Attachment 676 Details for Bug 463 – Simpler OpenBSD patch based on feedback from Markus

[patch] Simpler OpenBSD patch based on feedback from Markus

openbsd-loginmsg2.patch (text/plain), 8.47 KB, created by Darren Tucker on 2004-07-03 15:19:17 AEST

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Creator: Darren Tucker

Created: 2004-07-03 15:19:17 AEST

Size: 8.47 KB

patch

obsolete

>
>This is an update of the previous patch, based on feedback from
>Markus.  It's simpler: it eliminates the extra monitor call, instead it
>sends the message back as an addition message with mm_answer_pty().
>
>It also skips reading lastlog if PrintLastLog=no.
>
>This also means it can't double-up login messages if 2 sessions are
>created in parallel.
>
>To test:
>$ sudo chmod 600 /var/log/lastlog
>$ ssh -MS ~/.ssh/ctl localhost
>$ ssh -S ~/.ssh/ctl localhost
>
>Without this patch, as a non-root user you won't get "Last login..."
>messages in either the master or slave.  Test OK with and without privsep.
>
>Previous patch: 9 files changed, 97 insertions(+), 20 deletions(-)
>This patch: 6 files changed, 79 insertions(+), 25 deletions(-)
>
>Index: monitor.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/monitor.c,v
>retrieving revision 1.60
>diff -u -p -r1.60 monitor.c
>--- monitor.c	22 Jun 2004 05:05:45 -0000	1.60
>+++ monitor.c	3 Jul 2004 04:42:57 -0000
>@@ -73,6 +73,7 @@ extern u_char session_id[];
> extern Buffer input, output;
> extern Buffer auth_debug;
> extern int auth_debug_init;
>+extern Buffer loginmsg;
> 
> /* State exported from the child */
> 
>@@ -1051,10 +1052,6 @@ mm_answer_pty(int sock, Buffer *m)
> 
> 	buffer_put_int(m, 1);
> 	buffer_put_cstring(m, s->tty);
>-	mm_request_send(sock, MONITOR_ANS_PTY, m);
>-
>-	mm_send_fd(sock, s->ptyfd);
>-	mm_send_fd(sock, s->ttyfd);
> 
> 	/* We need to trick ttyslot */
> 	if (dup2(s->ttyfd, 0) == -1)
>@@ -1064,6 +1061,16 @@ mm_answer_pty(int sock, Buffer *m)
> 
> 	/* Now we can close the file descriptor again */
> 	close(0);
>+
>+	/* send messages generated by record_login */
>+	buffer_append(&loginmsg, "\0", 1);
>+	buffer_put_cstring(m, buffer_ptr(&loginmsg));
>+	buffer_clear(&loginmsg);
>+
>+	mm_request_send(sock, MONITOR_ANS_PTY, m);
>+
>+	mm_send_fd(sock, s->ptyfd);
>+	mm_send_fd(sock, s->ttyfd);
> 
> 	/* make sure nothing uses fd 0 */
> 	if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
>Index: monitor_wrap.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/monitor_wrap.c,v
>retrieving revision 1.37
>diff -u -p -r1.37 monitor_wrap.c
>--- monitor_wrap.c	22 Jun 2004 05:05:45 -0000	1.37
>+++ monitor_wrap.c	3 Jul 2004 04:42:57 -0000
>@@ -63,6 +63,7 @@ extern z_stream incoming_stream;
> extern z_stream outgoing_stream;
> extern struct monitor *pmonitor;
> extern Buffer input, output;
>+extern Buffer loginmsg;
> 
> int
> mm_is_monitor(void)
>@@ -632,7 +633,7 @@ int
> mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen)
> {
> 	Buffer m;
>-	char *p;
>+	char *p, *msg;
> 	int success = 0;
> 
> 	buffer_init(&m);
>@@ -648,10 +649,14 @@ mm_pty_allocate(int *ptyfd, int *ttyfd, 
