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Issue 693943003: Update from https://crrev.com/302630 (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 6 years, 1 month ago
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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #include "sandbox/linux/seccomp-bpf/codegen.h" 5 #include "sandbox/linux/seccomp-bpf/codegen.h"
6 6
7 #include <errno.h>
8 #include <linux/filter.h> 7 #include <linux/filter.h>
9 8
10 #include <set> 9 #include <set>
11 #include <string> 10 #include <string>
12 #include <vector> 11 #include <vector>
13 12
14 #include "sandbox/linux/seccomp-bpf/basicblock.h" 13 #include "sandbox/linux/seccomp-bpf/basicblock.h"
15 #include "sandbox/linux/seccomp-bpf/errorcode.h" 14 #include "sandbox/linux/seccomp-bpf/errorcode.h"
16 #include "sandbox/linux/seccomp-bpf/instruction.h" 15 #include "sandbox/linux/seccomp-bpf/instruction.h"
17 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h" 16 #include "testing/gtest/include/gtest/gtest.h"
18 #include "sandbox/linux/tests/unit_tests.h"
19 17
20 namespace sandbox { 18 namespace sandbox {
21 19
22 // We want to access some of the private methods in the code generator. We 20 // We want to access some of the private methods in the code generator. We
23 // do so by defining a "friend" that makes these methods public for us. 21 // do so by defining a "friend" that makes these methods public for us.
24 class CodeGenUnittestHelper : public CodeGen { 22 class CodeGenUnittestHelper : public CodeGen {
25 public: 23 public:
26 void FindBranchTargets(const Instruction& instructions, 24 using CodeGen::CutGraphIntoBasicBlocks;
27 BranchTargets* branch_targets) { 25 using CodeGen::FindBranchTargets;
28 CodeGen::FindBranchTargets(instructions, branch_targets); 26 using CodeGen::MergeTails;
27 };
28
29 namespace {
30
31 enum {
32 NO_FLAGS = 0x0000,
33 HAS_MERGEABLE_TAILS = 0x0001,
34 };
35
36 using ProgramTestFunc = void (*)(CodeGenUnittestHelper* gen,
37 Instruction* head,
38 int flags);
39
40 class ProgramTest : public ::testing::TestWithParam<ProgramTestFunc> {
41 protected:
42 ProgramTest() : gen_() {}
43
44 // RunTest runs the test function argument. It should be called at
45 // the end of each program test case.
46 void RunTest(Instruction* head, int flags) { GetParam()(&gen_, head, flags); }
47
48 Instruction* MakeInstruction(uint16_t code,
49 uint32_t k,
50 Instruction* next = nullptr) {
51 Instruction* ret = gen_.MakeInstruction(code, k, next);
52 EXPECT_NE(nullptr, ret);
53 EXPECT_EQ(code, ret->code);
54 EXPECT_EQ(k, ret->k);
55 if (code == BPF_JMP + BPF_JA) {
56 // Annoying inconsistency.
57 EXPECT_EQ(nullptr, ret->next);
58 EXPECT_EQ(next, ret->jt_ptr);
59 } else {
60 EXPECT_EQ(next, ret->next);
61 EXPECT_EQ(nullptr, ret->jt_ptr);
62 }
63 EXPECT_EQ(nullptr, ret->jf_ptr);
64 return ret;
29 } 65 }
30 66
31 BasicBlock* CutGraphIntoBasicBlocks(Instruction* insns, 67 Instruction* MakeInstruction(uint16_t code,
32 const BranchTargets& branch_targets, 68 uint32_t k,
33 TargetsToBlocks* blocks) { 69 Instruction* jt,
34 return CodeGen::CutGraphIntoBasicBlocks(insns, branch_targets, blocks); 70 Instruction* jf) {
71 Instruction* ret = gen_.MakeInstruction(code, k, jt, jf);
72 EXPECT_NE(nullptr, ret);
73 EXPECT_EQ(code, ret->code);
74 EXPECT_EQ(k, ret->k);
75 EXPECT_EQ(nullptr, ret->next);
76 EXPECT_EQ(jt, ret->jt_ptr);
77 EXPECT_EQ(jf, ret->jf_ptr);
78 return ret;
35 } 79 }
36 80
37 void MergeTails(TargetsToBlocks* blocks) { CodeGen::MergeTails(blocks); } 81 private:
82 CodeGenUnittestHelper gen_;
38 }; 83 };
39 84
40 enum { NO_FLAGS = 0x0000, HAS_MERGEABLE_TAILS = 0x0001, }; 85 TEST_P(ProgramTest, OneInstruction) {
41
42 Instruction* SampleProgramOneInstruction(CodeGen* codegen, int* flags) {
43 // Create the most basic valid BPF program: 86 // Create the most basic valid BPF program:
44 // RET 0 87 // RET 0
