Merge "Update the _FORTIFY_SOURCE documentation." into main
diff --git a/libc/include/android/versioning.h b/libc/include/android/versioning.h
index cd61f33..64528e1 100644
--- a/libc/include/android/versioning.h
+++ b/libc/include/android/versioning.h
@@ -22,8 +22,8 @@
#define __INTRODUCED_IN(api_level) __attribute__((__annotate__("introduced_in=" #api_level)))
#define __INTRODUCED_IN_NO_GUARD_FOR_NDK(api_level) __attribute__((__annotate__("introduced_in=" #api_level))) __VERSIONER_NO_GUARD
-#define __DEPRECATED_IN(api_level) __attribute__((__annotate__("deprecated_in=" #api_level)))
-#define __REMOVED_IN(api_level) __attribute__((__annotate__("obsoleted_in=" #api_level)))
+#define __DEPRECATED_IN(api_level, ...) __attribute__((__annotate__("deprecated_in=" #api_level)))
+#define __REMOVED_IN(api_level, ...) __attribute__((__annotate__("obsoleted_in=" #api_level)))
#define __INTRODUCED_IN_32(api_level) __attribute__((__annotate__("introduced_in_32=" #api_level)))
#define __INTRODUCED_IN_64(api_level) __attribute__((__annotate__("introduced_in_64=" #api_level)))
@@ -47,16 +47,16 @@
// libc++ doesn't currently guard these calls. There's no risk to the apps though because using
// those APIs will still cause a link error.
#if defined(__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__)
-#define __BIONIC_AVAILABILITY(__what) __attribute__((__availability__(android,__what)))
+#define __BIONIC_AVAILABILITY(__what, ...) __attribute__((__availability__(android,__what __VA_OPT__(,) __VA_ARGS__)))
#define __INTRODUCED_IN_NO_GUARD_FOR_NDK(api_level) __INTRODUCED_IN(api_level)
#else
-#define __BIONIC_AVAILABILITY(__what) __attribute__((__availability__(android,strict,__what)))
+#define __BIONIC_AVAILABILITY(__what, ...) __attribute__((__availability__(android,strict,__what __VA_OPT__(,) __VA_ARGS__)))
#define __INTRODUCED_IN_NO_GUARD_FOR_NDK(api_level)
#endif
#define __INTRODUCED_IN(api_level) __BIONIC_AVAILABILITY(introduced=api_level)
-#define __DEPRECATED_IN(api_level) __BIONIC_AVAILABILITY(deprecated=api_level)
-#define __REMOVED_IN(api_level) __BIONIC_AVAILABILITY(obsoleted=api_level)
+#define __DEPRECATED_IN(api_level, ...) __BIONIC_AVAILABILITY(deprecated=api_level __VA_OPT__(,message=) __VA_ARGS__)
+#define __REMOVED_IN(api_level, ...) __BIONIC_AVAILABILITY(obsoleted=api_level __VA_OPT__(,message=) __VA_ARGS__)
// The same availability attribute can't be annotated multiple times. Therefore, the macros are
// defined for the configuration that it is valid for so that declarations like the below doesn't
@@ -80,5 +80,5 @@
// Vendor modules do not follow SDK versioning. Ignore NDK guards for vendor modules.
#if defined(__ANDROID_VENDOR__)
#undef __BIONIC_AVAILABILITY
-#define __BIONIC_AVAILABILITY(x)
+#define __BIONIC_AVAILABILITY(api_level, ...)
