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[Clang][Sema] Add fortify warnings for stpcpy #141646

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Merged
merged 1 commit into from
Jun 3, 2025
Merged

[Clang][Sema] Add fortify warnings for stpcpy #141646

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3 changes: 3 additions & 0 deletions clang/lib/Sema/SemaChecking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1257,6 +1257,8 @@ void Sema::checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD,
switch (BuiltinID) {
default:
return;
case Builtin::BI__builtin_stpcpy:
case Builtin::BIstpcpy:
case Builtin::BI__builtin_strcpy:
case Builtin::BIstrcpy: {
DiagID = diag::warn_fortify_strlen_overflow;
Expand All @@ -1265,6 +1267,7 @@ void Sema::checkFortifiedBuiltinMemoryFunction(FunctionDecl *FD,
break;
}

case Builtin::BI__builtin___stpcpy_chk:
case Builtin::BI__builtin___strcpy_chk: {
DiagID = diag::warn_fortify_strlen_overflow;
SourceSize = ComputeStrLenArgument(1);
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8 changes: 8 additions & 0 deletions clang/test/Sema/warn-fortify-source.c
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Expand Up @@ -71,6 +71,14 @@ void call_strcpy_nowarn(void) {
__builtin_strcpy(dst, src);
}

void call_stpcpy(void) {
const char *const src = "abcd";
char dst1[5];
char dst2[4];
__builtin_stpcpy(dst1, src);
__builtin_stpcpy(dst2, src); // expected-warning {{'stpcpy' will always overflow; destination buffer has size 4, but the source string has length 5 (including NUL byte)}}
}

void call_memmove(void) {
char s1[10], s2[20];
__builtin_memmove(s2, s1, 20);
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