[PATCH v3 3/4] libs/ldap: sasl_decode() should treat intput buffer as data + token.

[Dmitry Timoshkov]

From: Dmitry Timoshkov

Cyrus SALS plugin treats it this way:
https://github.com/cyrusimap/cyrus-sasl/blob/master/plugins/gssapi.c

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55304
Signed-off-by: Dmitry Timoshkov 
---
 libs/ldap/libldap/sasl_w.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/libs/ldap/libldap/sasl_w.c b/libs/ldap/libldap/sasl_w.c
index 61b68de7e26..2fa09bfd652 100644
--- a/libs/ldap/libldap/sasl_w.c
+++ b/libs/ldap/libldap/sasl_w.c
@@ -71,28 +71,35 @@ int sasl_decode( sasl_conn_t *handle, const char *input, unsigned int inputlen,
     unsigned int len;
     SecBuffer bufs[2] =
     {
-        { conn->trailer_size, SECBUFFER_TOKEN, NULL },
-        { inputlen - conn->trailer_size - sizeof(len), SECBUFFER_DATA, NULL }
+        { 0, SECBUFFER_DATA, NULL },
+        { conn->trailer_size, SECBUFFER_TOKEN, NULL }
     };
     SecBufferDesc buf_desc = { SECBUFFER_VERSION, ARRAYSIZE(bufs), bufs };
     SECURITY_STATUS status;
     int ret;

+    ldap_log_printf( NULL, LDAP_DEBUG_TRACE, "sasl_decode: %p,%u\n", input, inputlen );
+
     if (inputlen < sizeof(len) + conn->trailer_size) return SASL_FAIL;
+    len = ntohl( *(unsigned int *)input );
+    if (inputlen < sizeof(len) + len) return SASL_FAIL;
+
+    if ((ret = grow_buffer( conn, len )) < 0) return ret;
+    memcpy( conn->buf, input + sizeof(len), len );

-    if ((ret = grow_buffer( conn, inputlen - sizeof(len) )) < 0) return ret;
-    memcpy( conn->buf, input + sizeof(len), inputlen - sizeof(len) );
     bufs[0].pvBuffer = conn->buf;
-    bufs[1].pvBuffer = conn->buf + conn->trailer_size;
+    bufs[0].cbBuffer = len - conn->trailer_size;
+    bufs[1].pvBuffer = conn->buf + bufs[0].cbBuffer;

status = DecryptMessage( &conn->ctxt_handle, &buf_desc, 0, NULL );
     if (status == SEC_E_OK)
     {
-        *output = bufs[1].pvBuffer;
-        *outputlen = bufs[1].cbBuffer;
+        *output = bufs[0].pvBuffer;
+        *outputlen = bufs[0].cbBuffer;
+        return SASL_OK;
     }

-    return (status == SEC_E_OK) ? SASL_OK : SASL_FAIL;
+    return SASL_FAIL;
 }

int sasl_encode( sasl_conn_t *handle, const char *input, unsigned int inputlen, const char **output,