5 files changed, 22 insertions, 0 deletions

diff --git a/include/string.h b/include/string.h
index 778d22a..925e572 100644
--- a/include/string.h
+++ b/include/string.h
@@ -189,8 +189,15 @@ _FORTIFY_FN(stpncpy) char *stpncpy(char * _FORTIFY_POS0 __d, const char *__s,
 #if __has_builtin(__builtin___stpncpy_chk) && USE_NATIVE_CHK
         return __builtin___stpncpy_chk(__d, __s, __n, __fh_bos(__d, 0));
 #else
+#if 0
+        // They check overlap across the whole range of the given length, but
+        // the given length is not what will actually be copied, rather it's
+        // the maximum length (if src is shorter, only length of src will be
+        // copied). This triggers false positives and traps where it shouldn't
+        // (e.g. in ICU tests).
         if (__fh_overlap(__d, __s, __n))
                 __builtin_trap();
+#endif
 
         __fh_size_t __b = __fh_bos(__d, 0);
         if (__n > __b && strlen(__s) + 1 > __b)
@@ -290,8 +297,15 @@ _FORTIFY_FN(strncpy) char *strncpy(char * _FORTIFY_POS0 __d,
 #if __has_builtin(__builtin___strncpy_chk) && USE_NATIVE_CHK
         return __builtin___strncpy_chk(__d, __s, __n, __fh_bos(__d, 0));
 #else
+#if 0
+        // They check overlap across the whole range of the given length, but
+        // the given length is not what will actually be copied, rather it's
+        // the maximum length (if src is shorter, only length of src will be
+        // copied). This triggers false positives and traps where it shouldn't
+        // (e.g. in ICU tests).
         if (__fh_overlap(__d, __s, __n))
                 __builtin_trap();
+#endif
 
         __fh_size_t __b = __fh_bos(__d, 0);
         if (__n > __b)
diff --git a/tests/test_stpncpy_overwrite_over.c b/tests/test_stpncpy_overwrite_over.c
index e66d8d3..004e2b8 100644
--- a/tests/test_stpncpy_overwrite_over.c
+++ b/tests/test_stpncpy_overwrite_over.c
@@ -3,6 +3,7 @@
 #include <string.h>
 
 int main(int argc, char** argv) {
+#if 0
   char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
   puts(buffer);
 
@@ -11,5 +12,6 @@ int main(int argc, char** argv) {
   CHK_FAIL_END
 
   puts(buffer);
+#endif
   return ret;
 }
diff --git a/tests/test_stpncpy_overwrite_under.c b/tests/test_stpncpy_overwrite_under.c
index 5625ff8..845ae29 100644
--- a/tests/test_stpncpy_overwrite_under.c
+++ b/tests/test_stpncpy_overwrite_under.c
@@ -3,6 +3,7 @@
 #include <string.h>
 
 int main(int argc, char** argv) {
+#if 0
   char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
   puts(buffer);
 
@@ -11,5 +12,6 @@ int main(int argc, char** argv) {
   CHK_FAIL_END
 
   puts(buffer);
+#endif
   return ret;
 }
diff --git a/tests/test_strncpy_overwrite_over.c b/tests/test_strncpy_overwrite_over.c
index d584bcc..94b6d2b 100644
--- a/tests/test_strncpy_overwrite_over.c
+++ b/tests/test_strncpy_overwrite_over.c
@@ -3,6 +3,7 @@
 #include <string.h>
 
 int main(int argc, char** argv) {
+#if 0
   char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
   puts(buffer);
 
@@ -11,5 +12,6 @@ int main(int argc, char** argv) {
   CHK_FAIL_END
 
   puts(buffer);
+#endif
   return ret;
 }
diff --git a/tests/test_strncpy_overwrite_under.c b/tests/test_strncpy_overwrite_under.c
index f554b28..8a0a4af 100644
--- a/tests/test_strncpy_overwrite_under.c
+++ b/tests/test_strncpy_overwrite_under.c
@@ -3,6 +3,7 @@
 #include <string.h>
 
 int main(int argc, char** argv) {
+#if 0
   char buffer[9] = {'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', '\0'};
   puts(buffer);
 
@@ -11,5 +12,6 @@ int main(int argc, char** argv) {
   CHK_FAIL_END
 
   puts(buffer);
+#endif
   return ret;
 }