> 		return (0);
> 	}
> 	p = buffer_get_string(&m, NULL);
>+	msg = buffer_get_string(&m, NULL);
> 	buffer_free(&m);
> 
> 	strlcpy(namebuf, p, namebuflen); /* Possible truncation */
> 	xfree(p);
>+
>+	buffer_append(&loginmsg, msg, strlen(msg));
>+	xfree(msg);
> 
> 	*ptyfd = mm_receive_fd(pmonitor->m_recvfd);
> 	*ttyfd = mm_receive_fd(pmonitor->m_recvfd);
>Index: session.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/session.c,v
>retrieving revision 1.177
>diff -u -p -r1.177 session.c
>--- session.c	30 Jun 2004 08:36:59 -0000	1.177
>+++ session.c	3 Jul 2004 04:42:59 -0000
>@@ -94,6 +94,7 @@ extern int debug_flag;
> extern u_int utmp_len;
> extern int startup_pipe;
> extern void destroy_sensitive_data(void);
>+extern Buffer loginmsg;
> 
> /* original command from peer. */
> const char *original_command = NULL;
>@@ -189,6 +190,15 @@ auth_input_request_forwarding(struct pas
> 	return 1;
> }
> 
>+static void
>+display_loginmsg(void)
>+{
>+        if (buffer_len(&loginmsg) > 0) {
>+                buffer_append(&loginmsg, "\0", 1);
>+                printf("%s", (char *)buffer_ptr(&loginmsg));
>+                buffer_clear(&loginmsg);
>+        }
>+}
> 
> void
> do_authenticated(Authctxt *authctxt)
>@@ -586,6 +596,13 @@ do_exec(Session *s, const char *command)
> 		do_exec_no_pty(s, command);
> 
> 	original_command = NULL;
>+
>+	/*
>+	 * Clear loginmsg: it's the child's responsibility to display
>+	 * it to the user, otherwise multiple sessions may accumulate
>+	 * multiple copies of the login messages.
>+	 */
>+	buffer_clear(&loginmsg);
> }
> 
> 
>@@ -593,7 +610,6 @@ do_exec(Session *s, const char *command)
> void
> do_login(Session *s, const char *command)
> {
>-	char *time_string;
> 	socklen_t fromlen;
> 	struct sockaddr_storage from;
> 	struct passwd * pw = s->pw;
>@@ -623,16 +639,7 @@ do_login(Session *s, const char *command
> 	if (check_quietlogin(s, command))
> 		return;
> 
>-	if (options.print_lastlog && s->last_login_time != 0) {
>-		time_string = ctime(&s->last_login_time);
>-		if (strchr(time_string, '\n'))
>-			*strchr(time_string, '\n') = 0;
>-		if (strcmp(s->hostname, "") == 0)
>-			printf("Last login: %s\r\n", time_string);
>-		else
>-			printf("Last login: %s from %s\r\n", time_string,
>-			    s->hostname);
>-	}
>+	display_loginmsg();
> 
> 	do_motd();
> }
>@@ -1377,12 +1384,6 @@ session_pty_req(Session *s)
> 	if (s->ttyfd != -1) {
> 		packet_disconnect("Protocol error: you already have a pty.");
> 		return 0;
>-	}
>-	/* Get the time and hostname when the user last logged in. */
>-	if (options.print_lastlog) {
>-		s->hostname[0] = '\0';
>-		s->last_login_time = get_last_login_time(s->pw->pw_uid,
>-		    s->pw->pw_name, s->hostname, sizeof(s->hostname));
> 	}
> 
> 	s->term = packet_get_string(&len);
>Index: session.h
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/session.h,v
>retrieving revision 1.22
>diff -u -p -r1.22 session.h
>--- session.h	27 Apr 2004 09:46:37 -0000	1.22
>+++ session.h	3 Jul 2004 04:42:59 -0000
>@@ -39,9 +39,6 @@ struct Session {