45 *flags = NO_FLAGS; 88 Instruction* head = MakeInstruction(BPF_RET + BPF_K, 0);
46 return codegen->MakeInstruction(BPF_RET + BPF_K, 0); 89 RunTest(head, NO_FLAGS);
47 } 90 }
48 91
49 Instruction* SampleProgramSimpleBranch(CodeGen* codegen, int* flags) { 92 TEST_P(ProgramTest, SimpleBranch) {
50 // Create a program with a single branch: 93 // Create a program with a single branch:
51 // JUMP if eq 42 then $0 else $1 94 // JUMP if eq 42 then $0 else $1
52 // 0: RET 1 95 // 0: RET 1
53 // 1: RET 0 96 // 1: RET 0
54 *flags = NO_FLAGS; 97 Instruction* head = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K,
55 return codegen->MakeInstruction( 98 42,
56 BPF_JMP + BPF_JEQ + BPF_K, 99 MakeInstruction(BPF_RET + BPF_K, 1),
57 42, 100 MakeInstruction(BPF_RET + BPF_K, 0));
58 codegen->MakeInstruction(BPF_RET + BPF_K, 1), 101 RunTest(head, NO_FLAGS);
59 codegen->MakeInstruction(BPF_RET + BPF_K, 0));
60 } 102 }
61 103
62 Instruction* SampleProgramAtypicalBranch(CodeGen* codegen, int* flags) { 104 TEST_P(ProgramTest, AtypicalBranch) {
63 // Create a program with a single branch: 105 // Create a program with a single branch:
64 // JUMP if eq 42 then $0 else $0 106 // JUMP if eq 42 then $0 else $0
65 // 0: RET 0 107 // 0: RET 0
66 108
109 Instruction* ret = MakeInstruction(BPF_RET + BPF_K, 0);
110 Instruction* head = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, ret, ret);
111
67 // N.B.: As the instructions in both sides of the branch are already 112 // N.B.: As the instructions in both sides of the branch are already
68 // the same object, we do not actually have any "mergeable" branches. 113 // the same object, we do not actually have any "mergeable" branches.
69 // This needs to be reflected in our choice of "flags". 114 // This needs to be reflected in our choice of "flags".
70 *flags = NO_FLAGS; 115 RunTest(head, NO_FLAGS);
71
72 Instruction* ret = codegen->MakeInstruction(
73 BPF_RET + BPF_K, 0);
74 return codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, ret, ret);
75 } 116 }
76 117
77 Instruction* SampleProgramComplex(CodeGen* codegen, int* flags) { 118 TEST_P(ProgramTest, Complex) {
78 // Creates a basic BPF program that we'll use to test some of the code: 119 // Creates a basic BPF program that we'll use to test some of the code:
79 // JUMP if eq 42 the $0 else $1 (insn6) 120 // JUMP if eq 42 the $0 else $1 (insn6)
80 // 0: LD 23 (insn5) 121 // 0: LD 23 (insn5)
81 // 1: JUMP if eq 42 then $2 else $4 (insn4) 122 // 1: JUMP if eq 42 then $2 else $4 (insn4)
82 // 2: JUMP to $3 (insn2) 123 // 2: JUMP to $3 (insn2)
83 // 3: LD 42 (insn1) 124 // 3: LD 42 (insn1)
84 // RET 42 (insn0) 125 // RET 42 (insn0)
85 // 4: LD 42 (insn3) 126 // 4: LD 42 (insn3)
86 // RET 42 (insn3+) 127 // RET 42 (insn3+)
87 *flags = HAS_MERGEABLE_TAILS; 128 Instruction* insn0 = MakeInstruction(BPF_RET + BPF_K, 42);
88 129 Instruction* insn1 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 42, insn0);
89 Instruction* insn0 = codegen->MakeInstruction(BPF_RET + BPF_K, 42); 130 Instruction* insn2 = MakeInstruction(BPF_JMP + BPF_JA, 0, insn1);
90 SANDBOX_ASSERT(insn0);
91 SANDBOX_ASSERT(insn0->code == BPF_RET + BPF_K);
92 SANDBOX_ASSERT(insn0->next == NULL);
93
94 Instruction* insn1 =
95 codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 42, insn0);
96 SANDBOX_ASSERT(insn1);
97 SANDBOX_ASSERT(insn1->code == BPF_LD + BPF_W + BPF_ABS);
98 SANDBOX_ASSERT(insn1->k == 42);
99 SANDBOX_ASSERT(insn1->next == insn0);
100
101 Instruction* insn2 = codegen->MakeInstruction(BPF_JMP + BPF_JA, 0, insn1);
102 SANDBOX_ASSERT(insn2);
103 SANDBOX_ASSERT(insn2->code == BPF_JMP + BPF_JA);
104 SANDBOX_ASSERT(insn2->jt_ptr == insn1);
105 131
106 // We explicitly duplicate instructions so that MergeTails() can coalesce 132 // We explicitly duplicate instructions so that MergeTails() can coalesce
107 // them later. 133 // them later.
