smbd: Create the proper error blob for STOPPED_ON_SYMLINK

Unused so far, our lowerlevel routines so far never return
NT_STATUS_STOPPED_ON_SYMLINK. Also see the NULL passed as
"symlink_reparse", this will change soon. Separate patch for easier
review.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

diff --git a/source3/smbd/smb2_create.c b/source3/smbd/smb2_create.c
index b92d73616455905644879d84a13e40b8d15bf87a..fe65ac2f590807bbed7db271842fb6340547da21 100644 (file)
--- a/source3/smbd/smb2_create.c
+++ b/source3/smbd/smb2_create.c
@@ -33,6 +33,7 @@
 #include "lib/util_ea.h"
 #include "source3/passdb/lookup_sid.h"
 #include "source3/modules/util_reparse.h"
+#include "libcli/smb/reparse.h"
 
 #undef DBGC_CLASS
 #define DBGC_CLASS DBGC_SMB2
@@ -318,6 +319,122 @@ static uint64_t get_mid_from_smb2req(struct smbd_smb2_request *smb2req)
        return BVAL(reqhdr, SMB2_HDR_MESSAGE_ID);
 }
 
+/*
+ * [MS-SMB2] 2.2.2.1 SMB2 ERROR Context Response
+ */
+static bool smbd_smb2_create_symlink_error_context_response(
+       TALLOC_CTX *mem_ctx,
+       struct reparse_data_buffer *symlink_reparse,
+       uint8_t **_resp,
+       size_t *_resplen)
+{
+       ssize_t symlink_buffer_len;
+       size_t symlink_error_response_len, error_context_response_len;
+       uint8_t *resp = NULL;
+
+       SMB_ASSERT(symlink_reparse->tag == IO_REPARSE_TAG_SYMLINK);
+
+       symlink_buffer_len = reparse_data_buffer_marshall(symlink_reparse,
+                                                         NULL,
+                                                         0);
+       if (symlink_buffer_len < 0) {
+               DBG_DEBUG("reparse_data_buffer_marshall() failed\n");
+               goto fail;
+       }
+
+       /* 2.2.2.2.1 Symbolic Link Error Response */
+       symlink_error_response_len = symlink_buffer_len + 8;
+       if (symlink_error_response_len < (size_t)symlink_buffer_len) {
+               goto fail;
+       }
+
+       /* 2.2.2.1 SMB2 ERROR Context Response */
+       error_context_response_len = symlink_error_response_len + 8;
+       if (error_context_response_len < symlink_error_response_len) {
+               goto fail;
+       }
+
+       resp = talloc_array(mem_ctx, uint8_t, error_context_response_len);
+       if (resp == NULL) {
+               goto fail;
+       }
+       PUSH_LE_U32(resp, 0, symlink_error_response_len); /* ErrorDataLength */
+       PUSH_LE_U32(resp, 4, 0);                          /* ErrorId */
+       PUSH_LE_U32(resp,
+                   8,
+                   symlink_error_response_len - 4); /* SymLinkLength */
+       PUSH_LE_U32(resp, 12, 0x4C4D5953);
+
+       reparse_data_buffer_marshall(symlink_reparse,
+                                    resp + 16,
+                                    symlink_buffer_len);
+
+       *_resp = resp;
+       *_resplen = error_context_response_len;
+       return true;
+fail:
+       TALLOC_FREE(resp);
+       return false;
+}
+
+static NTSTATUS smbd_smb2_create_error(
+       struct smbd_smb2_request *smb2req,
+       NTSTATUS status,
+       struct reparse_data_buffer *symlink_reparse)
+{
+       struct smbXsrv_connection *xconn = smb2req->xconn;
+       NTSTATUS error;
+       DATA_BLOB resp = {
+               .data = NULL,
+       };
+       bool ok;
+
+       if (!NT_STATUS_EQUAL(status, NT_STATUS_STOPPED_ON_SYMLINK)) {
+               error = smbd_smb2_request_error(smb2req, status);
+               return error;
+       }
+
+       ok = smbd_smb2_create_symlink_error_context_response(smb2req,
+                                                            symlink_reparse,
+                                                            &resp.data,
+                                                            &resp.length);
+       if (!ok) {
+               error = smbd_smb2_request_error(smb2req, NT_STATUS_NO_MEMORY);
+               return error;
+       }
+
+       if (xconn->protocol < PROTOCOL_SMB3_11) {
+               /*
+                * smbd_smb2_create_symlink_error_context_response()
+                * has created a smb3.11 SMB2 ERROR Context from
+                * [MS-SMB2] 2.2.2.1. This has an 8-byte header before
+                * the symlink response.
+                */
+               DATA_BLOB symlink_error = {
+                       .data = resp.data + 8,
+                       .length = resp.length - 8,
+               };
+
+               SMB_ASSERT(resp.length >= 8);
+
+               error = smbd_smb2_request_error_ex(
+                       smb2req,
+                       NT_STATUS_STOPPED_ON_SYMLINK,
+                       0,
+                       &symlink_error,
+                       __location__);
+       } else {
+               error = smbd_smb2_request_error_ex(
+                       smb2req,
+                       NT_STATUS_STOPPED_ON_SYMLINK,
+                       1,
+                       &resp,
+                       __location__);
+       }
+
+       return error;
+}
+
 static void smbd_smb2_request_create_done(struct tevent_req *tsubreq)
 {
        struct smbd_smb2_request *smb2req = tevent_req_callback_data(tsubreq,
@@ -362,7 +479,7 @@ static void smbd_smb2_request_create_done(struct tevent_req *tsubreq)
                if (smbd_smb2_is_compound(smb2req)) {
                        smb2req->compound_create_err = status;
                }
-               error = smbd_smb2_request_error(smb2req, status);
+               error = smbd_smb2_create_error(smb2req, status, NULL);
                if (!NT_STATUS_IS_OK(error)) {
                        smbd_server_connection_terminate(smb2req->xconn,
                                                         nt_errstr(error));