#endif // defined(__ANDROID_VENDOR__)
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 32264d6..78114c3 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -69,7 +69,7 @@
#define stderr stderr
#else
/* Before M the actual symbols for stdin and friends had different names. */
-extern FILE __sF[] __REMOVED_IN(23);
+extern FILE __sF[] __REMOVED_IN(23, "Use stdin/stdout/stderr");
#define stdin (&__sF[0])
#define stdout (&__sF[1])
diff --git a/libc/system_properties/system_properties.cpp b/libc/system_properties/system_properties.cpp
index 1dedb61..e0d38a8 100644
--- a/libc/system_properties/system_properties.cpp
+++ b/libc/system_properties/system_properties.cpp
@@ -337,31 +337,42 @@
int SystemProperties::Add(const char* name, unsigned int namelen, const char* value,
unsigned int valuelen) {
- if (valuelen >= PROP_VALUE_MAX && !is_read_only(name)) {
+ if (namelen < 1) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: name length 0");
return -1;
}
- if (namelen < 1) {
+ if (valuelen >= PROP_VALUE_MAX && !is_read_only(name)) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: \"%s\" value too long: %d >= PROP_VALUE_MAX",
+ name, valuelen);
return -1;
}
if (!initialized_) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: properties not initialized");
return -1;
}
prop_area* serial_pa = contexts_->GetSerialPropArea();
if (serial_pa == nullptr) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: property area not found");
return -1;
}
prop_area* pa = contexts_->GetPropAreaForName(name);
if (!pa) {
- async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: access denied for \"%s\"", name);
return -1;
}
- bool ret = pa->add(name, namelen, value, valuelen);
- if (!ret) {
+ if (!pa->add(name, namelen, value, valuelen)) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "__system_property_add failed: add failed for \"%s\"", name);
return -1;
}
diff --git a/linker/linker_crt_pad_segment_test.cpp b/linker/linker_crt_pad_segment_test.cpp
index 5a219f8..c11df50 100644
--- a/linker/linker_crt_pad_segment_test.cpp
+++ b/linker/linker_crt_pad_segment_test.cpp
@@ -72,13 +72,22 @@
}; // anonymous namespace
TEST(crt_pad_segment, note_absent) {
+ if (!page_size_migration_supported()) {
+ GTEST_SKIP() << "Kernel does not support page size migration";
+ }
ASSERT_FALSE(GetPadSegment("no_crt_pad_segment.so"));
}
TEST(crt_pad_segment, note_present_and_enabled) {
+ if (!page_size_migration_supported()) {
+ GTEST_SKIP() << "Kernel does not support page size migration";
+ }
ASSERT_TRUE(GetPadSegment("crt_pad_segment_enabled.so"));
}
TEST(crt_pad_segment, note_present_and_disabled) {
+ if (!page_size_migration_supported()) {
+ GTEST_SKIP() << "Kernel does not support page size migration";
+ }
ASSERT_FALSE(GetPadSegment("crt_pad_segment_disabled.so"));
}
diff --git a/linker/linker_phdr.cpp b/linker/linker_phdr.cpp
index ef7671c..fa712a1 100644
--- a/linker/linker_phdr.cpp
+++ b/linker/linker_phdr.cpp
@@ -46,6 +46,8 @@
#include "private/CFIShadow.h" // For kLibraryAlignment
#include "private/elf_note.h"
+#include <android-base/file.h>
+
static int GetTargetElfMachine() {
#if defined(__arm__)
return EM_ARM;
@@ -707,8 +709,28 @@
return true;
}
+/*
+ * Returns true if the kernel supports page size migration, else false.
+ */
+bool page_size_migration_supported() {
+ static bool pgsize_migration_enabled = []() {
+ std::string enabled;
+ if (!android::base::ReadFileToString("/sys/kernel/mm/pgsize_migration/enabled", &enabled)) {
+ return false;
+ }
+ return enabled.find("1") != std::string::npos;
+ }();
+ return pgsize_migration_enabled;
+}
+
// Find the ELF note of type NT_ANDROID_TYPE_PAD_SEGMENT and check that the desc value is 1.
bool ElfReader::ReadPadSegmentNote() {
+ if (!page_size_migration_supported()) {
+ // Don't attempt to read the note, since segment extension isn't
+ // supported; but return true so that loading can continue normally.
+ return true;
+ }
+
// The ELF can have multiple PT_NOTE's, check them all
for (size_t i = 0; i < phdr_num_; ++i) {
const ElfW(Phdr)* phdr = &phdr_table_[i];
@@ -773,7 +795,16 @@
const ElfW(Phdr)* next = nullptr;
size_t next_idx = phdr_idx + 1;
- if (phdr->p_align == kPageSize || !should_pad_segments) {
+ // Don't do segment extension for p_align > 64KiB, such ELFs already existed in the
+ // field e.g. 2MiB p_align for THPs and are relatively small in number.
