[Scudo] [GWP-ASan] Add GWP-ASan to Scudo Standalone.
Summary:
Adds GWP-ASan to Scudo standalone. Default parameters are pulled across from the
GWP-ASan build. No backtrace support as of yet.
Reviewers: cryptoad, eugenis, pcc
Reviewed By: cryptoad
Subscribers: merge_guards_bot, mgorny, #sanitizers, llvm-commits, cferris, vlad.tsyrklevich, pcc
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D71229
GitOrigin-RevId: ed4618edb35688567fcf107785776e27028f4062
diff --git a/combined.h b/combined.h
index 53e0bf7..864436d 100644
--- a/combined.h
+++ b/combined.h
@@ -18,8 +18,19 @@
#include "quarantine.h"
#include "report.h"
#include "secondary.h"
+#include "string_utils.h"
#include "tsd.h"
+#ifdef GWP_ASAN_HOOKS
+# include "gwp_asan/guarded_pool_allocator.h"
+// GWP-ASan is declared here in order to avoid indirect call overhead. It's also
+// instantiated outside of the Allocator class, as the allocator is only
+// zero-initialised. GWP-ASan requires constant initialisation, and the Scudo
+// allocator doesn't have a constexpr constructor (see discussion here:
+// https://reviews.llvm.org/D69265#inline-624315).
+static gwp_asan::GuardedPoolAllocator GuardedAlloc;
+#endif // GWP_ASAN_HOOKS
+
namespace scudo {
template <class Params> class Allocator {
@@ -133,6 +144,22 @@
Quarantine.init(
static_cast<uptr>(getFlags()->quarantine_size_kb << 10),
static_cast<uptr>(getFlags()->thread_local_quarantine_size_kb << 10));
+
+#ifdef GWP_ASAN_HOOKS
+ gwp_asan::options::Options Opt;
+ Opt.Enabled = getFlags()->GWP_ASAN_Enabled;
+ // Bear in mind - Scudo has its own alignment guarantees that are strictly
+ // enforced. Scudo exposes the same allocation function for everything from
+ // malloc() to posix_memalign, so in general this flag goes unused, as Scudo
+ // will always ask GWP-ASan for an aligned amount of bytes.
+ Opt.PerfectlyRightAlign = getFlags()->GWP_ASAN_PerfectlyRightAlign;
+ Opt.MaxSimultaneousAllocations =
+ getFlags()->GWP_ASAN_MaxSimultaneousAllocations;
+ Opt.SampleRate = getFlags()->GWP_ASAN_SampleRate;
+ Opt.InstallSignalHandlers = getFlags()->GWP_ASAN_InstallSignalHandlers;
+ Opt.Printf = Printf;
+ GuardedAlloc.init(Opt);
+#endif // GWP_ASAN_HOOKS
}
void reset() { memset(this, 0, sizeof(*this)); }
@@ -164,6 +191,14 @@
uptr Alignment = MinAlignment,
bool ZeroContents = false) {
initThreadMaybe();
+
+#ifdef GWP_ASAN_HOOKS
+ if (UNLIKELY(GuardedAlloc.shouldSample())) {
+ if (void *Ptr = GuardedAlloc.allocate(roundUpTo(Size, Alignment)))
+ return Ptr;
+ }
+#endif // GWP_ASAN_HOOKS
+
ZeroContents |= static_cast<bool>(Options.ZeroContents);
if (UNLIKELY(Alignment > MaxAlignment)) {
@@ -261,6 +296,13 @@
// being destroyed properly. Any other heap operation will do a full init.
initThreadMaybe(/*MinimalInit=*/true);
+#ifdef GWP_ASAN_HOOKS
+ if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr))) {
+ GuardedAlloc.deallocate(Ptr);
+ return;
+ }
+#endif // GWP_ASAN_HOOKS
+
if (&__scudo_deallocate_hook)
__scudo_deallocate_hook(Ptr);
@@ -300,6 +342,17 @@
DCHECK_NE(OldPtr, nullptr);
DCHECK_NE(NewSize, 0);
+#ifdef GWP_ASAN_HOOKS
+ if (UNLIKELY(GuardedAlloc.pointerIsMine(OldPtr))) {
+ uptr OldSize = GuardedAlloc.getSize(OldPtr);
+ void *NewPtr = allocate(NewSize, Chunk::Origin::Malloc, Alignment);
+ if (NewPtr)
+ memcpy(NewPtr, OldPtr, (NewSize < OldSize) ? NewSize : OldSize);
+ GuardedAlloc.deallocate(OldPtr);
+ return NewPtr;
+ }
+#endif // GWP_ASAN_HOOKS
+
if (UNLIKELY(!isAligned(reinterpret_cast<uptr>(OldPtr), MinAlignment)))
reportMisalignedPointer(AllocatorAction::Reallocating, OldPtr);
@@ -446,6 +499,12 @@
initThreadMaybe();
if (UNLIKELY(!Ptr))
return 0;
+
+#ifdef GWP_ASAN_HOOKS
+ if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr)))
+ return GuardedAlloc.getSize(Ptr);
+#endif // GWP_ASAN_HOOKS
+
Chunk::UnpackedHeader Header;
Chunk::loadHeader(Cookie, Ptr, &Header);
// Getting the usable size of a chunk only makes sense if it's allocated.
