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authorJan de Mooij <jdemooij@mozilla.com>2018-04-10 15:00:49 +0200
committerwolfbeast <mcwerewolf@gmail.com>2018-04-19 12:01:40 +0200
commit9472136272f01b858412f2d9d7854d2daa82496f (patch)
tree3d446907848b183c3c49773ad0e976824c06d4b7 /js
parentf243b7b4af1242c2b80726e462bac045d70c37f0 (diff)
downloaduxp-9472136272f01b858412f2d9d7854d2daa82496f.tar.gz
Bug 1444668 - Avoid allocating large AssemblerBuffers. r=luke, r=bbouvier, a=RyanVM
Diffstat (limited to 'js')
-rw-r--r--js/src/jit/MacroAssembler.cpp6
-rw-r--r--js/src/jit/ProcessExecutableMemory.cpp8
-rw-r--r--js/src/jit/ProcessExecutableMemory.h8
-rw-r--r--js/src/jit/shared/IonAssemblerBuffer.h4
-rw-r--r--js/src/jit/x86-shared/AssemblerBuffer-x86-shared.h32
5 files changed, 49 insertions, 9 deletions
diff --git a/js/src/jit/MacroAssembler.cpp b/js/src/jit/MacroAssembler.cpp
index f633b9b7b9..9dbbe76242 100644
--- a/js/src/jit/MacroAssembler.cpp
+++ b/js/src/jit/MacroAssembler.cpp
@@ -2214,6 +2214,12 @@ MacroAssembler::finish()
}
MacroAssemblerSpecific::finish();
+
+ MOZ_RELEASE_ASSERT(size() <= MaxCodeBytesPerProcess,
+ "AssemblerBuffer should ensure we don't exceed MaxCodeBytesPerProcess");
+
+ if (bytesNeeded() > MaxCodeBytesPerProcess)
+ setOOM();
}
void
diff --git a/js/src/jit/ProcessExecutableMemory.cpp b/js/src/jit/ProcessExecutableMemory.cpp
index 71c2ab0dce..301541541e 100644
--- a/js/src/jit/ProcessExecutableMemory.cpp
+++ b/js/src/jit/ProcessExecutableMemory.cpp
@@ -385,14 +385,6 @@ class PageBitSet
#endif
};
-// Limit on the number of bytes of executable memory to prevent JIT spraying
-// attacks.
-#if JS_BITS_PER_WORD == 32
-static const size_t MaxCodeBytesPerProcess = 128 * 1024 * 1024;
-#else
-static const size_t MaxCodeBytesPerProcess = 1 * 1024 * 1024 * 1024;
-#endif
-
// Per-process executable memory allocator. It reserves a block of memory of
// MaxCodeBytesPerProcess bytes, then allocates/deallocates pages from that.
//
diff --git a/js/src/jit/ProcessExecutableMemory.h b/js/src/jit/ProcessExecutableMemory.h
index 078ce7cb75..a0e2fab985 100644
--- a/js/src/jit/ProcessExecutableMemory.h
+++ b/js/src/jit/ProcessExecutableMemory.h
@@ -17,6 +17,14 @@ namespace jit {
// alignment though.
static const size_t ExecutableCodePageSize = 64 * 1024;
+// Limit on the number of bytes of executable memory to prevent JIT spraying
+// attacks.
+#if JS_BITS_PER_WORD == 32
+static const size_t MaxCodeBytesPerProcess = 128 * 1024 * 1024;
+#else
+static const size_t MaxCodeBytesPerProcess = 1 * 1024 * 1024 * 1024;
+#endif
+
enum class ProtectionSetting {
Protected, // Not readable, writable, or executable.
Writable,
diff --git a/js/src/jit/shared/IonAssemblerBuffer.h b/js/src/jit/shared/IonAssemblerBuffer.h
index cc20e26d21..3a65526968 100644
--- a/js/src/jit/shared/IonAssemblerBuffer.h
+++ b/js/src/jit/shared/IonAssemblerBuffer.h
@@ -181,6 +181,10 @@ class AssemblerBuffer
protected:
virtual Slice* newSlice(LifoAlloc& a) {
+ if (size() > MaxCodeBytesPerProcess - sizeof(Slice)) {
+ fail_oom();
+ return nullptr;
+ }
Slice* tmp = static_cast<Slice*>(a.alloc(sizeof(Slice)));
if (!tmp) {
fail_oom();
diff --git a/js/src/jit/x86-shared/AssemblerBuffer-x86-shared.h b/js/src/jit/x86-shared/AssemblerBuffer-x86-shared.h
index 8cb5577848..fe678fc7db 100644
--- a/js/src/jit/x86-shared/AssemblerBuffer-x86-shared.h
+++ b/js/src/jit/x86-shared/AssemblerBuffer-x86-shared.h
@@ -68,6 +68,33 @@ namespace js {
namespace jit {
+ // AllocPolicy for AssemblerBuffer. OOMs when trying to allocate more than
+ // MaxCodeBytesPerProcess bytes. Use private inheritance to make sure we
+ // explicitly have to expose SystemAllocPolicy methods.
+ class AssemblerBufferAllocPolicy : private SystemAllocPolicy
+ {
+ public:
+ using SystemAllocPolicy::checkSimulatedOOM;
+ using SystemAllocPolicy::reportAllocOverflow;
+ using SystemAllocPolicy::free_;
+
+ template <typename T> T* pod_realloc(T* p, size_t oldSize, size_t newSize) {
+ static_assert(sizeof(T) == 1,
+ "AssemblerBufferAllocPolicy should only be used with byte vectors");
+ MOZ_ASSERT(oldSize <= MaxCodeBytesPerProcess);
+ if (MOZ_UNLIKELY(newSize > MaxCodeBytesPerProcess))
+ return nullptr;
+ return SystemAllocPolicy::pod_realloc<T>(p, oldSize, newSize);
+ }
+ template <typename T> T* pod_malloc(size_t numElems) {
+ static_assert(sizeof(T) == 1,
+ "AssemblerBufferAllocPolicy should only be used with byte vectors");
+ if (MOZ_UNLIKELY(numElems > MaxCodeBytesPerProcess))
+ return nullptr;
+ return SystemAllocPolicy::pod_malloc<T>(numElems);
+ }
+ };
+
class AssemblerBuffer
{
template<size_t size, typename T>
@@ -93,6 +120,9 @@ namespace jit {
void ensureSpace(size_t space)
{
+ // This should only be called with small |space| values to ensure
+ // we don't overflow below.
+ MOZ_ASSERT(space <= 16);
if (MOZ_UNLIKELY(!m_buffer.reserve(m_buffer.length() + space)))
oomDetected();
}
@@ -168,7 +198,7 @@ namespace jit {
m_buffer.clear();
}
- PageProtectingVector<unsigned char, 256, SystemAllocPolicy> m_buffer;
+ PageProtectingVector<unsigned char, 256, AssemblerBufferAllocPolicy> m_buffer;
bool m_oom;
};