xref: /llvm-project/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp (revision 3a67b912386e70073efcb2225c6354b85048b1ae) 
1 // RUN: %clang_cc1 -std=c++20 -Wno-all -Wunsafe-buffer-usage \
2 // RUN:            -fsafe-buffer-usage-suggestions \
3 // RUN:            -fblocks -include %s -verify %s
4 
5 // RUN: %clang -x c++ -fsyntax-only -fblocks -include %s %s 2>&1 | FileCheck --allow-empty %s
6 // RUN: %clang_cc1 -std=c++11 -fblocks -include %s %s 2>&1 | FileCheck --allow-empty %s
7 // RUN: %clang_cc1 -std=c++20 -fblocks -include %s %s 2>&1 | FileCheck --allow-empty %s
8 // CHECK-NOT: [-Wunsafe-buffer-usage]
9 
10 #ifndef INCLUDED
11 #define INCLUDED
12 #pragma clang system_header
13 
14 // no spanification warnings for system headers
15 void foo(...);  // let arguments of `foo` to hold testing expressions
16 void testAsSystemHeader(char *p) {
17   ++p;
18 
19   auto ap1 = p;
20   auto ap2 = &p;
21 
22   foo(p[1],
23       ap1[1],
24       ap2[2][3]);
25 }
26 
27 #else
28 
29 void testIncrement(char *p) { // expected-warning{{'p' is an unsafe pointer used for buffer access}}
30   ++p; // expected-note{{used in pointer arithmetic here}}
31   p++; // expected-note{{used in pointer arithmetic here}}
32   --p; // expected-note{{used in pointer arithmetic here}}
33   p--; // expected-note{{used in pointer arithmetic here}}
34 }
35 
36 void * voidPtrCall(void);
37 char * charPtrCall(void);
38 
39 void testArraySubscripts(int *p, int **pp) { // expected-note{{change type of 'pp' to 'std::span' to preserve bounds information}}
40 // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
41 // expected-warning@-2{{'pp' is an unsafe pointer used for buffer access}}
42   foo(p[1],             // expected-note{{used in buffer access here}}
43       pp[1][1],         // expected-note{{used in buffer access here}}
44                         // expected-warning@-1{{unsafe buffer access}}
45       1[1[pp]],         // expected-note{{used in buffer access here}}
46                         // expected-warning@-1{{unsafe buffer access}}
47       1[pp][1]          // expected-note{{used in buffer access here}}
48                         // expected-warning@-1{{unsafe buffer access}}
49       );
50 
51   if (p[3]) {           // expected-note{{used in buffer access here}}
52     void * q = p;
53 
54     foo(((int*)q)[10]); // expected-warning{{unsafe buffer access}}
55   }
56 
57   foo(((int*)voidPtrCall())[3], // expected-warning{{unsafe buffer access}}
58       3[(int*)voidPtrCall()],   // expected-warning{{unsafe buffer access}}
59       charPtrCall()[3],         // expected-warning{{unsafe buffer access}}
60       3[charPtrCall()]          // expected-warning{{unsafe buffer access}}
61       );
62 
63     int a[10];          // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
64     int b[10][10];      // expected-warning{{'b' is an unsafe buffer that does not perform bounds checks}}
65 
66   foo(a[1], 1[a],   // expected-note2{{used in buffer access here}}
67       b[3][4],      // expected-warning{{unsafe buffer access}}
68                     // expected-note@-1{{used in buffer access here}}
69       4[b][3],      // expected-warning{{unsafe buffer access}}
70                     // expected-note@-1{{used in buffer access here}}
71       4[3[b]]);     // expected-warning{{unsafe buffer access}}
72                     // expected-note@-1{{used in buffer access here}}
73 
74   // Not to warn when index is zero
75   foo(p[0], pp[0][0], 0[0[pp]], 0[pp][0],
76       ((int*)voidPtrCall())[0],
77       0[(int*)voidPtrCall()],
78       charPtrCall()[0],
79       0[charPtrCall()]
80       );
81 }
82 
83 void testArraySubscriptsWithAuto() {
84   int a[10];
85   // We do not fix a declaration if the type is `auto`. Because the actual type may change later.
86   auto ap1 = a;   // expected-warning{{'ap1' is an unsafe pointer used for buffer access}}
87   foo(ap1[1]);    // expected-note{{used in buffer access here}}
88 
89   // In case the type is `auto *`, we know it must be a pointer. We can fix it.
