Reviewers: Vyacheslav Egorov,
Description:
Add hinting to improve ASLR for macos (all allocations) and linux (newly
added
allocation types).
TEST=N/A
BUG=1749
Please review this at http://codereview.chromium.org/8115014/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/platform-linux.cc
M src/platform-macos.cc
Index: src/platform-linux.cc
===================================================================
--- src/platform-linux.cc (revision 9508)
+++ src/platform-linux.cc (working copy)
@@ -456,7 +456,8 @@
int size = ftell(file);
void* memory =
- mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+ mmap(GetRandomMmapAddr(), size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
@@ -471,7 +472,8 @@
return NULL;
}
void* memory =
- mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+ mmap(GetRandomMmapAddr(), size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
@@ -556,8 +558,8 @@
// kernel log.
int size = sysconf(_SC_PAGESIZE);
FILE* f = fopen(kGCFakeMmap, "w+");
- void* addr = mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_PRIVATE,
- fileno(f), 0);
+ void* addr = mmap(GetRandomMmapAddr(), size, PROT_READ | PROT_EXEC,
+ MAP_PRIVATE, fileno(f), 0);
ASSERT(addr != MAP_FAILED);
OS::Free(addr, size);
fclose(f);
Index: src/platform-macos.cc
===================================================================
--- src/platform-macos.cc (revision 9508)
+++ src/platform-macos.cc (working copy)
@@ -92,14 +92,32 @@
static Mutex* limit_mutex = NULL;
+static void* GetRandomMmapAddr() {
+ Isolate* isolate = Isolate::UncheckedCurrent();
+ // Note that the current isolate isn't set up in a call path via
+ // CpuFeatures::Probe. We don't care about randomization in this case
because
+ // the code page is immediately freed.
+ if (isolate != NULL) {
+#ifdef V8_TARGET_ARCH_X64
+ uint64_t rnd1 = V8::RandomPrivate(isolate);
+ uint64_t rnd2 = V8::RandomPrivate(isolate);
+ uint64_t rnd2 = V8::RandomPrivate(isolate);
+ raw_addr &= V8_UINT64_C(0x3ffffffff000);
+#else
+ uint32_t raw_addr = V8::RandomPrivate(isolate);
+ // The range 0x20000000 - 0x60000000 is relatively unpopulated on macos
+ // 10.6 and 10.7.
+ raw_addr &= 0x3ffff000;
+ raw_addr += 0x20000000;
+#endif
+ return reinterpret_cast<void*>(raw_addr);
+ }
+ return NULL;
+}
void OS::Setup() {
- // Seed the random number generator.
- // Convert the current time to a 64-bit integer first, before converting
it
- // to an unsigned. Going directly will cause an overflow and the seed to
be
- // set to all ones. The seed will be identical for different instances
that
- // call this setup code within the same millisecond.
- uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
+ // Seed the random number generator. We preserve microsecond resolution.
+ uint64_t seed = Ticks() ^ (getpid() << 16);
srandom(static_cast<unsigned int>(seed));
limit_mutex = CreateMutex();
}
@@ -148,7 +166,7 @@
bool is_executable) {
const size_t msize = RoundUp(requested, getpagesize());
int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
- void* mbase = mmap(NULL, msize, prot,
+ void* mbase = mmap(GetRandomMmapAddr(), msize, prot,
MAP_PRIVATE | MAP_ANON,
kMmapFd, kMmapFdOffset);
if (mbase == MAP_FAILED) {
@@ -207,7 +225,8 @@
int size = ftell(file);
void* memory =
- mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+ mmap(GetRandomMmapAddr(), size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
@@ -222,7 +241,8 @@
return NULL;
}
void* memory =
- mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+ mmap(GetRandomMmapAddr(), size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
@@ -346,7 +366,7 @@
ASSERT(IsAligned(alignment,
static_cast<intptr_t>(OS::AllocateAlignment())));
size_t request_size = RoundUp(size + alignment,
static_cast<intptr_t>(OS::AllocateAlignment()));
- void* reservation = mmap(NULL,
+ void* reservation = mmap(GetRandomMmapAddr(),
request_size,
PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
@@ -397,7 +417,7 @@
void* VirtualMemory::ReserveRegion(size_t size) {
- void* result = mmap(NULL,
+ void* result = mmap(GetRandomMmapAddr(),
size,
PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
--
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