, (void*)nullptr));
	ASSERT_TRUE(prop.push(3, 0, (void*)nullptr));
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	test_bti_not_supported(note);
	ASSERT_NO_ERROR_MSG();
	}

	// Tests that GNU_PROPERTY_AARCH64_FEATURE_1_AND must have pr_datasz = 4.
	TEST(note_gnu_property, pt_gnu_property_bad_pr_datasz) {
	#if defined(__aarch64__)
	GnuPropertySectionBuilder prop;
	ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI, 0, 0};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, 12, &pr_data));
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	test_bti_not_supported(note);
	ASSERT_ERROR_MSG_EQ(
	".note.gnu.property: property descriptor size is invalid. Expected 4 bytes for "
	"GNU_PROPERTY_AARCH64_FEATURE_1_AND, got 12.");
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}

	// Tests a .note.gnu.property section with only GNU_PROPERTY_AARCH64_FEATURE_1_BTI property array.
	TEST(note_gnu_property, pt_gnu_property_ok_1) {
	#if defined(__aarch64__)
	GnuPropertySectionBuilder prop;
	ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	ASSERT_NO_ERROR_MSG();
	test_bti_supported(note);
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}

	// Tests a .note.gnu.property section with only GNU_PROPERTY_AARCH64_FEATURE_1_BTI property array.
	TEST(note_gnu_property, pt_gnu_property_ok_2) {
	#if defined(__aarch64__)
	GnuPropertySectionBuilder prop;
	ElfW(Word) pr_data[] = {static_cast<ElfW(Word)>(~GNU_PROPERTY_AARCH64_FEATURE_1_BTI)};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	ASSERT_NO_ERROR_MSG();
	test_bti_not_supported(note);
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}

	// Tests a .note.gnu.property section with more property arrays.
	TEST(note_gnu_property, pt_gnu_property_ok_3) {
	#if defined(__aarch64__)
	GnuPropertySectionBuilder prop;

	ElfW(Word) pr_data_0[8] = {0xCD};
	ASSERT_TRUE(prop.push(1, 4, &pr_data_0));
	ASSERT_TRUE(prop.push(2, 3, &pr_data_0));
	ASSERT_TRUE(prop.push(3, 8, &pr_data_0));

	ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));

	ASSERT_TRUE(prop.push(4, 1, &pr_data_0));

	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	ASSERT_NO_ERROR_MSG();
	test_bti_supported(note);
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}

	// Tests a .note.gnu.property but with bad property descriptor size.
	TEST(note_gnu_property, pt_gnu_property_bad_n_descsz) {
	#if defined(__aarch64__)
	GnuPropertySectionBuilder prop;
	ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));

	ElfW(Word) n_descsz;
	if (sizeof(ElfW(Addr)) == 4) {
	n_descsz = 11;
	} else {
	n_descsz = 15;
	}

	prop.corrupt_n_descsz(n_descsz);

	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	if (sizeof(ElfW(Addr)) == 4) {
	ASSERT_ERROR_MSG_EQ(
	".note.gnu.property: property descriptor size is invalid. Expected at least 12 bytes, got "
	"11.");
	} else {
	ASSERT_ERROR_MSG_EQ(
	".note.gnu.property: property descriptor size is invalid. Expected at least 16 bytes, got "
	"15.");
	}
	test_bti_not_supported(note);
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}

	// Tests if platform support is missing.
	TEST(note_gnu_property, no_platform_support) {
	#if defined(__aarch64__)
	auto bti_supported_orig = g_platform_properties.bti_supported;
	g_platform_properties.bti_supported = false;

	GnuPropertySectionBuilder prop;
	ElfW(Word) pr_data[] = {GNU_PROPERTY_AARCH64_FEATURE_1_BTI};
	ASSERT_TRUE(prop.push(GNU_PROPERTY_AARCH64_FEATURE_1_AND, sizeof(pr_data), &pr_data));
	PHDR_WITH_NOTE_GNU_PROPERTY(prop.data());
	ASSERT_NO_ERROR_MSG();
	test_bti_not_supported(note);

	g_platform_properties.bti_supported = bti_supported_orig;
	#else
	GTEST_SKIP() << "BTI is not supported on this architecture.";
	#endif
	}