Attachment 2175 Details for Bug 1999 – Refactor, always send client banner first for protocol=2

[patch] Refactor, always send client banner first for protocol=2

ssh2-client-banner.diff (text/plain), 3.12 KB, created by Damien Miller on 2012-07-20 11:02:44 AEST

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Creator: Damien Miller

Created: 2012-07-20 11:02:44 AEST

Size: 3.12 KB

patch

obsolete

>Index: sshconnect.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/sshconnect.c,v
>retrieving revision 1.234
>diff -u -p -r1.234 sshconnect.c
>--- sshconnect.c	24 May 2011 07:15:47 -0000	1.234
>+++ sshconnect.c	20 Jul 2012 00:56:33 -0000
>@@ -419,6 +419,24 @@ ssh_connect(const char *host, struct soc
> 	return 0;
> }
> 
>+static void
>+send_client_banner(int connection_out, int minor1)
>+{
>+	char buf[256];
>+
>+	/* Send our own protocol version identification. */
>+	snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
>+	    compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
>+	    compat20 ? PROTOCOL_MINOR_2 : minor1,
>+	    SSH_VERSION, compat20 ? "\r\n" : "\n");
>+	if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
>+	    != strlen(buf))
>+		fatal("write: %.100s", strerror(errno));
>+	client_version_string = xstrdup(buf);
>+	chop(client_version_string);
>+	debug("Local version string %.100s", client_version_string);
>+}
>+
> /*
>  * Waits for the server identification string, and sends our own
>  * identification string.
>@@ -430,7 +448,7 @@ ssh_exchange_identification(int timeout_
> 	int remote_major, remote_minor, mismatch;
> 	int connection_in = packet_get_connection_in();
> 	int connection_out = packet_get_connection_out();
>-	int minor1 = PROTOCOL_MINOR_1;
>+	int minor1 = PROTOCOL_MINOR_1, client_sent = 0;
> 	u_int i, n;
> 	size_t len;
> 	int fdsetsz, remaining, rc;
>@@ -440,6 +458,16 @@ ssh_exchange_identification(int timeout_
> 	fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
> 	fdset = xcalloc(1, fdsetsz);
> 
>+	/*
>+	 * If we are SSH2-only then we can send the banner immediately and
>+	 * save a round-trip.
>+	 */
>+	if (options.protocol == SSH_PROTO_2) {
>+		enable_compat20();
>+		send_client_banner(connection_out, 0);
>+		client_sent = 1;
>+	}
>+
> 	/* Read other side's version identification. */
> 	remaining = timeout_ms;
> 	for (n = 0;;) {
>@@ -542,18 +570,9 @@ ssh_exchange_identification(int timeout_
> 		fatal("Protocol major versions differ: %d vs. %d",
> 		    (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
> 		    remote_major);
>-	/* Send our own protocol version identification. */
>-	snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
>-	    compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
>-	    compat20 ? PROTOCOL_MINOR_2 : minor1,
>-	    SSH_VERSION, compat20 ? "\r\n" : "\n");
>-	if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
>-	    != strlen(buf))
>-		fatal("write: %.100s", strerror(errno));
>-	client_version_string = xstrdup(buf);
>-	chop(client_version_string);
>+	if (!client_sent)
>+		send_client_banner(connection_out, minor1);
> 	chop(server_version_string);
>-	debug("Local version string %.100s", client_version_string);
> }
> 
> /* defaults to 'no' */
>Index: compat.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/compat.c,v
>retrieving revision 1.79
>diff -u -p -r1.79 compat.c
>--- compat.c	23 Sep 2011 07:45:05 -0000	1.79
>+++ compat.c	20 Jul 2012 00:56:33 -0000
>@@ -43,6 +43,8 @@ int datafellows = 0;
> void
> enable_compat20(void)
> {
>+	if (compat20)
>+		return;
> 	debug("Enabling compatibility mode for protocol 2.0");
> 	compat20 = 1;
> }

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