Fix strncat/wcsncat

Previously, no checks were done when __n <= __b, but strncat _appends_ after
existing content, making this a overly broad check check. For example, with an
8-byte buffer containing "12345\0", strncat(buf, "ABCD", 4) would have the
check skipped, but the result "12345ABCD\0" is 10 bytes, resulting in an
overflow.

This commit fixes this oversight, and adds a bunch of tests.

1 files changed, 0 insertions, 2 deletions

diff --git a/tests/test_strncat_dynamic_write.c b/tests/test_strncat_dynamic_write.c
index d5c5a94..c538339 100644
--- a/tests/test_strncat_dynamic_write.c
+++ b/tests/test_strncat_dynamic_write.c
@@ -7,11 +7,9 @@ int main(int argc, char** argv) {
   strncat(buffer, "1234567", 5);
   puts(buffer);
 
-#if 0
   CHK_FAIL_START
   strncat(buffer, argv[1], argc);
   CHK_FAIL_END
-#endif
 
   puts(buffer);
   return ret;