encoding.c: rb_enc_find_index2

* string.c (str_undump): use rb_enc_find_index2 to find encoding
  by unterminated string.  check the format before encoding name.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61396 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

encindex.h

@@ -57,6 +57,8 @@ enum ruby_preserved_encindex {
 #define rb_utf8_encindex()      RUBY_ENCINDEX_UTF_8
 #define rb_usascii_encindex()   RUBY_ENCINDEX_US_ASCII
 
+int rb_enc_find_index2(const char *name, long len);
+
 #if defined(__cplusplus)
 #if 0
 { /* satisfy cc-mode */

encoding.c

@@ -724,6 +724,17 @@ rb_enc_find_index(const char *name)
     return i;
 }
 
+int
+rb_enc_find_index2(const char *name, long len)
+{
+    char buf[ENCODING_NAMELEN_MAX+1];
+
+    if (len > ENCODING_NAMELEN_MAX) return -1;
+    memcpy(buf, name, len);
+    buf[len] = '\0';
+    return rb_enc_find_index(buf);
+}
+
 rb_encoding *
 rb_enc_find(const char *name)
 {

string.c

@@ -6263,7 +6263,6 @@ str_undump(VALUE str)
 	    }
 	    else {
 		const char *encname;
-		char *buf;
 		int encidx;
 		ptrdiff_t size;
 
@@ -6280,22 +6279,14 @@ str_undump(VALUE str)
 		s = memchr(s, '"', s_end-s);
 		size = s - encname;
 		if (!s) goto invalid_format;
-		if (size > 100) {
-		    rb_raise(rb_eRuntimeError, "dumped string has unknown encoding name");
-		}
-		buf = ALLOC_N(char, size+1);
-		memcpy(buf, encname, size);
-		buf[size] = '\0';
-		encidx = rb_enc_find_index(buf);
-		xfree(buf);
+		if (s_end - s != 2) goto invalid_format;
+		if (s[0] != '"' || s[1] != ')') goto invalid_format;
+
+		encidx = rb_enc_find_index2(encname, (long)size);
 		if (encidx < 0) {
 		    rb_raise(rb_eRuntimeError, "dumped string has unknown encoding name");
 		}
 		rb_enc_associate_index(undumped, encidx);
-
-		if (s_end - s != 2 ||
-			s[0] != '"' ||
-			s[1] != ')') goto invalid_format;
 	    }
 	    break;
 	}