str-idna: cleanups in IDNA handling

Ensure safe operation even with broken libidn2, and make
sure that we properly allocate memory to caller, even on complex
library configuration.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>

diff --git a/lib/str-idna.c b/lib/str-idna.c
index 61f1f6e7e65231745e7147f1e73df73fe51074a3..383560ca3fbfb6de88e22319a56776d1e13e14b7 100644 (file)
--- a/lib/str-idna.c
+++ b/lib/str-idna.c
@@ -33,6 +33,13 @@
 #endif
 
 #if defined HAVE_LIBIDN2 || defined HAVE_LIBIDN
+
+#ifdef HAVE_LIBIDN2
+# define IDN_FREE idn2_free
+#else
+# define IDN_FREE idn_free
+#endif
+
 /**
  * gnutls_idna_map:
  * @input: contain the UTF-8 formatted domain name
@@ -87,7 +94,7 @@ int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out, unsig
        }
 
 #ifdef HAVE_LIBIDN2
-#if IDN2_VERSION_NUMBER >= 0x00140000
+# if IDN2_VERSION_NUMBER >= 0x00140000
        /* IDN2_NONTRANSITIONAL automatically converts to lowercase
         * IDN2_NFC_INPUT converts to NFC before toASCII conversion
         *
@@ -97,11 +104,12 @@ int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out, unsig
         * we provide IDN2_NFC_INPUT. */
 
        rc = idn2_lookup_u8((uint8_t *)istr.data, (uint8_t **)&idna, IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL);
-#else
+# else
        rc = idn2_lookup_u8((uint8_t *)istr.data, (uint8_t **)&idna, IDN2_NFC_INPUT);
-#endif
+# endif
        if (rc != IDN2_OK) {
                gnutls_assert();
+               idna = NULL; /* in case idn2_lookup_u8 modifies &idna */
                _gnutls_debug_log("unable to convert name '%s' to IDNA format: %s\n", istr.data, idn2_strerror(rc));
                ret = GNUTLS_E_INVALID_UTF8_STRING;
                goto fail;
@@ -116,7 +124,7 @@ int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out, unsig
        }
 #endif
 
-       if (gnutls_malloc != malloc) {
+       if (gnutls_free != IDN_FREE) {
                ret = _gnutls_set_strdatum(out, idna, strlen(idna));
        } else  {
                out->data = (unsigned char*)idna;
@@ -124,12 +132,9 @@ int gnutls_idna_map(const char *input, unsigned ilen, gnutls_datum_t *out, unsig
                idna = NULL;
                ret = 0;
        }
+
  fail:
-#ifdef HAVE_LIBIDN2
-       idn2_free(idna);
-#else
-       idn_free(idna);
-#endif
+       IDN_FREE(idna);
        gnutls_free(istr.data);
        return ret;
 }