Prohibit string changes by "s"/"z" specifier of `mrb_get_args()`

- The `s` specifier is a string pointer obtained without performing `mrb_str_modify()`, so it cannot be changed.
- The `z` specifier cannot be changed because it is a string pointer obtained by `RSTRING_CSTR()` which returns `const char *`.

1 files changed, 4 insertions, 2 deletions

diff --git a/mrbgems/mruby-socket/src/socket.c b/mrbgems/mruby-socket/src/socket.c
index 916309bcf..a819dcb29 100644
--- a/mrbgems/mruby-socket/src/socket.c
+++ b/mrbgems/mruby-socket/src/socket.c
@@ -515,7 +515,8 @@ static mrb_value
 mrb_ipsocket_ntop(mrb_state *mrb, mrb_value klass)
 {
   mrb_int af, n;
-  char *addr, buf[50];
+  const char *addr;
+  char buf[50];
 
   mrb_get_args(mrb, "is", &af, &addr, &n);
   if ((af == AF_INET && n != 4) || (af == AF_INET6 && n != 16))
@@ -529,7 +530,8 @@ static mrb_value
 mrb_ipsocket_pton(mrb_state *mrb, mrb_value klass)
 {
   mrb_int af, n;
-  char *bp, buf[50];
+  const char *bp;
+  char buf[50];
 
   mrb_get_args(mrb, "is", &af, &bp, &n);
   if ((size_t)n > sizeof(buf) - 1)