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https://github.com/Gericom/teak-llvm.git
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b6e16ea006
These diagnose overflowing calls to subset of fortifiable functions. Some functions, like sprintf or strcpy aren't supported right not, but we should probably support these in the future. We previously supported this kind of functionality with -Wbuiltin-memcpy-chk-size, but that diagnostic doesn't work with _FORTIFY implementations that use wrapper functions. Also unlike that diagnostic, we emit these warnings regardless of whether _FORTIFY_SOURCE is actually enabled, which is nice for programs that don't enable the runtime checks. Why not just use diagnose_if, like Bionic does? We can get better diagnostics in the compiler (i.e. mention the sizes), and we have the potential to diagnose sprintf and strcpy which is impossible with diagnose_if (at least, in languages that don't support C++14 constexpr). This approach also saves standard libraries from having to add diagnose_if. rdar://48006655 Differential revision: https://reviews.llvm.org/D58797 llvm-svn: 356397
77 lines
3.6 KiB
C
77 lines
3.6 KiB
C
// RUN: %clang_cc1 -Wstrncat-size -verify -fsyntax-only %s
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// RUN: %clang_cc1 -DUSE_BUILTINS -Wstrncat-size -verify -fsyntax-only %s
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// RUN: %clang_cc1 -fsyntax-only -Wstrncat-size -fixit -x c %s
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// RUN: %clang_cc1 -DUSE_BUILTINS -fsyntax-only -Wstrncat-size -fixit -x c %s
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typedef __SIZE_TYPE__ size_t;
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size_t strlen (const char *s);
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#ifdef USE_BUILTINS
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# define BUILTIN(f) __builtin_ ## f
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#else
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# define BUILTIN(f) f
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#endif
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#define strncat BUILTIN(strncat)
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char *strncat(char *restrict s1, const char *restrict s2, size_t n);
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struct {
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char f1[100];
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char f2[100][3];
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} s4, **s5;
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char s1[100];
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char s2[200];
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int x;
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void test(char *src) {
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char dest[10];
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strncat(dest, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAA", sizeof(dest) - strlen(dest) - 1); // no-warning
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strncat(dest, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAA", sizeof(dest) - 1); // no-warning - the code might assume that dest is empty
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strncat(dest, src, sizeof(src)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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strncat(dest, src, sizeof(src) - 1); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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strncat(dest, "AAAAAAAAAAAAAAAAAAAAAAAAAAA", sizeof(dest)); // expected-warning{{the value of the size argument in 'strncat' is too large, might lead to a buffer overflow}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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strncat(dest, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", sizeof(dest) - strlen(dest)); // expected-warning{{the value of the size argument in 'strncat' is too large, might lead to a buffer overflow}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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strncat((*s5)->f2[x], s2, sizeof(s2)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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strncat(s1+3, s2, sizeof(s2)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-warning {{strncat' size argument is too large; destination buffer has size 97, but size argument is 200}}
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strncat(s4.f1, s2, sizeof(s2)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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}
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// Don't issue FIXIT for flexible arrays.
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struct S {
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int y;
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char x[];
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};
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void flexible_arrays(struct S *s) {
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char str[] = "hi";
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strncat(s->x, str, sizeof(str)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}}
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}
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// Don't issue FIXIT for destinations of size 1.
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void size_1() {
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char z[1];
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char str[] = "hi";
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strncat(z, str, sizeof(z)); // expected-warning{{the value of the size argument to 'strncat' is wrong}}
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}
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// Support VLAs.
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void vlas(int size) {
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char z[size];
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char str[] = "hi";
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strncat(z, str, sizeof(str)); // expected-warning {{size argument in 'strncat' call appears to be size of the source}} expected-note {{change the argument to be the free space in the destination buffer minus the terminating null byte}}
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}
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// Non-array type gets a different error message.
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void f(char* s, char* d) {
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strncat(d, s, sizeof(d)); // expected-warning {{the value of the size argument to 'strncat' is wrong}}
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}
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