[asan] Use dynamic shadow on 32-bit Android.
Summary:
The following kernel change has moved ET_DYN base to 0x4000000 on arm32:
https://marc.info/?l=linux-kernel&m=149825162606848&w=2
Switch to dynamic shadow base to avoid such conflicts in the future.
Reserve shadow memory in an ifunc resolver, but don't use it in the instrumentation
until PR35221 is fixed. This will eventually let use save one load per function.
Reviewers: kcc
Subscribers: aemerson, srhines, kubamracek, kristof.beyls, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D39393
llvm-svn: 317943
diff --git a/compiler-rt/lib/asan/CMakeLists.txt b/compiler-rt/lib/asan/CMakeLists.txt
index 3342357..9291e71 100644
--- a/compiler-rt/lib/asan/CMakeLists.txt
+++ b/compiler-rt/lib/asan/CMakeLists.txt
@@ -21,6 +21,7 @@
asan_memory_profile.cc
asan_poisoning.cc
asan_posix.cc
+ asan_premap_shadow.cc
asan_report.cc
asan_rtl.cc
asan_shadow_setup.cc
diff --git a/compiler-rt/lib/asan/asan_init_version.h b/compiler-rt/lib/asan/asan_init_version.h
index f48cc19..c49fcd7 100644
--- a/compiler-rt/lib/asan/asan_init_version.h
+++ b/compiler-rt/lib/asan/asan_init_version.h
@@ -15,6 +15,8 @@
#ifndef ASAN_INIT_VERSION_H
#define ASAN_INIT_VERSION_H
+#include "sanitizer_common/sanitizer_platform.h"
+
extern "C" {
// Every time the ASan ABI changes we also change the version number in the
// __asan_init function name. Objects built with incompatible ASan ABI
@@ -32,7 +34,12 @@
// v6=>v7: added 'odr_indicator' to __asan_global
// v7=>v8: added '__asan_(un)register_image_globals' functions for dead
// stripping support on Mach-O platforms
+#if SANITIZER_WORDSIZE == 32 && SANITIZER_ANDROID
+ // v8=>v9: 32-bit Android switched to dynamic shadow
+ #define __asan_version_mismatch_check __asan_version_mismatch_check_v9
+#else
#define __asan_version_mismatch_check __asan_version_mismatch_check_v8
+#endif
}
#endif // ASAN_INIT_VERSION_H
diff --git a/compiler-rt/lib/asan/asan_linux.cc b/compiler-rt/lib/asan/asan_linux.cc
index a949a98..902c64c 100644
--- a/compiler-rt/lib/asan/asan_linux.cc
+++ b/compiler-rt/lib/asan/asan_linux.cc
@@ -17,6 +17,7 @@
#include "asan_interceptors.h"
#include "asan_internal.h"
+#include "asan_premap_shadow.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_freebsd.h"
@@ -81,10 +82,37 @@
return &_DYNAMIC; // defined in link.h
}
+#if ASAN_PREMAP_SHADOW
uptr FindDynamicShadowStart() {
- UNREACHABLE("FindDynamicShadowStart is not available");
- return 0;
+ uptr granularity = GetMmapGranularity();
+ uptr shadow_start = reinterpret_cast<uptr>(&__asan_shadow);
+ uptr shadow_size = PremapShadowSize();
+ UnmapOrDie((void *)(shadow_start - granularity), shadow_size + granularity);
+ // MmapNoAccess does not touch TotalMmap, but UnmapOrDie decreases it.
+ // Compensate.
+ IncreaseTotalMmap(shadow_size + granularity);
+ return shadow_start;
}
+#else
+uptr FindDynamicShadowStart() {
+ uptr granularity = GetMmapGranularity();
+ uptr alignment = granularity * 8;
+ uptr left_padding = granularity;
+ uptr shadow_size = kHighShadowEnd + left_padding;
+ uptr map_size = shadow_size + alignment;
+
+ uptr map_start = (uptr)MmapNoAccess(map_size);
+ CHECK_NE(map_start, ~(uptr)0);
+
+ uptr shadow_start = RoundUpTo(map_start, alignment);
+ UnmapOrDie((void *)map_start, map_size);
+ // MmapNoAccess does not touch TotalMmap, but UnmapOrDie decreases it.