108 Instruction* insn3 = codegen->MakeInstruction( 134 Instruction* insn3 = MakeInstruction(
109 BPF_LD + BPF_W + BPF_ABS, 135 BPF_LD + BPF_W + BPF_ABS, 42, MakeInstruction(BPF_RET + BPF_K, 42));
110 42,
111 codegen->MakeInstruction(BPF_RET + BPF_K, 42));
112 136
113 Instruction* insn4 = 137 Instruction* insn4 =
114 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, insn2, insn3); 138 MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, insn2, insn3);
115 SANDBOX_ASSERT(insn4); 139 Instruction* insn5 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 23, insn4);
116 SANDBOX_ASSERT(insn4->code == BPF_JMP + BPF_JEQ + BPF_K);
117 SANDBOX_ASSERT(insn4->k == 42);
118 SANDBOX_ASSERT(insn4->jt_ptr == insn2);
119 SANDBOX_ASSERT(insn4->jf_ptr == insn3);
120
121 Instruction* insn5 =
122 codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 23, insn4);
123 SANDBOX_ASSERT(insn5);
124 SANDBOX_ASSERT(insn5->code == BPF_LD + BPF_W + BPF_ABS);
125 SANDBOX_ASSERT(insn5->k == 23);
126 SANDBOX_ASSERT(insn5->next == insn4);
127 140
128 // Force a basic block that ends in neither a jump instruction nor a return 141 // Force a basic block that ends in neither a jump instruction nor a return
129 // instruction. It only contains "insn5". This exercises one of the less 142 // instruction. It only contains "insn5". This exercises one of the less
130 // common code paths in the topo-sort algorithm. 143 // common code paths in the topo-sort algorithm.
131 // This also gives us a diamond-shaped pattern in our graph, which stresses 144 // This also gives us a diamond-shaped pattern in our graph, which stresses
132 // another aspect of the topo-sort algorithm (namely, the ability to 145 // another aspect of the topo-sort algorithm (namely, the ability to
133 // correctly count the incoming branches for subtrees that are not disjunct). 146 // correctly count the incoming branches for subtrees that are not disjunct).
134 Instruction* insn6 = 147 Instruction* insn6 =
135 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, insn5, insn4); 148 MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, insn5, insn4);
136 149
137 return insn6; 150 RunTest(insn6, HAS_MERGEABLE_TAILS);
138 } 151 }
139 152
140 Instruction* SampleProgramConfusingTails(CodeGen* codegen, int* flags) { 153 TEST_P(ProgramTest, ConfusingTails) {
141 // This simple program demonstrates https://crbug.com/351103/ 154 // This simple program demonstrates https://crbug.com/351103/
142 // The two "LOAD 0" instructions are blocks of their own. MergeTails() could 155 // The two "LOAD 0" instructions are blocks of their own. MergeTails() could
143 // be tempted to merge them since they are the same. However, they are 156 // be tempted to merge them since they are the same. However, they are
144 // not mergeable because they fall-through to non semantically equivalent 157 // not mergeable because they fall-through to non semantically equivalent
145 // blocks. 158 // blocks.
146 // Without the fix for this bug, this program should trigger the check in 159 // Without the fix for this bug, this program should trigger the check in
147 // CompileAndCompare: the serialized graphs from the program and its compiled 160 // CompileAndCompare: the serialized graphs from the program and its compiled
148 // version will differ. 161 // version will differ.
149 // 162 //
150 // 0) LOAD 1 // ??? 163 // 0) LOAD 1 // ???