90   auto * ap2 = a; // expected-warning{{'ap2' is an unsafe pointer used for buffer access}} \
91                      expected-note{{change type of 'ap2' to 'std::span' to preserve bounds information}}
92   foo(ap2[1]);    // expected-note{{used in buffer access here}}
93 }
94 
95 void testUnevaluatedContext(int * p) {// no-warning
96   foo(sizeof(p[1]),             // no-warning
97       sizeof(decltype(p[1])));  // no-warning
98 }
99 
100 // expected-note@+1{{change type of 'a' to 'std::span' to preserve bounds information}}
101 void testQualifiedParameters(const int * p, const int * const q, const int a[10], const int b[10][10]) {
102   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
103   // expected-warning@-2{{'q' is an unsafe pointer used for buffer access}}
104   // expected-warning@-3{{'a' is an unsafe pointer used for buffer access}}
105   // expected-warning@-4{{'b' is an unsafe pointer used for buffer access}}
106 
107   foo(p[1], 1[p], p[-1],    // expected-note3{{used in buffer access here}}
108       q[1], 1[q], q[-1],    // expected-note3{{used in buffer access here}}
109       a[1],                 // expected-note{{used in buffer access here}}     `a` is of pointer type
110       b[1][2]               // expected-note{{used in buffer access here}}     `b[1]` is of array type
111                             // expected-warning@-1{{unsafe buffer access}}
112       );
113 }
114 
115 struct T {
116   int a[10];
117   int * b;
118   struct {
119     int a[10];
120     int * b;
121   } c;
122 };
123 
124 typedef struct T T_t;
125 
126 T_t funRetT();
127 T_t * funRetTStar();
128 
129 void testStructMembers(struct T * sp, struct T s, T_t * sp2, T_t s2) {
130   foo(sp->a[1],     // expected-warning{{unsafe buffer access}}
131       sp->b[1],     // expected-warning{{unsafe buffer access}}
132       sp->c.a[1],   // expected-warning{{unsafe buffer access}}
133       sp->c.b[1],   // expected-warning{{unsafe buffer access}}
134       s.a[1],       // expected-warning{{unsafe buffer access}}
135       s.b[1],       // expected-warning{{unsafe buffer access}}
136       s.c.a[1],     // expected-warning{{unsafe buffer access}}
137       s.c.b[1],     // expected-warning{{unsafe buffer access}}
138       sp2->a[1],    // expected-warning{{unsafe buffer access}}
139       sp2->b[1],    // expected-warning{{unsafe buffer access}}
140       sp2->c.a[1],  // expected-warning{{unsafe buffer access}}
141       sp2->c.b[1],  // expected-warning{{unsafe buffer access}}
142       s2.a[1],      // expected-warning{{unsafe buffer access}}
143       s2.b[1],      // expected-warning{{unsafe buffer access}}
144       s2.c.a[1],           // expected-warning{{unsafe buffer access}}
145       s2.c.b[1],           // expected-warning{{unsafe buffer access}}
146       funRetT().a[1],      // expected-warning{{unsafe buffer access}}
147       funRetT().b[1],      // expected-warning{{unsafe buffer access}}
148       funRetTStar()->a[1], // expected-warning{{unsafe buffer access}}
149       funRetTStar()->b[1]  // expected-warning{{unsafe buffer access}}
150       );
151 }
152 
153 int garray[10];     // expected-warning{{'garray' is an unsafe buffer that does not perform bounds checks}}
154 int * gp = garray;  // expected-warning{{'gp' is an unsafe pointer used for buffer access}}
155 int gvar = gp[1];   // FIXME: file scope unsafe buffer access is not warned
156 
157 void testLambdaCaptureAndGlobal(int * p) {
158   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
159   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
160 
161   auto Lam = [p, a]() {
162     return p[1]           // expected-note{{used in buffer access here}}
163       + a[1] + garray[1]  // expected-note2{{used in buffer access here}}
164       + gp[1];            // expected-note{{used in buffer access here}}
165 
166   };
167 }
168 
169 auto file_scope_lambda = [](int *ptr) {
170   // expected-warning@-1{{'ptr' is an unsafe pointer used for buffer access}}
171 
172   ptr[5] = 10;  // expected-note{{used in buffer access here}}
173 };
174 
175 void testLambdaCapture() {
176   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
177   int b[10];              // expected-warning{{'b' is an unsafe buffer that does not perform bounds checks}}
178   int c[10];
179 
180   auto Lam1 = [a]() {
181     return a[1];           // expected-note{{used in buffer access here}}
182   };
183 
184   auto Lam2 = [x = b[3]]() { // expected-note{{used in buffer access here}}
185     return x;
186   };
187 
188   auto Lam = [x = c]() { // expected-warning{{'x' is an unsafe pointer used for buffer access}}
189     return x[3]; // expected-note{{used in buffer access here}}
190   };
191 }
192 
193 void testLambdaImplicitCapture() {
194   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
195   int b[10];              // expected-warning{{'b' is an unsafe buffer that does not perform bounds checks}}
196 
197   auto Lam1 = [=]() {
198     return a[1];           // expected-note{{used in buffer access here}}
