make SFTP more robust at keeping track of state during rekey

Author: JacobBarthelmeh

src/wolfsftp.c

@@ -7746,11 +7746,11 @@ int wolfSSH_SFTP_SendReadPacket(WOLFSSH* ssh, byte* handle, word32 handleSz,
                 /* Get response */
                 if ((ret = SFTP_GetHeader(ssh, &state->reqId, &state->type,
                                 &state->buffer)) <= 0) {
-                    if (!NoticeError(ssh)) {
-                        state->state = STATE_SEND_READ_CLEANUP;
-                        continue;
+                    if (NoticeError(ssh)) {
+                        return WS_FATAL_ERROR;
                     }
-                    return WS_FATAL_ERROR;
+                    state->state = STATE_SEND_READ_CLEANUP;
+                    continue;
                 }
                 ret = wolfSSH_SFTP_buffer_create(ssh, &state->buffer, ret);
                 if (ret != WS_SUCCESS) {
@@ -7789,11 +7789,11 @@ int wolfSSH_SFTP_SendReadPacket(WOLFSSH* ssh, byte* handle, word32 handleSz,
                 /* get size of string and place it into out buffer */
                 ret = wolfSSH_stream_read(ssh, szFlat, UINT32_SZ);
                 if (ret < 0) {
-                    if (!NoticeError(ssh)) {
-                        state->state = STATE_SEND_READ_CLEANUP;
-                        continue;
+                    if (NoticeError(ssh)) {
+                        return WS_FATAL_ERROR;
                     }
-                    return ret;
+                    state->state = STATE_SEND_READ_CLEANUP;
+                    continue;
                 }
                 ato32(szFlat, &sz);
                 wolfSSH_SFTP_buffer_create(ssh, &state->buffer, sz);
@@ -7814,8 +7814,7 @@ int wolfSSH_SFTP_SendReadPacket(WOLFSSH* ssh, byte* handle, word32 handleSz,
                             out + state->recvSz,
                             wolfSSH_SFTP_buffer_size(&state->buffer));
                     if (ret < 0) {
-                        if (ssh->error == WS_WANT_READ ||
-                                ssh->error == WS_WANT_WRITE) {
+                        if (NoticeError(ssh)) {
                             return WS_FATAL_ERROR;
                         }
                         WLOG(WS_LOG_SFTP, "Error reading remainder of data");
@@ -7852,12 +7851,11 @@ int wolfSSH_SFTP_SendReadPacket(WOLFSSH* ssh, byte* handle, word32 handleSz,
                     ret = wolfSSH_SFTP_buffer_read(ssh, &state->buffer,
                             wolfSSH_SFTP_buffer_size(&state->buffer));
                     if (ret < 0) {
-                        if (ssh->error != WS_WANT_READ &&
-                            ssh->error != WS_WANT_WRITE) {
-                            state->state = STATE_SEND_READ_CLEANUP;
-                            continue;
+                        if (NoticeError(ssh)) {
+                            return WS_FATAL_ERROR;
                         }
-                        return WS_FATAL_ERROR;
+                        state->state = STATE_SEND_READ_CLEANUP;
+                        continue;
                     }
                     wolfSSH_SFTP_buffer_rewind(&state->buffer);
                     ret = wolfSSH_SFTP_DoStatus(ssh,