151 // 1) if A == 0x1; then JMP 2 else JMP 3 164 // 1) if A == 0x1; then JMP 2 else JMP 3
152 // 2) LOAD 0 // System call number 165 // 2) LOAD 0 // System call number
153 // 3) if A == 0x2; then JMP 4 else JMP 5 166 // 3) if A == 0x2; then JMP 4 else JMP 5
154 // 4) LOAD 0 // System call number 167 // 4) LOAD 0 // System call number
155 // 5) if A == 0x1; then JMP 6 else JMP 7 168 // 5) if A == 0x1; then JMP 6 else JMP 7
156 // 6) RET 0 169 // 6) RET 0
157 // 7) RET 1 170 // 7) RET 1
158 *flags = NO_FLAGS;
159 171
160 Instruction* i7 = codegen->MakeInstruction(BPF_RET + BPF_K, 1); 172 Instruction* i7 = MakeInstruction(BPF_RET + BPF_K, 1);
161 Instruction* i6 = codegen->MakeInstruction(BPF_RET + BPF_K, 0); 173 Instruction* i6 = MakeInstruction(BPF_RET + BPF_K, 0);
162 Instruction* i5 = 174 Instruction* i5 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i6, i7);
163 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i6, i7); 175 Instruction* i4 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i5);
164 Instruction* i4 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i5); 176 Instruction* i3 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5);
165 Instruction* i3 = 177 Instruction* i2 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i3);
166 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5); 178 Instruction* i1 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
167 Instruction* i2 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i3); 179 Instruction* i0 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
168 Instruction* i1 =
169 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
170 Instruction* i0 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
171 180
172 return i0; 181 RunTest(i0, NO_FLAGS);
173 } 182 }
174 183
175 Instruction* SampleProgramConfusingTailsBasic(CodeGen* codegen, int* flags) { 184 TEST_P(ProgramTest, ConfusingTailsBasic) {
176 // Without the fix for https://crbug.com/351103/, (see 185 // Without the fix for https://crbug.com/351103/, (see
177 // SampleProgramConfusingTails()), this would generate a cyclic graph and 186 // SampleProgramConfusingTails()), this would generate a cyclic graph and
178 // crash as the two "LOAD 0" instructions would get merged. 187 // crash as the two "LOAD 0" instructions would get merged.
179 // 188 //
180 // 0) LOAD 1 // ??? 189 // 0) LOAD 1 // ???
181 // 1) if A == 0x1; then JMP 2 else JMP 3 190 // 1) if A == 0x1; then JMP 2 else JMP 3
182 // 2) LOAD 0 // System call number 191 // 2) LOAD 0 // System call number
183 // 3) if A == 0x2; then JMP 4 else JMP 5 192 // 3) if A == 0x2; then JMP 4 else JMP 5
184 // 4) LOAD 0 // System call number 193 // 4) LOAD 0 // System call number
185 // 5) RET 1 194 // 5) RET 1
186 *flags = NO_FLAGS;
187 195
188 Instruction* i5 = codegen->MakeInstruction(BPF_RET + BPF_K, 1); 196 Instruction* i5 = MakeInstruction(BPF_RET + BPF_K, 1);
189 Instruction* i4 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i5); 197 Instruction* i4 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i5);
190 Instruction* i3 = 198 Instruction* i3 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5);
191 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5); 199 Instruction* i2 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i3);
192 Instruction* i2 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0, i3); 200 Instruction* i1 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
193 Instruction* i1 = 201 Instruction* i0 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
194 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
195 Instruction* i0 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
196 202
197 return i0; 203 RunTest(i0, NO_FLAGS);
198 } 204 }
199 205
200 Instruction* SampleProgramConfusingTailsMergeable(CodeGen* codegen, 206 TEST_P(ProgramTest, ConfusingTailsMergeable) {
201 int* flags) {
202 // This is similar to SampleProgramConfusingTails(), except that 207 // This is similar to SampleProgramConfusingTails(), except that
203 // instructions 2 and 4 are now RET instructions. 208 // instructions 2 and 4 are now RET instructions.
204 // In PointerCompare(), this exercises the path where two blocks are of the 209 // In PointerCompare(), this exercises the path where two blocks are of the
205 // same length and identical and the last instruction is a JMP or RET, so the 210 // same length and identical and the last instruction is a JMP or RET, so the
206 // following blocks don't need to be looked at and the blocks are mergeable. 211 // following blocks don't need to be looked at and the blocks are mergeable.
207 // 212 //
208 // 0) LOAD 1 // ??? 213 // 0) LOAD 1 // ???
