xref: /llvm-project/clang/test/SemaCXX/warn-unsafe-buffer-usage.cpp (revision 33f6161d9eaaa7c5a01ee8e50dec440d3052d34a) 
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) {
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 void testQualifiedParameters(const int * p, const int * const q, const int a[10], const int b[10][10]) {
101   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
102   // expected-warning@-2{{'q' is an unsafe pointer used for buffer access}}
103   // expected-warning@-3{{'a' is an unsafe pointer used for buffer access}}
104   // expected-warning@-4{{'b' is an unsafe pointer used for buffer access}}
105 
106   foo(p[1], 1[p], p[-1],    // expected-note3{{used in buffer access here}}
107       q[1], 1[q], q[-1],    // expected-note3{{used in buffer access here}}
108       a[1],                 // expected-note{{used in buffer access here}}     `a` is of pointer type
109       b[1][2]               // expected-note{{used in buffer access here}}     `b[1]` is of array type
110                             // expected-warning@-1{{unsafe buffer access}}
111       );
112 }
113 
114 struct T {
115   int a[10];
116   int * b;
117   struct {
118     int a[10];
119     int * b;
120   } c;
121 };
122 
123 typedef struct T T_t;
124 
125 T_t funRetT();
126 T_t * funRetTStar();
127 
128 void testStructMembers(struct T * sp, struct T s, T_t * sp2, T_t s2) {
129   foo(sp->a[1],     // expected-warning{{unsafe buffer access}}
130       sp->b[1],     // expected-warning{{unsafe buffer access}}
131       sp->c.a[1],   // expected-warning{{unsafe buffer access}}
132       sp->c.b[1],   // expected-warning{{unsafe buffer access}}
133       s.a[1],       // expected-warning{{unsafe buffer access}}
134       s.b[1],       // expected-warning{{unsafe buffer access}}
135       s.c.a[1],     // expected-warning{{unsafe buffer access}}
136       s.c.b[1],     // expected-warning{{unsafe buffer access}}
137       sp2->a[1],    // expected-warning{{unsafe buffer access}}
138       sp2->b[1],    // expected-warning{{unsafe buffer access}}
139       sp2->c.a[1],  // expected-warning{{unsafe buffer access}}
140       sp2->c.b[1],  // expected-warning{{unsafe buffer access}}
141       s2.a[1],      // expected-warning{{unsafe buffer access}}
142       s2.b[1],      // expected-warning{{unsafe buffer access}}
143       s2.c.a[1],           // expected-warning{{unsafe buffer access}}
144       s2.c.b[1],           // expected-warning{{unsafe buffer access}}
145       funRetT().a[1],      // expected-warning{{unsafe buffer access}}
146       funRetT().b[1],      // expected-warning{{unsafe buffer access}}
147       funRetTStar()->a[1], // expected-warning{{unsafe buffer access}}
148       funRetTStar()->b[1]  // expected-warning{{unsafe buffer access}}
149       );
150 }
151 
152 int garray[10];     // expected-warning{{'garray' is an unsafe buffer that does not perform bounds checks}}
153 int * gp = garray;  // expected-warning{{'gp' is an unsafe pointer used for buffer access}}
154 int gvar = gp[1];   // FIXME: file scope unsafe buffer access is not warned
155 
156 void testLambdaCaptureAndGlobal(int * p) {
157   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
158   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
159 
160   auto Lam = [p, a]() {
161     return p[1]           // expected-note{{used in buffer access here}}
162       + a[1] + garray[1]  // expected-note2{{used in buffer access here}}
163       + gp[1];            // expected-note{{used in buffer access here}}
164 
165   };
166 }
167 
168 auto file_scope_lambda = [](int *ptr) {
169   // expected-warning@-1{{'ptr' is an unsafe pointer used for buffer access}}
170 
171   ptr[5] = 10;  // expected-note{{used in buffer access here}}
172 };
173 
174 void testLambdaCapture() {
175   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
176   int b[10];              // expected-warning{{'b' is an unsafe buffer that does not perform bounds checks}}
177   int c[10];
178 
179   auto Lam1 = [a]() {
180     return a[1];           // expected-note{{used in buffer access here}}
181   };
182 
183   auto Lam2 = [x = b[3]]() { // expected-note{{used in buffer access here}}
184     return x;
185   };
186 
187   auto Lam = [x = c]() { // expected-warning{{'x' is an unsafe pointer used for buffer access}}
188     return x[3]; // expected-note{{used in buffer access here}}
189   };
190 }
191 
192 void testLambdaImplicitCapture() {
193   int a[10];              // expected-warning{{'a' is an unsafe buffer that does not perform bounds checks}}
194   int b[10];              // expected-warning{{'b' is an unsafe buffer that does not perform bounds checks}}
195 
196   auto Lam1 = [=]() {
197     return a[1];           // expected-note{{used in buffer access here}}
198   };
199 
200   auto Lam2 = [&]() {
201     return b[1];           // expected-note{{used in buffer access here}}
202   };
