From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35317) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cr16W-00061e-B9 for qemu-devel@nongnu.org; Thu, 23 Mar 2017 07:40:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cr16S-0000Bd-FI for qemu-devel@nongnu.org; Thu, 23 Mar 2017 07:40:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53038) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cr16S-0000As-5o for qemu-devel@nongnu.org; Thu, 23 Mar 2017 07:40:28 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 56D1F64A78 for ; Thu, 23 Mar 2017 11:40:27 +0000 (UTC) References: <1490268208-23368-1-git-send-email-armbru@redhat.com> From: Paolo Bonzini Message-ID: <24dcf0a9-971f-7576-f863-f7db01aa62aa@redhat.com> Date: Thu, 23 Mar 2017 12:40:24 +0100 MIME-Version: 1.0 In-Reply-To: <1490268208-23368-1-git-send-email-armbru@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.9] sockets: Fix socket_address_to_string() hostname truncation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster , qemu-devel@nongnu.org Cc: berrange@redhat.com, kraxel@redhat.com On 23/03/2017 12:23, Markus Armbruster wrote: > We first snprintf() to a fixed buffer, then g_strdup() the result > *boggle*. > > Worse, the size of the fixed buffer INET6_ADDRSTRLEN + 5 + 4 is bogus: > the 4 correctly accounts for '[', ']', ':' and '\0', but > INET6_ADDRSTRLEN is not a suitable limit for inet->host, and 5 is not > one for inet->port! They are for host and port in *numeric* form > (exploiting that INET6_ADDRSTRLEN > INET_ADDRSTRLEN), but inet->host > can also be a hostname, and inet->port can be a service name, to be > resolved with getaddrinfo(). > > Fortunately, the only user so far is the "socket" network backend's > net_socket_connected(), which uses it to initialize a NetSocketState's > info_str[]. info_str[] has considerable more space: 256 instead of > 55. So the bug's impact appears to be limited to truncated "info > networks" with the "socket" network backend. > > The fix is obvious: use g_strdup_printf(). > > Signed-off-by: Markus Armbruster > --- > util/qemu-sockets.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c > index 7c120c4..40164bf 100644 > --- a/util/qemu-sockets.c > +++ b/util/qemu-sockets.c > @@ -1307,19 +1307,14 @@ char *socket_address_to_string(struct SocketAddress *addr, Error **errp) > { > char *buf; > InetSocketAddress *inet; > - char host_port[INET6_ADDRSTRLEN + 5 + 4]; /me learnt about INET6_ADDRSTRLEN today. > switch (addr->type) { > case SOCKET_ADDRESS_KIND_INET: > inet = addr->u.inet.data; > if (strchr(inet->host, ':') == NULL) { > - snprintf(host_port, sizeof(host_port), "%s:%s", inet->host, > - inet->port); > - buf = g_strdup(host_port); > + buf = g_strdup_printf("%s:%s", inet->host, inet->port); > } else { > - snprintf(host_port, sizeof(host_port), "[%s]:%s", inet->host, > - inet->port); > - buf = g_strdup(host_port); > + buf = g_strdup_printf("[%s]:%s", inet->host, inet->port); > } > break; > > Reviewed-by: Paolo Bonzini