209 // 1) if A == 0x1; then JMP 2 else JMP 3 214 // 1) if A == 0x1; then JMP 2 else JMP 3
210 // 2) RET 42 215 // 2) RET 42
211 // 3) if A == 0x2; then JMP 4 else JMP 5 216 // 3) if A == 0x2; then JMP 4 else JMP 5
212 // 4) RET 42 217 // 4) RET 42
213 // 5) if A == 0x1; then JMP 6 else JMP 7 218 // 5) if A == 0x1; then JMP 6 else JMP 7
214 // 6) RET 0 219 // 6) RET 0
215 // 7) RET 1 220 // 7) RET 1
216 *flags = HAS_MERGEABLE_TAILS;
217 221
218 Instruction* i7 = codegen->MakeInstruction(BPF_RET + BPF_K, 1); 222 Instruction* i7 = MakeInstruction(BPF_RET + BPF_K, 1);
219 Instruction* i6 = codegen->MakeInstruction(BPF_RET + BPF_K, 0); 223 Instruction* i6 = MakeInstruction(BPF_RET + BPF_K, 0);
220 Instruction* i5 = 224 Instruction* i5 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i6, i7);
221 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i6, i7); 225 Instruction* i4 = MakeInstruction(BPF_RET + BPF_K, 42);
222 Instruction* i4 = codegen->MakeInstruction(BPF_RET + BPF_K, 42); 226 Instruction* i3 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5);
223 Instruction* i3 = 227 Instruction* i2 = MakeInstruction(BPF_RET + BPF_K, 42);
224 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 2, i4, i5); 228 Instruction* i1 = MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
225 Instruction* i2 = codegen->MakeInstruction(BPF_RET + BPF_K, 42); 229 Instruction* i0 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
226 Instruction* i1 =
227 codegen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 1, i2, i3);
228 Instruction* i0 = codegen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 1, i1);
229 230
230 return i0; 231 RunTest(i0, HAS_MERGEABLE_TAILS);
231 }
232 void ForAllPrograms(void (*test)(CodeGenUnittestHelper*, Instruction*, int)) {
233 Instruction* (*function_table[])(CodeGen* codegen, int* flags) = {
234 SampleProgramOneInstruction,
235 SampleProgramSimpleBranch,
236 SampleProgramAtypicalBranch,
237 SampleProgramComplex,
238 SampleProgramConfusingTails,
239 SampleProgramConfusingTailsBasic,
240 SampleProgramConfusingTailsMergeable,
241 };
242
243 for (size_t i = 0; i < arraysize(function_table); ++i) {
244 CodeGenUnittestHelper codegen;
245 int flags = NO_FLAGS;
246 Instruction *prg = function_table[i](&codegen, &flags);
247 test(&codegen, prg, flags);
248 }
249 } 232 }
250 233
251 void MakeInstruction(CodeGenUnittestHelper* codegen, 234 void MakeInstruction(CodeGenUnittestHelper* codegen,
252 Instruction* program, int) { 235 Instruction* program, int) {
253 // Nothing to do here 236 // Nothing to do here
254 } 237 }
255 238
256 SANDBOX_TEST(CodeGen, MakeInstruction) {
257 ForAllPrograms(MakeInstruction);
258 }
259
260 void FindBranchTargets(CodeGenUnittestHelper* codegen, Instruction* prg, int) { 239 void FindBranchTargets(CodeGenUnittestHelper* codegen, Instruction* prg, int) {
261 BranchTargets branch_targets; 240 BranchTargets branch_targets;
262 codegen->FindBranchTargets(*prg, &branch_targets); 241 codegen->FindBranchTargets(*prg, &branch_targets);
263 242
264 // Verifying the general properties that should be true for every 243 // Verifying the general properties that should be true for every
265 // well-formed BPF program. 244 // well-formed BPF program.
266 // Perform a depth-first traversal of the BPF program an verify that all 245 // Perform a depth-first traversal of the BPF program an verify that all
267 // targets of BPF_JMP instructions are represented in the "branch_targets". 246 // targets of BPF_JMP instructions are represented in the "branch_targets".
268 // At the same time, compute a set of both the branch targets and all the 247 // At the same time, compute a set of both the branch targets and all the
269 // instructions in the program. 248 // instructions in the program.
270 std::vector<Instruction*> stack; 249 std::vector<Instruction*> stack;
271 std::set<Instruction*> all_instructions; 250 std::set<Instruction*> all_instructions;
272 std::set<Instruction*> target_instructions; 251 std::set<Instruction*> target_instructions;
273 BranchTargets::const_iterator end = branch_targets.end(); 252 BranchTargets::const_iterator end = branch_targets.end();
274 for (Instruction* insn = prg;;) { 253 for (Instruction* insn = prg;;) {
275 all_instructions.insert(insn); 254 all_instructions.insert(insn);
276 if (BPF_CLASS(insn->code) == BPF_JMP) { 255 if (BPF_CLASS(insn->code) == BPF_JMP) {
277 target_instructions.insert(insn->jt_ptr); 256 target_instructions.insert(insn->jt_ptr);
