Index: lib/sanitizer_common/sanitizer_allocator_checks.h
===================================================================
--- lib/sanitizer_common/sanitizer_allocator_checks.h
+++ lib/sanitizer_common/sanitizer_allocator_checks.h
@@ -59,6 +59,12 @@
   return (max / size) < n;
 }
 
+// Returns true if the size passed to pvalloc overflows when rounded to the next
+// multiple of page_size.
+INLINE bool CheckForPvallocOverflow(uptr size, uptr page_size) {
+  return RoundUpTo(size, page_size) < size;
+}
+
 } // namespace __sanitizer
 
 #endif  // SANITIZER_ALLOCATOR_CHECKS_H
Index: lib/scudo/scudo_allocator.cpp
===================================================================
--- lib/scudo/scudo_allocator.cpp
+++ lib/scudo/scudo_allocator.cpp
@@ -665,6 +665,10 @@
 
 void *scudoPvalloc(uptr Size) {
   uptr PageSize = GetPageSizeCached();
+  if (UNLIKELY(CheckForPvallocOverflow(Size, PageSize))) {
+    errno = errno_ENOMEM;
+    return ScudoAllocator::FailureHandler::OnBadRequest();
+  }
   // pvalloc(0) should allocate one page.
   Size = Size ? RoundUpTo(Size, PageSize) : PageSize;
   return SetErrnoOnNull(Instance.allocate(Size, PageSize, FromMemalign));
Index: test/scudo/memalign.cpp
===================================================================
--- test/scudo/memalign.cpp
+++ test/scudo/memalign.cpp
@@ -8,17 +8,13 @@
 #include <assert.h>
 #include <errno.h>
 #include <malloc.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
-
-// Reduce the size of the quarantine, or the test can run out of aligned memory
-// on 32-bit for the larger alignments.
-extern "C" const char *__scudo_default_options() {
-  return "QuarantineSizeMb=1";
-}
+#include <unistd.h>
 
 // Sometimes the headers may not have this...
-extern "C" void *aligned_alloc (size_t alignment, size_t size);
+extern "C" void *aligned_alloc(size_t alignment, size_t size);
 
 int main(int argc, char **argv)
 {
@@ -32,9 +28,11 @@
   if (!strcmp(argv[1], "valid")) {
     posix_memalign(&p, alignment, size);
     assert(p);
+    assert(((uintptr_t)p & (alignment - 1)) == 0);
     free(p);
     p = aligned_alloc(alignment, size);
     assert(p);
+    assert(((uintptr_t)p & (alignment - 1)) == 0);
     free(p);
     // Tests various combinations of alignment and sizes
     for (int i = (sizeof(void *) == 4) ? 3 : 4; i < 19; i++) {
@@ -44,6 +42,7 @@
         for (int k = 0; k < 3; k++) {
           p = memalign(alignment, size - (2 * sizeof(void *) * k));
           assert(p);
+          assert(((uintptr_t)p & (alignment - 1)) == 0);
           free(p);
         }
       }
@@ -54,6 +53,7 @@
       for (int k = 0; k < 3; k++) {
         p = memalign(alignment, 0x1000 - (2 * sizeof(void *) * k));
         assert(p);
+        assert(((uintptr_t)p & (alignment - 1)) == 0);
         free(p);
       }
     }
Index: test/scudo/valloc.cpp
===================================================================
--- /dev/null
+++ test/scudo/valloc.cpp
@@ -0,0 +1,63 @@
+// RUN: %clang_scudo %s -o %t
+// RUN: %run %t valid   2>&1
+// RUN: %run %t invalid 2>&1
+
+// Tests that valloc and pvalloc work as intended.
+
+#include <assert.h>
+#include <errno.h>
+#include <malloc.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+size_t round_up_to(size_t size, size_t alignment) {
+  return (size + alignment - 1) & ~(alignment - 1);
+}
+
+int main(int argc, char **argv)
+{
+  void *p = nullptr;
+  size_t size, page_size;
+
+  assert(argc == 2);
+
+  page_size = sysconf(_SC_PAGESIZE);
+  // Check that the page size is a power of two.
+  assert((page_size & (page_size - 1)) == 0);
+
+  if (!strcmp(argv[1], "valid")) {
+    for (int i = (sizeof(void *) == 4) ? 3 : 4; i < 21; i++) {
+      size = 1U << i;
+      p = valloc(size - (2 * sizeof(void *)));
+      assert(p);
+      assert(((uintptr_t)p & (page_size - 1)) == 0);
+      free(p);
+      p = pvalloc(size - (2 * sizeof(void *)));
+      assert(p);
+      assert(((uintptr_t)p & (page_size - 1)) == 0);
+      assert(malloc_usable_size(p) >= round_up_to(size, page_size));
+      free(p);
+      p = valloc(size);
+      assert(p);
+      assert(((uintptr_t)p & (page_size - 1)) == 0);
+      free(p);
+      p = pvalloc(size);
+      assert(p);
+      assert(((uintptr_t)p & (page_size - 1)) == 0);
+      assert(malloc_usable_size(p) >= round_up_to(size, page_size));
+      free(p);
+    }
+  }
+  if (!strcmp(argv[1], "invalid")) {
+    // Size passed to pvalloc overflows when rounded up.
+    p = pvalloc((size_t)-1);
+    assert(!p);
+    assert(errno == ENOMEM);
+    errno = 0;
+    p = pvalloc((size_t)-page_size);
+    assert(!p);
+    assert(errno == ENOMEM);
+  }
+  return 0;
+}