1 //===-- slot_reuse.cpp ------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "gwp_asan/tests/harness.h"
10 
11 #include <set>
12 
13 void singleByteGoodAllocDealloc(gwp_asan::GuardedPoolAllocator *GPA) {
14   void *Ptr = GPA->allocate(1);
15   EXPECT_NE(nullptr, Ptr);
16   EXPECT_TRUE(GPA->pointerIsMine(Ptr));
17   EXPECT_EQ(1u, GPA->getSize(Ptr));
18   GPA->deallocate(Ptr);
19 }
20 
21 TEST_F(CustomGuardedPoolAllocator, EnsureReuseOfQuarantine1) {
22   InitNumSlots(1);
23   for (unsigned i = 0; i < 128; ++i)
24     singleByteGoodAllocDealloc(&GPA);
25 }
26 
27 TEST_F(CustomGuardedPoolAllocator, EnsureReuseOfQuarantine2) {
28   InitNumSlots(2);
29   for (unsigned i = 0; i < 128; ++i)
30     singleByteGoodAllocDealloc(&GPA);
31 }
32 
33 TEST_F(CustomGuardedPoolAllocator, EnsureReuseOfQuarantine127) {
34   InitNumSlots(127);
35   for (unsigned i = 0; i < 128; ++i)
36     singleByteGoodAllocDealloc(&GPA);
37 }
38 
39 // This test ensures that our slots are not reused ahead of time. We increase
40 // the use-after-free detection by not reusing slots until all of them have been
41 // allocated. This is done by always using the slots from left-to-right in the
42 // pool before we used each slot once, at which point random selection takes
43 // over.
44 void runNoReuseBeforeNecessary(gwp_asan::GuardedPoolAllocator *GPA,
45                                unsigned PoolSize) {
46   std::set<void *> Ptrs;
47   for (unsigned i = 0; i < PoolSize; ++i) {
48     void *Ptr = GPA->allocate(1);
49 
50     EXPECT_TRUE(GPA->pointerIsMine(Ptr));
51     EXPECT_EQ(0u, Ptrs.count(Ptr));
52 
53     Ptrs.insert(Ptr);
54     GPA->deallocate(Ptr);
55   }
56 }
57 
58 TEST_F(CustomGuardedPoolAllocator, NoReuseBeforeNecessary2) {
59   constexpr unsigned kPoolSize = 2;
60   InitNumSlots(kPoolSize);
61   runNoReuseBeforeNecessary(&GPA, kPoolSize);
62 }
63 
64 TEST_F(CustomGuardedPoolAllocator, NoReuseBeforeNecessary128) {
65   constexpr unsigned kPoolSize = 128;
66   InitNumSlots(kPoolSize);
67   runNoReuseBeforeNecessary(&GPA, kPoolSize);
68 }
69 
70 TEST_F(CustomGuardedPoolAllocator, NoReuseBeforeNecessary129) {
71   constexpr unsigned kPoolSize = 129;
72   InitNumSlots(kPoolSize);
73   runNoReuseBeforeNecessary(&GPA, kPoolSize);
74 }
75