199   };
200 
201   auto Lam2 = [&]() {
202     return b[1];           // expected-note{{used in buffer access here}}
203   };
204 }
205 
206 typedef T_t * T_ptr_t;
207 
208 void testTypedefs(T_ptr_t p) {
209   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
210   foo(p[1],       // expected-note{{used in buffer access here}}
211       p[1].a[1],  // expected-note{{used in buffer access here}}
212                   // expected-warning@-1{{unsafe buffer access}}
213       p[1].b[1]   // expected-note{{used in buffer access here}}
214                   // expected-warning@-1{{unsafe buffer access}}
215       );
216 }
217 
218 template<typename T, int N> T f(T t, T * pt, T a[N], T (&b)[N]) {
219   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
220   // expected-warning@-2{{'pt' is an unsafe pointer used for buffer access}}
221   // expected-warning@-3{{'a' is an unsafe pointer used for buffer access}}
222   // expected-warning@-4{{'b' is an unsafe buffer that does not perform bounds checks}}
223   foo(pt[1],    // expected-note{{used in buffer access here}}
224       a[1],     // expected-note{{used in buffer access here}}
225       b[1]);    // expected-note{{used in buffer access here}}
226   return &t[1]; // expected-note{{used in buffer access here}}
227 }
228 
229 // Testing pointer arithmetic for pointer-to-int, qualified multi-level
230 // pointer, pointer to a template type, and auto type
231 T_ptr_t getPtr();
232 
233 template<typename T>
234 void testPointerArithmetic(int * p, const int **q, T * x) {
235 // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
236 // expected-warning@-2{{'x' is an unsafe pointer used for buffer access}}
237   int a[10];
238   auto y = &a[0]; // expected-warning{{'y' is an unsafe pointer used for buffer access}}
239 
240   foo(p + 1, 1 + p, p - 1,      // expected-note3{{used in pointer arithmetic here}}
241       *q + 1, 1 + *q, *q - 1,   // expected-warning3{{unsafe pointer arithmetic}}
242       x + 1, 1 + x, x - 1,      // expected-note3{{used in pointer arithmetic here}}
243       y + 1, 1 + y, y - 1,      // expected-note3{{used in pointer arithmetic here}}
244       getPtr() + 1, 1 + getPtr(), getPtr() - 1 // expected-warning3{{unsafe pointer arithmetic}}
245       );
246 
247   p += 1;  p -= 1;  // expected-note2{{used in pointer arithmetic here}}
248   *q += 1; *q -= 1; // expected-warning2{{unsafe pointer arithmetic}}
249   y += 1; y -= 1;   // expected-note2{{used in pointer arithmetic here}}
250   x += 1; x -= 1;   // expected-note2{{used in pointer arithmetic here}}
251 }
252 
253 void testTemplate(int * p) {
254   int *a[10];
255   foo(f(p, &p, a, a)[1]); // expected-warning{{unsafe buffer access}}
256                           // FIXME: expected note@-1{{in instantiation of function template specialization 'f<int *, 10>' requested here}}
257 
258   const int **q = const_cast<const int **>(&p);
259 
260   testPointerArithmetic(p, q, p); //FIXME: expected note{{in instantiation of}}
261 }
262 
263 void testPointerToMember() {
264   struct S_t {
265     int x;
266     int * y;
267   } S;
268 
269   int S_t::* p = &S_t::x;
270   int * S_t::* q = &S_t::y;
271 
272   foo(S.*p,
273       (S.*q)[1]);  // expected-warning{{unsafe buffer access}}
274 }
275 
276 // test that nested callable definitions are scanned only once
277 void testNestedCallableDefinition(int * p) {
278   class A {
279     void inner(int * p) {
280       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
281       p++; // expected-note{{used in pointer arithmetic here}}
282     }
283 
284     static void innerStatic(int * p) {
285       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
286       p++; // expected-note{{used in pointer arithmetic here}}
287     }
288 
289     void innerInner(int * p) {
290       auto Lam = [p]() {
291         int * q = p;    // expected-warning{{'q' is an unsafe pointer used for buffer access}}
292         q++;            // expected-note{{used in pointer arithmetic here}}
293         return *q;
294       };
295     }
296   };
297 
298   auto Lam = [p]() {
299     int * q = p;  // expected-warning{{'q' is an unsafe pointer used for buffer access}}
300     q++;          // expected-note{{used in pointer arithmetic here}}
301     return *q;
302   };
303 
304   auto LamLam = [p]() {
305     auto Lam = [p]() {
306       int * q = p;  // expected-warning{{'q' is an unsafe pointer used for buffer access}}
307       q++;          // expected-note{{used in pointer arithmetic here}}
308       return *q;
309     };
310   };
311 
312   void (^Blk)(int*) = ^(int *p) {
313     // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
314     p++;   // expected-note{{used in pointer arithmetic here}}
315   };
316 
317   void (^BlkBlk)(int*) = ^(int *p) {
318     void (^Blk)(int*) = ^(int *p) {
319       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
320       p++;   // expected-note{{used in pointer arithmetic here}}
321     };
322     Blk(p);
323   };
324 
325   // lambda and block as call arguments...