@@ -464,6 +523,10 @@
// A corrupted chunk will not be reported as owned, which is WAI.
bool isOwned(const void *Ptr) {
initThreadMaybe();
+#ifdef GWP_ASAN_HOOKS
+ if (GuardedAlloc.pointerIsMine(Ptr))
+ return true;
+#endif // GWP_ASAN_HOOKS
if (!Ptr || !isAligned(reinterpret_cast<uptr>(Ptr), MinAlignment))
return false;
Chunk::UnpackedHeader Header;
diff --git a/flags.cpp b/flags.cpp
index 1e970ae..2540789 100644
--- a/flags.cpp
+++ b/flags.cpp
@@ -22,6 +22,13 @@
#define SCUDO_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
#include "flags.inc"
#undef SCUDO_FLAG
+
+#ifdef GWP_ASAN_HOOKS
+#define GWP_ASAN_OPTION(Type, Name, DefaultValue, Description) \
+ GWP_ASAN_##Name = DefaultValue;
+#include "gwp_asan/options.inc"
+#undef GWP_ASAN_OPTION
+#endif // GWP_ASAN_HOOKS
}
void registerFlags(FlagParser *Parser, Flags *F) {
@@ -30,6 +37,14 @@
reinterpret_cast<void *>(&F->Name));
#include "flags.inc"
#undef SCUDO_FLAG
+
+#ifdef GWP_ASAN_HOOKS
+#define GWP_ASAN_OPTION(Type, Name, DefaultValue, Description) \
+ Parser->registerFlag("GWP_ASAN_"#Name, Description, FlagType::FT_##Type, \
+ reinterpret_cast<void *>(&F->GWP_ASAN_##Name));
+#include "gwp_asan/options.inc"
+#undef GWP_ASAN_OPTION
+#endif // GWP_ASAN_HOOKS
}
static const char *getCompileDefinitionScudoDefaultOptions() {
diff --git a/flags.h b/flags.h
index edd39a1..2cd0a5b 100644
--- a/flags.h
+++ b/flags.h
@@ -17,6 +17,14 @@
#define SCUDO_FLAG(Type, Name, DefaultValue, Description) Type Name;
#include "flags.inc"
#undef SCUDO_FLAG
+
+#ifdef GWP_ASAN_HOOKS
+#define GWP_ASAN_OPTION(Type, Name, DefaultValue, Description) \
+ Type GWP_ASAN_##Name;
+#include "gwp_asan/options.inc"
+#undef GWP_ASAN_OPTION
+#endif // GWP_ASAN_HOOKS
+
void setDefaults();
};
diff --git a/flags_parser.h b/flags_parser.h
index 857b50e..32511f7 100644
--- a/flags_parser.h
+++ b/flags_parser.h
@@ -29,7 +29,7 @@
void printFlagDescriptions();
private:
- static const u32 MaxFlags = 12;
+ static const u32 MaxFlags = 16;
struct Flag {
const char *Name;
const char *Desc;
diff --git a/tests/flags_test.cpp b/tests/flags_test.cpp
index 45918ad..85ae422 100644
--- a/tests/flags_test.cpp
+++ b/tests/flags_test.cpp
@@ -117,3 +117,20 @@
EXPECT_TRUE(Flags.delete_size_mismatch);
EXPECT_EQ(2048, Flags.quarantine_max_chunk_size);
}
+
+TEST(ScudoFlagsTest, GWPASanFlags) {
+#ifndef GWP_ASAN_HOOKS
+ GTEST_SKIP() << "GWP-ASan wasn't built as part of Scudo Standalone.";
+#endif // GWP_ASAN_HOOKS
+
+ scudo::FlagParser Parser;
+ scudo::Flags Flags;
+ scudo::registerFlags(&Parser, &Flags);
+ Flags.setDefaults();
+ Flags.GWP_ASAN_Enabled = false;
+ Parser.parseString("GWP_ASAN_Enabled=true:GWP_ASAN_SampleRate=1:"
+ "GWP_ASAN_InstallSignalHandlers=false");
+ EXPECT_TRUE(Flags.GWP_ASAN_Enabled);
+ EXPECT_FALSE(Flags.GWP_ASAN_InstallSignalHandlers);
+ EXPECT_EQ(1, Flags.GWP_ASAN_SampleRate);
+}
