* ossl.c: should protect allback Proc not to jump over the library's stack ftame.

1 files changed, 34 insertions, 10 deletions

diff --git a/ossl.c b/ossl.c
index eb8c48b..48a9461 100644
--- a/ossl.c
+++ b/ossl.c
@@ -183,20 +183,44 @@ string2hex(char *buf, int buf_len, char **hexbuf, int *hexbuf_len)
 /*
  * our default PEM callback
  */
+static VALUE
+ossl_pem_passwd_cb0(VALUE flag)
+{	
+    VALUE pass;
+
+    pass = rb_yield(flag);
+    SafeStringValue(pass);
+
+    return pass;
+}
+
 int
-ossl_pem_passwd_cb(char *buf, int max_len, int verify, void *pwd)
+ossl_pem_passwd_cb(char *buf, int max_len, int flag, void *pwd)
 {
-    int len;
-    VALUE ver;
+    int len, status;
+    VALUE rflag, pass;
     
-    if (pwd || !rb_block_given_p()) return PEM_def_callback(buf, max_len, verify, pwd);
-
-    ver = verify ? Qtrue : Qfalse;
-    while (1) {
-	VALUE pass = rb_yield(ver);
-	SafeStringValue(pass);
+    if (pwd || !rb_block_given_p())
+	return PEM_def_callback(buf, max_len, flag, pwd);
+
+    while(1){
+	/*
+	 * when the flag is nonzero, this passphrase
+	 * will be used to perform encryption; otherwise it will
+	 * be used to perform decryption.
+	 */
+	rflag = flag ? Qtrue : Qfalse;
+	pass  = rb_protect(ossl_pem_passwd_cb0, rflag, &status);
+	if(status) return -1; /* exception was raised. */
 	len = RSTRING(pass)->len;
-	if (len < 4 || len>max_len) continue; /* 4 is OpenSSL hardcoded limit */
+	if (len < 4){ /* 4 is OpenSSL hardcoded limit */
+	    rb_warning("password must be longer than 4 bytes");
+	    continue;
+	}
+	if (len > max_len){
+	    rb_warning("password must be shorter then %d bytes", max_len-1);
+	    continue;
+	}
 	memcpy(buf, RSTRING(pass)->ptr, len);
 	break;
     }