203 }
204 
205 typedef T_t * T_ptr_t;
206 
207 void testTypedefs(T_ptr_t p) {
208   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
209   foo(p[1],       // expected-note{{used in buffer access here}}
210       p[1].a[1],  // expected-note{{used in buffer access here}}
211                   // expected-warning@-1{{unsafe buffer access}}
212       p[1].b[1]   // expected-note{{used in buffer access here}}
213                   // expected-warning@-1{{unsafe buffer access}}
214       );
215 }
216 
217 template<typename T, int N> T f(T t, T * pt, T a[N], T (&b)[N]) {
218   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
219   // expected-warning@-2{{'pt' is an unsafe pointer used for buffer access}}
220   // expected-warning@-3{{'a' is an unsafe pointer used for buffer access}}
221   // expected-warning@-4{{'b' is an unsafe buffer that does not perform bounds checks}}
222   foo(pt[1],    // expected-note{{used in buffer access here}}
223       a[1],     // expected-note{{used in buffer access here}}
224       b[1]);    // expected-note{{used in buffer access here}}
225   return &t[1]; // expected-note{{used in buffer access here}}
226 }
227 
228 // Testing pointer arithmetic for pointer-to-int, qualified multi-level
229 // pointer, pointer to a template type, and auto type
230 T_ptr_t getPtr();
231 
232 template<typename T>
233 void testPointerArithmetic(int * p, const int **q, T * x) {
234 // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
235 // expected-warning@-2{{'x' is an unsafe pointer used for buffer access}}
236   int a[10];
237   auto y = &a[0]; // expected-warning{{'y' is an unsafe pointer used for buffer access}}
238 
239   foo(p + 1, 1 + p, p - 1,      // expected-note3{{used in pointer arithmetic here}}
240       *q + 1, 1 + *q, *q - 1,   // expected-warning3{{unsafe pointer arithmetic}}
241       x + 1, 1 + x, x - 1,      // expected-note3{{used in pointer arithmetic here}}
242       y + 1, 1 + y, y - 1,      // expected-note3{{used in pointer arithmetic here}}
243       getPtr() + 1, 1 + getPtr(), getPtr() - 1 // expected-warning3{{unsafe pointer arithmetic}}
244       );
245 
246   p += 1;  p -= 1;  // expected-note2{{used in pointer arithmetic here}}
247   *q += 1; *q -= 1; // expected-warning2{{unsafe pointer arithmetic}}
248   y += 1; y -= 1;   // expected-note2{{used in pointer arithmetic here}}
249   x += 1; x -= 1;   // expected-note2{{used in pointer arithmetic here}}
250 }
251 
252 void testTemplate(int * p) {
253   int *a[10];
254   foo(f(p, &p, a, a)[1]); // expected-warning{{unsafe buffer access}}
255                           // FIXME: expected note@-1{{in instantiation of function template specialization 'f<int *, 10>' requested here}}
256 
257   const int **q = const_cast<const int **>(&p);
258 
259   testPointerArithmetic(p, q, p); //FIXME: expected note{{in instantiation of}}
260 }
261 
262 void testPointerToMember() {
263   struct S_t {
264     int x;
265     int * y;
266   } S;
267 
268   int S_t::* p = &S_t::x;
269   int * S_t::* q = &S_t::y;
270 
271   foo(S.*p,
272       (S.*q)[1]);  // expected-warning{{unsafe buffer access}}
273 }
274 
275 // test that nested callable definitions are scanned only once
276 void testNestedCallableDefinition(int * p) {
277   class A {
278     void inner(int * p) {
279       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
280       p++; // expected-note{{used in pointer arithmetic here}}
281     }
282 
283     static void innerStatic(int * p) {
284       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
285       p++; // expected-note{{used in pointer arithmetic here}}
286     }
287 
288     void innerInner(int * p) {
289       auto Lam = [p]() {
290         int * q = p;    // expected-warning{{'q' is an unsafe pointer used for buffer access}}
291         q++;            // expected-note{{used in pointer arithmetic here}}
292         return *q;
293       };
294     }
295   };
296 
297   auto Lam = [p]() {
298     int * q = p;  // expected-warning{{'q' is an unsafe pointer used for buffer access}}
299     q++;          // expected-note{{used in pointer arithmetic here}}
300     return *q;
301   };
302 
303   auto LamLam = [p]() {
304     auto Lam = [p]() {
305       int * q = p;  // expected-warning{{'q' is an unsafe pointer used for buffer access}}
306       q++;          // expected-note{{used in pointer arithmetic here}}
307       return *q;
308     };
309   };
310 
311   void (^Blk)(int*) = ^(int *p) {
312     // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
313     p++;   // expected-note{{used in pointer arithmetic here}}
314   };
315 
316   void (^BlkBlk)(int*) = ^(int *p) {
317     void (^Blk)(int*) = ^(int *p) {
318       // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
319       p++;   // expected-note{{used in pointer arithmetic here}}
320     };
321     Blk(p);
322   };
323 
324   // lambda and block as call arguments...
