[asan] Check for pvalloc overlow

[cryptoad]

Summary

Last one of the pvalloc overflow checks!

CheckForPvallocOverflow was introduced with D35818 to detect when pvalloc
would wrap when rounding up to the next multiple of the page size.

Add this check to ASan's pvalloc implementation.

[cryptoad]

FYI this will break on google3 due to allocator_may_return_null set to 1 for tests by default, so won't submit as is.
Haven't figured out a way to get around this and have it work for both, except migrating to a lit test with ASAN_OPTIONS set accordingly.
WDYT?

[cryptoad]

Switching the test to a lit test to avoid breaking places with a different
allocator_may_return_null value.

lib/asan/asan_allocator.cc

 
 void *asan_valloc(uptr size, BufferedStackTrace *stack) {
   return SetErrnoOnNull(
       instance.Allocate(size, GetPageSizeCached(), stack, FROM_MALLOC, true));
 }
 
 void *asan_pvalloc(uptr size, BufferedStackTrace *stack) {
   uptr PageSize = GetPageSizeCached();
+  if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) {
+    errno = errno_ENOMEM;
+    return AsanAllocator::FailureHandler::OnBadRequest();
+  }
   // pvalloc(0) should allocate one page.
   size = size ? RoundUpTo(size, PageSize) : PageSize;
   return SetErrnoOnNull(
       instance.Allocate(size, PageSize, stack, FROM_MALLOC, true));
 }
 
 void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
                     AllocType alloc_type) {

test/asan/TestCases/Linux/pvalloc-overflow.cc

+// RUN: %clangxx_asan  %s -o %t
+// RUN: ASAN_OPTIONS=allocator_may_return_null=0 not %run %t m1 2>&1 | FileCheck %s
+// RUN: ASAN_OPTIONS=allocator_may_return_null=1     %run %t m1 2>&1
+// RUN: ASAN_OPTIONS=allocator_may_return_null=0 not %run %t psm1 2>&1 | FileCheck %s
+// RUN: ASAN_OPTIONS=allocator_may_return_null=1     %run %t psm1 2>&1
+
+// UNSUPPORTED: freebsd
+
+// Checks that pvalloc overflows are caught. If the allocator is allowed to
+// return null, the errno should be set to ENOMEM.
+
+#include <assert.h>
+#include <errno.h>
+#include <malloc.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[]) {
+  void *p;
+  size_t page_size;
+
+  assert(argc == 2);
+
+  page_size = sysconf(_SC_PAGESIZE);
+
+  if (!strcmp(argv[1], "m1")) {
+    p = pvalloc((uintptr_t)-1);
+    assert(!p);
+    assert(errno == ENOMEM);
+  }
+  if (!strcmp(argv[1], "psm1")) {
+    p = pvalloc((uintptr_t)-(page_size - 1));
+    assert(!p);
+    assert(errno == ENOMEM);
+  }
+
+  return 0;
+}
+
+// CHECK: AddressSanitizer's allocator is terminating the process