s3: Attempt to fix bug 7518

If select returns -1, we can't rely on the fd sets. The current code might loop
endlessly because when putting an invalid fd (the closed socket?) on the read
set, a select implementation might choose not to touch it but directly return
with EINVAL. Thus run_events will see the socket readable, which leads to a
"return true", and thus a NT_STATUS_RETRY -> same game again.

We should never get into this situation, but to me the logfiles given in bug
7518 do not reveal enough information to understand how this can happen.

1 files changed, 6 insertions, 6 deletions

diff --git a/source3/smbd/process.c b/source3/smbd/process.c
index 66be77efce..4db54f39c0 100644
--- a/source3/smbd/process.c
+++ b/source3/smbd/process.c
@@ -991,6 +991,12 @@ static NTSTATUS smbd_server_connection_loop_once(struct smbd_server_connection *
 		errno = sav;
 	}
 
+	/* Check if error */
+	if (selrtn == -1) {
+		/* something is wrong. Maybe the socket is dead? */
+		return map_nt_error_from_unix(errno);
+	}
+
         if ((conn->smb1.echo_handler.trusted_fd != -1)
 	    && FD_ISSET(conn->sock, &r_fds)
 	    && FD_ISSET(conn->smb1.echo_handler.trusted_fd, &r_fds)) {
@@ -1006,12 +1012,6 @@ static NTSTATUS smbd_server_connection_loop_once(struct smbd_server_connection *
 		return NT_STATUS_RETRY;
 	}
 
-	/* Check if error */
-	if (selrtn == -1) {
-		/* something is wrong. Maybe the socket is dead? */
-		return map_nt_error_from_unix(errno);
-	}
-
 	/* Did we timeout ? */
 	if (selrtn == 0) {
 		return NT_STATUS_RETRY;