326   foo( [p]() { int * q = p; // expected-warning{{'q' is an unsafe pointer used for buffer access}}
327               q++;          // expected-note{{used in pointer arithmetic here}}
328               return *q;
329        },
330        ^(int *p) {  // expected-warning{{'p' is an unsafe pointer used for buffer access}}
331         p++;        // expected-note{{used in pointer arithmetic here}}
332        }
333      );
334 }
335 
336 int testVariableDecls(int * p) {
337   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
338   int * q = p++;      // expected-note{{used in pointer arithmetic here}}
339   int a[p[1]];        // expected-note{{used in buffer access here}}
340   int b = p[1];       // expected-note{{used in buffer access here}}
341   return p[1];        // expected-note{{used in buffer access here}}
342 }
343 
344 template<typename T> void fArr(T t[]) {
345   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
346   foo(t[1]);    // expected-note{{used in buffer access here}}
347   T ar[8];      // expected-warning{{'ar' is an unsafe buffer that does not perform bounds checks}}
348   foo(ar[5]);   // expected-note{{used in buffer access here}}
349 }
350 
351 template void fArr<int>(int t[]); // FIXME: expected note {{in instantiation of}}
352 
353 int testReturn(int t[]) {// expected-note{{change type of 't' to 'std::span' to preserve bounds information}}
354   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
355   return t[1]; // expected-note{{used in buffer access here}}
356 }
357 
358 int testArrayAccesses(int n) {
359     // auto deduced array type
360     int cArr[2][3] = {{1, 2, 3}, {4, 5, 6}};
361     // expected-warning@-1{{'cArr' is an unsafe buffer that does not perform bounds checks}}
362     int d = cArr[0][0];
363     foo(cArr[0][0]);
364     foo(cArr[1][2]);        // expected-note{{used in buffer access here}}
365                             // expected-warning@-1{{unsafe buffer access}}
366     auto cPtr = cArr[1][2]; // expected-note{{used in buffer access here}}
367                             // expected-warning@-1{{unsafe buffer access}}
368     foo(cPtr);
369 
370     // Typdefs
371     typedef int A[3];
372     const A tArr = {4, 5, 6};
373     // expected-warning@-1{{'tArr' is an unsafe buffer that does not perform bounds checks}}
374     foo(tArr[0], tArr[1]);  // expected-note{{used in buffer access here}}
375     return cArr[0][1];      // expected-warning{{unsafe buffer access}}
376 }
377 
378 void testArrayPtrArithmetic(int x[]) { // expected-warning{{'x' is an unsafe pointer used for buffer access}}
379   foo (x + 3); // expected-note{{used in pointer arithmetic here}}
380 
381   int y[3] = {0, 1, 2}; // expected-warning{{'y' is an unsafe buffer that does not perform bounds checks}}
382   foo(y + 4); // expected-note{{used in pointer arithmetic here}}
383 }
384 
385 void testMultiLineDeclStmt(int * p) {
386   int
387 
388   *
389 
390   ap1 = p;      // expected-warning{{'ap1' is an unsafe pointer used for buffer access}} \
391          	   expected-note{{change type of 'ap1' to 'std::span' to preserve bounds information}}
392 
393   foo(ap1[1]);  // expected-note{{used in buffer access here}}
394 }
395 
396 #endif
397