Re: xenstored file descriptor leak

From: Manuel Bouyer <bouyer@antioche.eu.org>
To: "Jürgen Groß" <jgross@suse.com>
Cc: xen-devel@lists.xen.org
Subject: Re: xenstored file descriptor leak
Date: Wed, 3 Feb 2021 12:48:32 +0100	[thread overview]
Message-ID: <20210203114832.GA1549@antioche.eu.org> (raw)
In-Reply-To: <89ddaac0-eb05-8ddb-465a-60d78e4009eb@suse.com>

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On Wed, Feb 03, 2021 at 09:21:32AM +0100, Jürgen Groß wrote:
> [...]
> This shouldn't happen in case we are closing the socket actively.
> 
> In the end we should just do a talloc_free(conn) in
> ignore_connection() if it is a socket based one. This should revert
> the critical modification of the XSA-115 fixes for sockets while
> keeping the desired effect for domain connections.

Hello
here's an updated patch which works for me. Does anyone see a problem
with it ? If not I will submit it for commit.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--

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--- xenstored_core.c.orig	2021-02-02 18:06:33.389316841 +0100
+++ xenstored_core.c	2021-02-03 12:46:17.204376338 +0100
@@ -397,9 +397,12 @@
 			     !list_empty(&conn->out_list)))
 				*ptimeout = 0;
 		} else {
-			short events = POLLIN|POLLPRI;
-			if (!list_empty(&conn->out_list))
-				events |= POLLOUT;
+			short events = 0;
+			if (!conn->is_ignored) {
+				events |= POLLIN|POLLPRI;
+			        if (!list_empty(&conn->out_list))
+				        events |= POLLOUT;
+			}
 			conn->pollfd_idx = set_fd(conn->fd, events);
 		}
 	}
@@ -1440,6 +1443,9 @@
 
 	talloc_free(conn->in);
 	conn->in = NULL;
+	/* if this is a socket connection, drop it now */
+	if (conn->fd >= 0)
+		talloc_free(conn);
 }
 
 static const char *sockmsg_string(enum xsd_sockmsg_type type)