278 SANDBOX_ASSERT(insn->jt_ptr != NULL); 257 ASSERT_TRUE(insn->jt_ptr != NULL);
279 SANDBOX_ASSERT(branch_targets.find(insn->jt_ptr) != end); 258 ASSERT_TRUE(branch_targets.find(insn->jt_ptr) != end);
280 if (BPF_OP(insn->code) != BPF_JA) { 259 if (BPF_OP(insn->code) != BPF_JA) {
281 target_instructions.insert(insn->jf_ptr); 260 target_instructions.insert(insn->jf_ptr);
282 SANDBOX_ASSERT(insn->jf_ptr != NULL); 261 ASSERT_TRUE(insn->jf_ptr != NULL);
283 SANDBOX_ASSERT(branch_targets.find(insn->jf_ptr) != end); 262 ASSERT_TRUE(branch_targets.find(insn->jf_ptr) != end);
284 stack.push_back(insn->jf_ptr); 263 stack.push_back(insn->jf_ptr);
285 } 264 }
286 insn = insn->jt_ptr; 265 insn = insn->jt_ptr;
287 } else if (BPF_CLASS(insn->code) == BPF_RET) { 266 } else if (BPF_CLASS(insn->code) == BPF_RET) {
288 SANDBOX_ASSERT(insn->next == NULL); 267 ASSERT_TRUE(insn->next == NULL);
289 if (stack.empty()) { 268 if (stack.empty()) {
290 break; 269 break;
291 } 270 }
292 insn = stack.back(); 271 insn = stack.back();
293 stack.pop_back(); 272 stack.pop_back();
294 } else { 273 } else {
295 SANDBOX_ASSERT(insn->next != NULL); 274 ASSERT_TRUE(insn->next != NULL);
296 insn = insn->next; 275 insn = insn->next;
297 } 276 }
298 } 277 }
299 SANDBOX_ASSERT(target_instructions.size() == branch_targets.size()); 278 ASSERT_TRUE(target_instructions.size() == branch_targets.size());
300 279
301 // We can now subtract the set of the branch targets from the set of all 280 // We can now subtract the set of the branch targets from the set of all
302 // instructions. This gives us a set with the instructions that nobody 281 // instructions. This gives us a set with the instructions that nobody
303 // ever jumps to. Verify that they are no included in the 282 // ever jumps to. Verify that they are no included in the
304 // "branch_targets" that FindBranchTargets() computed for us. 283 // "branch_targets" that FindBranchTargets() computed for us.
305 Instructions non_target_instructions(all_instructions.size() - 284 Instructions non_target_instructions(all_instructions.size() -
306 target_instructions.size()); 285 target_instructions.size());
307 set_difference(all_instructions.begin(), 286 set_difference(all_instructions.begin(),
308 all_instructions.end(), 287 all_instructions.end(),
309 target_instructions.begin(), 288 target_instructions.begin(),
310 target_instructions.end(), 289 target_instructions.end(),
311 non_target_instructions.begin()); 290 non_target_instructions.begin());
312 for (Instructions::const_iterator iter = non_target_instructions.begin(); 291 for (Instructions::const_iterator iter = non_target_instructions.begin();
313 iter != non_target_instructions.end(); 292 iter != non_target_instructions.end();
314 ++iter) { 293 ++iter) {
315 SANDBOX_ASSERT(branch_targets.find(*iter) == end); 294 ASSERT_TRUE(branch_targets.find(*iter) == end);
316 } 295 }
317 } 296 }
318 297
319 SANDBOX_TEST(CodeGen, FindBranchTargets) { ForAllPrograms(FindBranchTargets); }
320
321 void CutGraphIntoBasicBlocks(CodeGenUnittestHelper* codegen, 298 void CutGraphIntoBasicBlocks(CodeGenUnittestHelper* codegen,
322 Instruction* prg, 299 Instruction* prg,
323 int) { 300 int) {
324 BranchTargets branch_targets; 301 BranchTargets branch_targets;
325 codegen->FindBranchTargets(*prg, &branch_targets); 302 codegen->FindBranchTargets(*prg, &branch_targets);
326 TargetsToBlocks all_blocks; 303 TargetsToBlocks all_blocks;
327 BasicBlock* first_block = 304 BasicBlock* first_block =
328 codegen->CutGraphIntoBasicBlocks(prg, branch_targets, &all_blocks); 305 codegen->CutGraphIntoBasicBlocks(prg, branch_targets, &all_blocks);
329 SANDBOX_ASSERT(first_block != NULL); 306 ASSERT_TRUE(first_block != NULL);
330 SANDBOX_ASSERT(first_block->instructions.size() > 0); 307 ASSERT_TRUE(first_block->instructions.size() > 0);
331 Instruction* first_insn = first_block->instructions[0]; 308 Instruction* first_insn = first_block->instructions[0];
332 309
333 // Basic blocks are supposed to start with a branch target and end with 310 // Basic blocks are supposed to start with a branch target and end with
334 // either a jump or a return instruction. It can also end, if the next 311 // either a jump or a return instruction. It can also end, if the next
335 // instruction forms the beginning of a new basic block. There should be 312 // instruction forms the beginning of a new basic block. There should be
336 // no other jumps or return instructions in the middle of a basic block. 313 // no other jumps or return instructions in the middle of a basic block.