325   foo( [p]() { int * q = p; // expected-warning{{'q' is an unsafe pointer used for buffer access}}
326               q++;          // expected-note{{used in pointer arithmetic here}}
327               return *q;
328        },
329        ^(int *p) {  // expected-warning{{'p' is an unsafe pointer used for buffer access}}
330         p++;        // expected-note{{used in pointer arithmetic here}}
331        }
332      );
333 }
334 
335 int testVariableDecls(int * p) {
336   // expected-warning@-1{{'p' is an unsafe pointer used for buffer access}}
337   int * q = p++;      // expected-note{{used in pointer arithmetic here}}
338   int a[p[1]];        // expected-note{{used in buffer access here}}
339   int b = p[1];       // expected-note{{used in buffer access here}}
340   return p[1];        // expected-note{{used in buffer access here}}
341 }
342 
343 template<typename T> void fArr(T t[]) {
344   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
345   foo(t[1]);    // expected-note{{used in buffer access here}}
346   T ar[8];      // expected-warning{{'ar' is an unsafe buffer that does not perform bounds checks}}
347   foo(ar[5]);   // expected-note{{used in buffer access here}}
348 }
349 
350 template void fArr<int>(int t[]); // FIXME: expected note {{in instantiation of}}
351 
352 int testReturn(int t[]) {// expected-note{{change type of 't' to 'std::span' to preserve bounds information}}
353   // expected-warning@-1{{'t' is an unsafe pointer used for buffer access}}
354   return t[1]; // expected-note{{used in buffer access here}}
355 }
356 
357 int testArrayAccesses(int n) {
358     // auto deduced array type
359     int cArr[2][3] = {{1, 2, 3}, {4, 5, 6}};
360     // expected-warning@-1{{'cArr' is an unsafe buffer that does not perform bounds checks}}
361     int d = cArr[0][0];
362     foo(cArr[0][0]);
363     foo(cArr[1][2]);        // expected-note{{used in buffer access here}}
364                             // expected-warning@-1{{unsafe buffer access}}
365     auto cPtr = cArr[1][2]; // expected-note{{used in buffer access here}}
366                             // expected-warning@-1{{unsafe buffer access}}
367     foo(cPtr);
368 
369     // Typdefs
370     typedef int A[3];
371     const A tArr = {4, 5, 6};
372     // expected-warning@-1{{'tArr' is an unsafe buffer that does not perform bounds checks}}
373     foo(tArr[0], tArr[1]);  // expected-note{{used in buffer access here}}
374     return cArr[0][1];      // expected-warning{{unsafe buffer access}}
375 }
376 
377 void testArrayPtrArithmetic(int x[]) { // expected-warning{{'x' is an unsafe pointer used for buffer access}}
378   foo (x + 3); // expected-note{{used in pointer arithmetic here}}
379 
380   int y[3] = {0, 1, 2}; // expected-warning{{'y' is an unsafe buffer that does not perform bounds checks}}
381   foo(y + 4); // expected-note{{used in pointer arithmetic here}}
382 }
383 
384 void testMultiLineDeclStmt(int * p) {
385   int
386 
387   *
388 
389   ap1 = p;      // expected-warning{{'ap1' is an unsafe pointer used for buffer access}} \
390          	   expected-note{{change type of 'ap1' to 'std::span' to preserve bounds information}}
391 
392   foo(ap1[1]);  // expected-note{{used in buffer access here}}
393 }
394 
395 #endif
396