+ // Compensate.
+ IncreaseTotalMmap(map_size);
+
+ return shadow_start;
+}
+#endif
void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
UNIMPLEMENTED();
diff --git a/compiler-rt/lib/asan/asan_mapping.h b/compiler-rt/lib/asan/asan_mapping.h
index fcd9511..febe090 100644
--- a/compiler-rt/lib/asan/asan_mapping.h
+++ b/compiler-rt/lib/asan/asan_mapping.h
@@ -156,7 +156,7 @@
# define SHADOW_OFFSET (0)
#elif SANITIZER_WORDSIZE == 32
# if SANITIZER_ANDROID
-# define SHADOW_OFFSET (0)
+# define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
# elif defined(__mips__)
# define SHADOW_OFFSET kMIPS32_ShadowOffset32
# elif SANITIZER_FREEBSD
@@ -200,6 +200,12 @@
# endif
#endif
+#if SANITIZER_ANDROID && defined(__arm__)
+# define ASAN_PREMAP_SHADOW 1
+#else
+# define ASAN_PREMAP_SHADOW 0
+#endif
+
#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
diff --git a/compiler-rt/lib/asan/asan_premap_shadow.cc b/compiler-rt/lib/asan/asan_premap_shadow.cc
new file mode 100644
index 0000000..0e66eee
--- /dev/null
+++ b/compiler-rt/lib/asan/asan_premap_shadow.cc
@@ -0,0 +1,69 @@
+//===-- asan_premap_shadow.cc ---------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// Reserve shadow memory with an ifunc resolver.
+//===----------------------------------------------------------------------===//
+
+#include "asan_mapping.h"
+
+#if ASAN_PREMAP_SHADOW
+
+#include "asan_premap_shadow.h"
+#include "sanitizer_common/sanitizer_posix.h"
+
+namespace __asan {
+
+// The code in this file needs to run in an unrelocated binary. It may not
+// access any external symbol, including its own non-hidden globals.
+
+// Conservative upper limit.
+uptr PremapShadowSize() {
+ return GetMaxVirtualAddress() >> SHADOW_SCALE;
+}
+
+// Returns an address aligned to 8 pages, such that one page on the left and
+// PremapShadowSize() bytes on the right of it are mapped r/o.
+uptr PremapShadow() {
+ uptr granularity = GetMmapGranularity();
+ uptr alignment = granularity * 8;
+ uptr left_padding = granularity;
+ uptr shadow_size = PremapShadowSize();
+ uptr map_size = shadow_size + left_padding + alignment;
+
+ uptr map_start = (uptr)MmapNoAccess(map_size);
+ CHECK_NE(map_start, ~(uptr)0);
+
+ uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
+ uptr shadow_end = shadow_start + shadow_size;
+ internal_munmap(reinterpret_cast<void *>(map_start),
+ shadow_start - left_padding - map_start);
+ internal_munmap(reinterpret_cast<void *>(shadow_end),
+ map_start + map_size - shadow_end);
+ return shadow_start;
+}
+
+} // namespace __asan
+
+extern "C" {
+decltype(__asan_shadow)* __asan_premap_shadow() {
+ // The resolver may be called multiple times. Map the shadow just once.
+ static uptr premapped_shadow = 0;
+ if (!premapped_shadow) premapped_shadow = __asan::PremapShadow();
+ return reinterpret_cast<decltype(__asan_shadow)*>(premapped_shadow);
+}
+
+// __asan_shadow is a "function" that has the same address as the first byte of
+// the shadow mapping.
+INTERFACE_ATTRIBUTE __attribute__((ifunc("__asan_premap_shadow"))) void
+__asan_shadow();
+}
+
+#endif // ASAN_PREMAP_SHADOW
diff --git a/compiler-rt/lib/asan/asan_premap_shadow.h b/compiler-rt/lib/asan/asan_premap_shadow.h
new file mode 100644
index 0000000..6349e04
--- /dev/null
+++ b/compiler-rt/lib/asan/asan_premap_shadow.h
@@ -0,0 +1,28 @@
+//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// Premap shadow range with an ifunc resolver.