337 for (TargetsToBlocks::const_iterator bb_iter = all_blocks.begin(); 314 for (TargetsToBlocks::const_iterator bb_iter = all_blocks.begin();
338 bb_iter != all_blocks.end(); 315 bb_iter != all_blocks.end();
339 ++bb_iter) { 316 ++bb_iter) {
340 BasicBlock* bb = bb_iter->second; 317 BasicBlock* bb = bb_iter->second;
341 SANDBOX_ASSERT(bb != NULL); 318 ASSERT_TRUE(bb != NULL);
342 SANDBOX_ASSERT(bb->instructions.size() > 0); 319 ASSERT_TRUE(bb->instructions.size() > 0);
343 Instruction* insn = bb->instructions[0]; 320 Instruction* insn = bb->instructions[0];
344 SANDBOX_ASSERT(insn == first_insn || 321 ASSERT_TRUE(insn == first_insn ||
345 branch_targets.find(insn) != branch_targets.end()); 322 branch_targets.find(insn) != branch_targets.end());
346 for (Instructions::const_iterator insn_iter = bb->instructions.begin();;) { 323 for (Instructions::const_iterator insn_iter = bb->instructions.begin();;) {
347 insn = *insn_iter; 324 insn = *insn_iter;
348 if (++insn_iter != bb->instructions.end()) { 325 if (++insn_iter != bb->instructions.end()) {
349 SANDBOX_ASSERT(BPF_CLASS(insn->code) != BPF_JMP); 326 ASSERT_TRUE(BPF_CLASS(insn->code) != BPF_JMP);
350 SANDBOX_ASSERT(BPF_CLASS(insn->code) != BPF_RET); 327 ASSERT_TRUE(BPF_CLASS(insn->code) != BPF_RET);
351 } else { 328 } else {
352 SANDBOX_ASSERT(BPF_CLASS(insn->code) == BPF_JMP || 329 ASSERT_TRUE(BPF_CLASS(insn->code) == BPF_JMP ||
353 BPF_CLASS(insn->code) == BPF_RET || 330 BPF_CLASS(insn->code) == BPF_RET ||
354 branch_targets.find(insn->next) != branch_targets.end()); 331 branch_targets.find(insn->next) != branch_targets.end());
355 break; 332 break;
356 } 333 }
357 SANDBOX_ASSERT(branch_targets.find(*insn_iter) == branch_targets.end()); 334 ASSERT_TRUE(branch_targets.find(*insn_iter) == branch_targets.end());
358 } 335 }
359 } 336 }
360 } 337 }
361 338
362 SANDBOX_TEST(CodeGen, CutGraphIntoBasicBlocks) {
363 ForAllPrograms(CutGraphIntoBasicBlocks);
364 }
365
366 void MergeTails(CodeGenUnittestHelper* codegen, Instruction* prg, int flags) { 339 void MergeTails(CodeGenUnittestHelper* codegen, Instruction* prg, int flags) {
367 BranchTargets branch_targets; 340 BranchTargets branch_targets;
368 codegen->FindBranchTargets(*prg, &branch_targets); 341 codegen->FindBranchTargets(*prg, &branch_targets);
369 TargetsToBlocks all_blocks; 342 TargetsToBlocks all_blocks;
370 BasicBlock* first_block = 343 BasicBlock* first_block =
371 codegen->CutGraphIntoBasicBlocks(prg, branch_targets, &all_blocks); 344 codegen->CutGraphIntoBasicBlocks(prg, branch_targets, &all_blocks);
372 345
373 // The shape of our graph and thus the function of our program should 346 // The shape of our graph and thus the function of our program should
374 // still be unchanged after we run MergeTails(). We verify this by 347 // still be unchanged after we run MergeTails(). We verify this by
375 // serializing the graph and verifying that it is still the same. 348 // serializing the graph and verifying that it is still the same.
(...skipping 52 matching lines...) Expand 10 before | Expand all | Expand 10 after
428 bb = all_blocks[insn->next]; 401 bb = all_blocks[insn->next];
429 } 402 }
430 } 403 }
431 404
432 // Our loop runs exactly two times. 405 // Our loop runs exactly two times.
433 if (++i > 1) { 406 if (++i > 1) {
434 break; 407 break;
435 } 408 }
436 codegen->MergeTails(&all_blocks); 409 codegen->MergeTails(&all_blocks);
437 } 410 }
438 SANDBOX_ASSERT(graph[0] == graph[1]); 411 ASSERT_TRUE(graph[0] == graph[1]);
439 if (flags & HAS_MERGEABLE_TAILS) { 412 if (flags & HAS_MERGEABLE_TAILS) {
440 SANDBOX_ASSERT(edges[0] != edges[1]); 413 ASSERT_TRUE(edges[0] != edges[1]);
441 } else { 414 } else {
442 SANDBOX_ASSERT(edges[0] == edges[1]); 415 ASSERT_TRUE(edges[0] == edges[1]);
443 } 416 }
444 } 417 }
445 418
446 SANDBOX_TEST(CodeGen, MergeTails) {
447 ForAllPrograms(MergeTails);
448 }
449
450 void CompileAndCompare(CodeGenUnittestHelper* codegen, Instruction* prg, int) { 419 void CompileAndCompare(CodeGenUnittestHelper* codegen, Instruction* prg, int) {
451 // TopoSortBasicBlocks() has internal checks that cause it to fail, if it 420 // TopoSortBasicBlocks() has internal checks that cause it to fail, if it
452 // detects a problem. Typically, if anything goes wrong, this looks to the 421 // detects a problem. Typically, if anything goes wrong, this looks to the
453 // TopoSort algorithm as if there had been cycles in the input data. 422 // TopoSort algorithm as if there had been cycles in the input data.
