From 57611240a972932ef26a13c6998a7fa90fd33371 Mon Sep 17 00:00:00 2001
From: dearblue <dearblue@users.osdn.me>
Date: Thu, 24 Sep 2020 22:25:26 +0900
Subject: 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 *`.
---
 mrbgems/mruby-eval/src/eval.c         | 10 +++++-----
 mrbgems/mruby-io/src/file.c           |  3 ++-
 mrbgems/mruby-socket/src/socket.c     |  6 ++++--
 mrbgems/mruby-string-ext/src/string.c | 10 ++++++----
 4 files changed, 17 insertions(+), 12 deletions(-)

(limited to 'mrbgems')

diff --git a/mrbgems/mruby-eval/src/eval.c b/mrbgems/mruby-eval/src/eval.c
index eaf07cabe..af6837b81 100644
--- a/mrbgems/mruby-eval/src/eval.c
+++ b/mrbgems/mruby-eval/src/eval.c
@@ -12,7 +12,7 @@ mrb_value mrb_obj_instance_eval(mrb_state *mrb, mrb_value self);
 void mrb_codedump_all(mrb_state*, struct RProc*);
 
 static struct RProc*
-create_proc_from_string(mrb_state *mrb, char *s, mrb_int len, mrb_value binding, const char *file, mrb_int line)
+create_proc_from_string(mrb_state *mrb, const char *s, mrb_int len, mrb_value binding, const char *file, mrb_int line)
 {
   mrbc_context *cxt;
   struct mrb_parser_state *p;
@@ -131,10 +131,10 @@ exec_irep(mrb_state *mrb, mrb_value self, struct RProc *proc)
 static mrb_value
 f_eval(mrb_state *mrb, mrb_value self)
 {
-  char *s;
+  const char *s;
   mrb_int len;
   mrb_value binding = mrb_nil_value();
-  char *file = NULL;
+  const char *file = NULL;
   mrb_int line = 1;
   struct RProc *proc;
 
@@ -154,9 +154,9 @@ f_instance_eval(mrb_state *mrb, mrb_value self)
   mrb_get_args(mrb, "*!&", &argv, &argc, &b);
 
   if (mrb_nil_p(b)) {
-    char *s;
+    const char *s;
     mrb_int len;
-    char *file = NULL;
+    const char *file = NULL;
     mrb_int line = 1;
     mrb_value cv;
     struct RProc *proc;
diff --git a/mrbgems/mruby-io/src/file.c b/mrbgems/mruby-io/src/file.c
index d3c4b3885..53ed4b69d 100644
--- a/mrbgems/mruby-io/src/file.c
+++ b/mrbgems/mruby-io/src/file.c
@@ -557,7 +557,8 @@ mrb_file_s_readlink(mrb_state *mrb, mrb_value klass) {
   mrb_raise(mrb, E_NOTIMP_ERROR, "readlink is not supported on this platform");
   return mrb_nil_value(); // unreachable
 #else
-  char *path, *buf, *tmp;
+  const char *path;
+  char *buf, *tmp;
   size_t bufsize = 100;
   ssize_t rc;
   mrb_value ret;
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)
diff --git a/mrbgems/mruby-string-ext/src/string.c b/mrbgems/mruby-string-ext/src/string.c
index 7cf146ec8..ded34a89e 100644
--- a/mrbgems/mruby-string-ext/src/string.c
+++ b/mrbgems/mruby-string-ext/src/string.c
@@ -1072,7 +1072,8 @@ static mrb_value
 mrb_str_del_prefix_bang(mrb_state *mrb, mrb_value self)
 {
   mrb_int plen, slen;
-  char *ptr, *s;
+  const char *ptr;
+  char *s;
   struct RString *str = RSTRING(self);
 
   mrb_get_args(mrb, "s", &ptr, &plen);
@@ -1105,7 +1106,7 @@ static mrb_value
 mrb_str_del_prefix(mrb_state *mrb, mrb_value self)
 {
   mrb_int plen, slen;
-  char *ptr;
+  const char *ptr;
 
   mrb_get_args(mrb, "s", &ptr, &plen);
   slen = RSTRING_LEN(self);
@@ -1129,7 +1130,8 @@ static mrb_value
 mrb_str_del_suffix_bang(mrb_state *mrb, mrb_value self)
 {
   mrb_int plen, slen;
-  char *ptr, *s;
+  const char *ptr;
+  char *s;
   struct RString *str = RSTRING(self);
 
   mrb_get_args(mrb, "s", &ptr, &plen);
@@ -1160,7 +1162,7 @@ static mrb_value
 mrb_str_del_suffix(mrb_state *mrb, mrb_value self)
 {
   mrb_int plen, slen;
-  char *ptr;
+  const char *ptr;
 
   mrb_get_args(mrb, "s", &ptr, &plen);
   slen = RSTRING_LEN(self);
-- 
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