+ //
+ // The kernel can only represent padding for p_align up to 64KiB. This is because
+ // the kernel uses 4 available bits in the vm_area_struct to represent padding
+ // extent; and so cannot enable mitigations to avoid breaking app compatibility for
+ // p_aligns > 64KiB.
+ //
+ // Don't perform segment extension on these to avoid app compatibility issues.
+ if (phdr->p_align <= kPageSize || phdr->p_align > 64*1024 || !should_pad_segments) {
return;
}
@@ -887,10 +918,28 @@
// 2) Break the COW backing, faulting in new anon pages for a region
// that will not be used.
- // _seg_file_end = unextended seg_file_end
- uint64_t _seg_file_end = seg_start + phdr->p_filesz;
- if ((phdr->p_flags & PF_W) != 0 && page_offset(_seg_file_end) > 0) {
- memset(reinterpret_cast<void*>(_seg_file_end), 0, kPageSize - page_offset(_seg_file_end));
+ uint64_t unextended_seg_file_end = seg_start + phdr->p_filesz;
+ if ((phdr->p_flags & PF_W) != 0 && page_offset(unextended_seg_file_end) > 0) {
+ memset(reinterpret_cast<void*>(unextended_seg_file_end), 0,
+ kPageSize - page_offset(unextended_seg_file_end));
+ }
+
+ // Pages may be brought in due to readahead.
+ // Drop the padding (zero) pages, to avoid reclaim work later.
+ //
+ // NOTE: The madvise() here is special, as it also serves to hint to the
+ // kernel the portion of the LOAD segment that is padding.
+ //
+ // See: [1] https://android-review.googlesource.com/c/kernel/common/+/3032411
+ // [2] https://android-review.googlesource.com/c/kernel/common/+/3048835
+ uint64_t pad_start = page_end(unextended_seg_file_end);
+ uint64_t pad_end = page_end(seg_file_end);
+ CHECK(pad_start <= pad_end);
+ uint64_t pad_len = pad_end - pad_start;
+ if (page_size_migration_supported() && pad_len > 0 &&
+ madvise(reinterpret_cast<void*>(pad_start), pad_len, MADV_DONTNEED)) {
+ DL_WARN("\"%s\": madvise(0x%" PRIx64 ", 0x%" PRIx64 ", MADV_DONTNEED) failed: %m",
+ name_.c_str(), pad_start, pad_len);
}
seg_file_end = page_end(seg_file_end);
diff --git a/linker/linker_phdr.h b/linker/linker_phdr.h
index 61242eb..aab9018 100644
--- a/linker/linker_phdr.h
+++ b/linker/linker_phdr.h
@@ -154,3 +154,5 @@
const char* phdr_table_get_interpreter_name(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias);
+
+bool page_size_migration_supported();
diff --git a/tests/clang_fortify_tests.cpp b/tests/clang_fortify_tests.cpp
index 544af43..f4ef4ac 100644
--- a/tests/clang_fortify_tests.cpp
+++ b/tests/clang_fortify_tests.cpp
@@ -164,9 +164,7 @@
const char large_string[] = "Hello!!!";
static_assert(sizeof(large_string) > sizeof(small_buffer), "");
-#if __clang_major__ > 13
- // expected-error@+3{{will always overflow}}
-#endif
+ // expected-error@+2{{will always overflow}}
// expected-error@+1{{string bigger than buffer}}
EXPECT_FORTIFY_DEATH(strcpy(small_buffer, large_string));
// expected-error@+1{{string bigger than buffer}}
@@ -204,9 +202,7 @@
static_assert(sizeof(small_string) > sizeof(split.tiny_buffer), "");
#if _FORTIFY_SOURCE > 1
-#if __clang_major__ > 13
- // expected-error@+4{{will always overflow}}
-#endif
+ // expected-error@+3{{will always overflow}}
// expected-error@+2{{string bigger than buffer}}
#endif
EXPECT_FORTIFY_DEATH_STRUCT(strcpy(split.tiny_buffer, small_string));