454 // This provides a pretty good unittest. 423 // This provides a pretty good unittest.
455 // We hand-crafted the program returned by SampleProgram() to exercise 424 // We hand-crafted the program returned by SampleProgram() to exercise
456 // several of the more interesting code-paths. See comments in 425 // several of the more interesting code-paths. See comments in
457 // SampleProgram() for details. 426 // SampleProgram() for details.
458 // In addition to relying on the internal consistency checks in the compiler, 427 // In addition to relying on the internal consistency checks in the compiler,
459 // we also serialize the graph and the resulting BPF program and compare 428 // we also serialize the graph and the resulting BPF program and compare
(...skipping 32 matching lines...) Expand 10 before | Expand all | Expand 10 after
492 } 461 }
493 462
494 // Compile the program 463 // Compile the program
495 CodeGen::Program bpf; 464 CodeGen::Program bpf;
496 codegen->Compile(prg, &bpf); 465 codegen->Compile(prg, &bpf);
497 466
498 // Serialize the resulting BPF instructions. 467 // Serialize the resulting BPF instructions.
499 std::string assembly; 468 std::string assembly;
500 std::vector<int> assembly_stack; 469 std::vector<int> assembly_stack;
501 for (int idx = 0; idx >= 0;) { 470 for (int idx = 0; idx >= 0;) {
502 SANDBOX_ASSERT(idx < (int)bpf.size()); 471 ASSERT_TRUE(idx < (int)bpf.size());
503 struct sock_filter& insn = bpf[idx]; 472 struct sock_filter& insn = bpf[idx];
504 if (BPF_CLASS(insn.code) == BPF_JMP) { 473 if (BPF_CLASS(insn.code) == BPF_JMP) {
505 if (BPF_OP(insn.code) == BPF_JA) { 474 if (BPF_OP(insn.code) == BPF_JA) {
506 // Do not serialize BPF_JA instructions (see above). 475 // Do not serialize BPF_JA instructions (see above).
507 idx += insn.k + 1; 476 idx += insn.k + 1;
508 continue; 477 continue;
509 } else { 478 } else {
510 assembly_stack.push_back(idx + insn.jf + 1); 479 assembly_stack.push_back(idx + insn.jf + 1);
511 idx += insn.jt + 1; 480 idx += insn.jt + 1;
512 } 481 }
513 } else if (BPF_CLASS(insn.code) == BPF_RET) { 482 } else if (BPF_CLASS(insn.code) == BPF_RET) {
514 if (assembly_stack.empty()) { 483 if (assembly_stack.empty()) {
515 idx = -1; 484 idx = -1;
516 } else { 485 } else {
517 idx = assembly_stack.back(); 486 idx = assembly_stack.back();
518 assembly_stack.pop_back(); 487 assembly_stack.pop_back();
519 } 488 }
520 } else { 489 } else {
521 ++idx; 490 ++idx;
522 } 491 }
523 // Serialize the same information that we serialized before compilation. 492 // Serialize the same information that we serialized before compilation.
524 assembly.append(reinterpret_cast<char*>(&insn.code), sizeof(insn.code)); 493 assembly.append(reinterpret_cast<char*>(&insn.code), sizeof(insn.code));
525 assembly.append(reinterpret_cast<char*>(&insn.k), sizeof(insn.k)); 494 assembly.append(reinterpret_cast<char*>(&insn.k), sizeof(insn.k));
526 } 495 }
527 SANDBOX_ASSERT(source == assembly); 496 ASSERT_TRUE(source == assembly);
528 } 497 }
529 498
530 SANDBOX_TEST(CodeGen, All) { 499 const ProgramTestFunc kProgramTestFuncs[] = {
531 ForAllPrograms(CompileAndCompare); 500 MakeInstruction,
532 } 501 FindBranchTargets,
502 CutGraphIntoBasicBlocks,
503 MergeTails,
504 CompileAndCompare,
505 };
506
507 INSTANTIATE_TEST_CASE_P(CodeGen,
508 ProgramTest,
509 ::testing::ValuesIn(kProgramTestFuncs));
510
511 } // namespace
533 512
534 } // namespace sandbox 513 } // namespace sandbox
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