Add cli_pull_reply

Along the lines of cli_request_send this abstracts away the smb-level buffer
handling when parsing replies we got from the server.
(This used to be commit 253134d3aaa359fdfb665709dd5686f69af7f8fd)

3 files changed, 81 insertions, 10 deletions

diff --git a/source3/libsmb/async_smb.c b/source3/libsmb/async_smb.c
index e58b753da2..32f0e8abd6 100644
--- a/source3/libsmb/async_smb.c
+++ b/source3/libsmb/async_smb.c
@@ -230,6 +230,60 @@ struct async_req *cli_request_send(TALLOC_CTX *mem_ctx,
 	return result;
 }
 
+/**
+ * @brief Pull reply data out of a request
+ * @param[in] req		The request that we just received a reply for
+ * @param[out] pwct		How many words did the server send?
+ * @param[out] pvwv		The words themselves
+ * @param[out] pnum_bytes	How many bytes did the server send?
+ * @param[out] pbytes		The bytes themselves
+ * @retval Was the reply formally correct?
+ */
+
+NTSTATUS cli_pull_reply(struct async_req *req,
+			uint8_t *pwct, uint16_t **pvwv,
+			uint16_t *pnum_bytes, uint8_t **pbytes)
+{
+	struct cli_request *cli_req = cli_request_get(req);
+	uint8_t wct, cmd;
+	uint16_t num_bytes;
+	size_t wct_ofs, bytes_offset;
+	NTSTATUS status;
+
+	status = cli_pull_error(cli_req->inbuf);
+
+	if (NT_STATUS_IS_ERR(status)) {
+		cli_set_error(cli_req->cli, status);
+		return status;
+	}
+
+	cmd = CVAL(cli_req->inbuf, smb_com);
+	wct_ofs = smb_wct;
+
+	wct = CVAL(cli_req->inbuf, wct_ofs);
+
+	bytes_offset = wct_ofs + 1 + wct * sizeof(uint16_t);
+	num_bytes = SVAL(cli_req->inbuf, bytes_offset);
+
+	/*
+	 * wct_ofs is a 16-bit value plus 4, wct is a 8-bit value, num_bytes
+	 * is a 16-bit value. So bytes_offset being size_t should be far from
+	 * wrapping.
+	 */
+
+	if ((bytes_offset + 2 > talloc_get_size(cli_req->inbuf))
+	    || (bytes_offset > 0xffff)) {
+		return NT_STATUS_INVALID_NETWORK_RESPONSE;
+	}
+
+	*pwct = wct;
+	*pvwv = (uint16_t *)(cli_req->inbuf + wct_ofs + 1);
+	*pnum_bytes = num_bytes;
+	*pbytes = (uint8_t *)cli_req->inbuf + bytes_offset + 2;
+
+	return NT_STATUS_OK;
+}
+
 /*
  * Convenience function to get the SMB part out of an async_req
  */
diff --git a/source3/libsmb/clifile.c b/source3/libsmb/clifile.c
index dfb0ce8c11..b3032a08eb 100644
--- a/source3/libsmb/clifile.c
+++ b/source3/libsmb/clifile.c
@@ -902,7 +902,10 @@ struct async_req *cli_open_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 
 NTSTATUS cli_open_recv(struct async_req *req, int *fnum)
 {
-	struct cli_request *cli_req = cli_request_get(req);
+	uint8_t wct;
+	uint16_t *vwv;
+	uint16_t num_bytes;
+	uint8_t *bytes;
 	NTSTATUS status;
 
 	SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
@@ -910,12 +913,16 @@ NTSTATUS cli_open_recv(struct async_req *req, int *fnum)
 		return req->status;
 	}
 
-	status = cli_pull_error(cli_req->inbuf);
+	status = cli_pull_reply(req, &wct, &vwv, &num_bytes, &bytes);
 	if (!NT_STATUS_IS_OK(status)) {
 		return status;
 	}
 
-	*fnum = SVAL(cli_req->inbuf, smb_vwv2);
+	if (wct < 3) {
+		return NT_STATUS_INVALID_NETWORK_RESPONSE;
+	}
+
+	*fnum = SVAL(vwv+2, 0);
 
 	return NT_STATUS_OK;
 }
@@ -974,14 +981,17 @@ struct async_req *cli_close_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 
 NTSTATUS cli_close_recv(struct async_req *req)
 {
-	struct cli_request *cli_req = cli_request_get(req);
+	uint8_t wct;
+	uint16_t *vwv;
+	uint16_t num_bytes;
+	uint8_t *bytes;
 
 	SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
 	if (req->state == ASYNC_REQ_ERROR) {
 		return req->status;
 	}
 
-	return cli_pull_error(cli_req->inbuf);
+	return cli_pull_reply(req, &wct, &vwv, &num_bytes, &bytes);
 }
 
 bool cli_close(struct cli_state *cli, int fnum)
diff --git a/source3/libsmb/clireadwrite.c b/source3/libsmb/clireadwrite.c
index d2c8f3c1ba..b64a4c68f3 100644
--- a/source3/libsmb/clireadwrite.c
+++ b/source3/libsmb/clireadwrite.c
@@ -104,6 +104,10 @@ NTSTATUS cli_read_andx_recv(struct async_req *req, ssize_t *received,
 			    uint8_t **rcvbuf)
 {
 	struct cli_request *cli_req = cli_request_get(req);
+	uint8_t wct;
+	uint16_t *vwv;
+	uint16_t num_bytes;
+	uint8_t *bytes;
 	NTSTATUS status;
 	size_t size;
 
@@ -112,24 +116,27 @@ NTSTATUS cli_read_andx_recv(struct async_req *req, ssize_t *received,
 		return req->status;
 	}
 
-	status = cli_pull_error(cli_req->inbuf);
+	status = cli_pull_reply(req, &wct, &vwv, &num_bytes, &bytes);
 
 	if (NT_STATUS_IS_ERR(status)) {
 		return status;
 	}
 
+	if (wct < 12) {
+		return NT_STATUS_INVALID_NETWORK_RESPONSE;
+	}
+
 	/* size is the number of bytes the server returned.
 	 * Might be zero. */
-	size = SVAL(cli_req->inbuf, smb_vwv5);
-	size |= (((unsigned int)(SVAL(cli_req->inbuf, smb_vwv7))) << 16);
+	size = SVAL(vwv + 5, 0);
+	size |= (((unsigned int)SVAL(vwv + 7, 0)) << 16);
 
 	if (size > cli_req->data.read.size) {
 		DEBUG(5,("server returned more than we wanted!\n"));
 		return NT_STATUS_UNEXPECTED_IO_ERROR;
 	}
 
-	*rcvbuf = (uint8_t *)
-		(smb_base(cli_req->inbuf) + SVAL(cli_req->inbuf, smb_vwv6));
+	*rcvbuf = (uint8_t *)(smb_base(cli_req->inbuf) + SVAL(vwv + 6, 0));
 	*received = size;
 	return NT_STATUS_OK;
 }