+//===----------------------------------------------------------------------===//
+
+
+#ifndef ASAN_PREMAP_SHADOW_H
+#define ASAN_PREMAP_SHADOW_H
+
+#if ASAN_PREMAP_SHADOW
+namespace __asan {
+// Conservative upper limit.
+uptr PremapShadowSize();
+}
+#endif
+
+extern "C" INTERFACE_ATTRIBUTE void __asan_shadow();
+
+#endif // ASAN_PREMAP_SHADOW_H
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index 9fb615f..746ba22 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -73,6 +73,7 @@
return PageSizeCached;
}
uptr GetMmapGranularity();
+uptr GetMaxVirtualAddress();
uptr GetMaxUserVirtualAddress();
// Threads
tid_t GetTid();
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
index c2ec29d..f42d219 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
@@ -34,7 +34,9 @@
};
// Functions to get/set global CommonFlags shared by all sanitizer runtimes:
-extern CommonFlags common_flags_dont_use;
+// FIXME: hidden needed for asan_premap_shadow. Consider building with
+// -fvisibility=hidden.
+extern CommonFlags common_flags_dont_use __attribute__((visibility("hidden")));
inline const CommonFlags *common_flags() {
return &common_flags_dont_use;
}
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cc b/compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cc
index 97dff0d..c03c993 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cc
@@ -191,6 +191,10 @@
return ShadowBounds.memory_limit - 1;
}
+uptr GetMaxVirtualAddress() {
+ return GetMaxUserVirtualAddress();
+}
+
static void *DoAnonymousMmapOrDie(uptr size, const char *mem_type,
bool raw_report, bool die_for_nomem) {
size = RoundUpTo(size, PAGE_SIZE);
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
index ea1e795..6274b24 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
@@ -954,7 +954,7 @@
}
#endif // SANITIZER_WORDSIZE == 32
-uptr GetMaxUserVirtualAddress() {
+uptr GetMaxVirtualAddress() {
#if SANITIZER_NETBSD && defined(__x86_64__)
return 0x7f7ffffff000ULL; // (0x00007f8000000000 - PAGE_SIZE)
#elif SANITIZER_WORDSIZE == 64
@@ -978,15 +978,21 @@
# if defined(__s390__)
return (1ULL << 31) - 1; // 0x7fffffff;
# else
- uptr res = (1ULL << 32) - 1; // 0xffffffff;
- if (!common_flags()->full_address_space)
- res -= GetKernelAreaSize();
- CHECK_LT(reinterpret_cast<uptr>(&res), res);
- return res;
+ return (1ULL << 32) - 1; // 0xffffffff;
# endif
#endif // SANITIZER_WORDSIZE
}
+uptr GetMaxUserVirtualAddress() {
+ uptr addr = GetMaxVirtualAddress();
+#if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
+ if (!common_flags()->full_address_space)
+ addr -= GetKernelAreaSize();
+ CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
+#endif
+ return addr;
+}
+
uptr GetPageSize() {
// Android post-M sysconf(_SC_PAGESIZE) crashes if called from .preinit_array.
#if SANITIZER_ANDROID
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
index 284b6cf..195a52c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
@@ -864,6 +864,10 @@
#endif // SANITIZER_WORDSIZE
}
+uptr GetMaxVirtualAddress() {
+ return GetMaxUserVirtualAddress();
+}
+
uptr FindAvailableMemoryRange(uptr shadow_size,
uptr alignment,
uptr left_padding,
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_win.cc b/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
index 1186971..dee1add 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_win.cc
@@ -70,6 +70,10 @@
return (uptr)si.lpMaximumApplicationAddress;
}
+uptr GetMaxVirtualAddress() {
+ return GetMaxUserVirtualAddress();
+}
+
bool FileExists(const char *filename) {
return ::GetFileAttributesA(filename) != INVALID_FILE_ATTRIBUTES;
}