> 	int	ptyfd, ttyfd, ptymaster;
> 	u_int	row, col, xpixel, ypixel;
> 	char	tty[TTYSZ];
>-	/* last login */
>-	char	hostname[MAXHOSTNAMELEN];
>-	time_t	last_login_time;
> 	/* X11 */
> 	u_int	display_number;
> 	char	*display;
>Index: sshd.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/sshd.c,v
>retrieving revision 1.297
>diff -u -p -r1.297 sshd.c
>--- sshd.c	26 Jun 2004 20:07:16 -0000	1.297
>+++ sshd.c	3 Jul 2004 04:43:00 -0000
>@@ -208,6 +208,9 @@ struct monitor *pmonitor = NULL;
> /* global authentication context */
> Authctxt *the_authctxt = NULL;
> 
>+/* message to be displayed after login */
>+Buffer loginmsg;
>+
> /* Prototypes for various functions defined later in this file. */
> void destroy_sensitive_data(void);
> void demote_sensitive_data(void);
>@@ -1603,6 +1606,9 @@ main(int ac, char **av)
> 	if (use_privsep)
> 		if (privsep_preauth(authctxt) == 1)
> 			goto authenticated;
>+
>+	/* prepare buffer to collect messages to display to user after login */
>+	buffer_init(&loginmsg);
> 
> 	/* perform the key exchange */
> 	/* authenticate user and start session */
>Index: sshlogin.c
>===================================================================
>RCS file: /cvs/src/usr.bin/ssh/sshlogin.c,v
>retrieving revision 1.8
>diff -u -p -r1.8 sshlogin.c
>--- sshlogin.c	21 Jun 2004 17:36:31 -0000	1.8
>+++ sshlogin.c	3 Jul 2004 04:43:00 -0000
>@@ -45,6 +45,11 @@ RCSID("$OpenBSD: sshlogin.c,v 1.8 2004/0
> #include <utmp.h>
> #include "sshlogin.h"
> #include "log.h"
>+#include "buffer.h"
>+#include "servconf.h"
>+
>+extern Buffer loginmsg;
>+extern ServerOptions options;
> 
> /*
>  * Returns the time when the user last logged in.  Returns 0 if the
>@@ -79,6 +84,36 @@ get_last_login_time(uid_t uid, const cha
> }
> 
> /*
>+ * Generate and store last login message.  This must be done before
>+ * login_login() is called and lastlog is updated.
>+ */
>+void
>+store_lastlog_message(const char *user, uid_t uid)
>+{
>+	char *time_string, hostname[MAXHOSTNAMELEN] = "", buf[512];
>+	time_t last_login_time;
>+
>+	if (!options.print_lastlog)
>+		return;
>+
>+	last_login_time = get_last_login_time(uid, user, hostname,
>+	    sizeof(hostname));
>+
>+	if (last_login_time != 0) {
>+		time_string = ctime(&last_login_time);
>+		if (strchr(time_string, '\n'))
>+		    *strchr(time_string, '\n') = 0;
>+		if (strcmp(hostname, "") == 0)
>+			snprintf(buf, sizeof(buf), "Last login: %s\r\n",
>+			    time_string);
>+		else
>+			snprintf(buf, sizeof(buf), "Last login: %s from %s\r\n",
>+			    time_string, hostname);
>+		buffer_append(&loginmsg, buf, strlen(buf));
>+	}
>+}
>+
>+/*
>  * Records that the user has logged in.  I wish these parts of operating
>  * systems were more standardized.
>  */
>@@ -90,6 +125,9 @@ record_login(pid_t pid, const char *tty,
> 	struct lastlog ll;
> 	char *lastlog;
> 	struct utmp u;
>+
>+	/* save previous login details before writing new */
>+	store_lastlog_message(user, uid);
> 
> 	/* Construct an utmp/wtmp entry. */
> 	memset(&u, 0, sizeof(u));

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