--- a/sshd.c

+++ b/sshd.c

@@ -1420,6 +1420,8 @@ server_accept_loop(struct ssh *ssh, int

 				    options.log_level,

 				    options.log_facility,

 				    log_stderr);

+

+				set_log_session_id();  // Set log session ID for this session

 				if (rexec_flag)

 					close(config_s[0]);

 				else {

--- a/log.c

+++ b/log.c

@@ -410,17 +410,17 @@ do_log(LogLevel level, int force, const

 		tmp_handler(level, force, fmtbuf, log_handler_ctx);

 		log_handler = tmp_handler;

 	} else if (log_on_stderr) {

-		snprintf(msgbuf, sizeof msgbuf, "%.*s\r\n",

-		    (int)sizeof msgbuf - 3, fmtbuf);

+		snprintf(msgbuf, sizeof msgbuf, "%.*s session=%s\r\n",

+		    (int)sizeof msgbuf - 3, fmtbuf, get_log_session_id());

 		(void)write(log_stderr_fd, msgbuf, strlen(msgbuf));

 	} else {

 #if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT)

 		openlog_r(argv0 ? argv0 : __progname, LOG_PID, log_facility, &sdata);

-		syslog_r(pri, &sdata, "%.500s", fmtbuf);

+		syslog_r(pri, &sdata, "%.500s session=%s", fmtbuf, get_log_session_id());

 		closelog_r(&sdata);

 #else

 		openlog(argv0 ? argv0 : __progname, LOG_PID, log_facility);

-		syslog(pri, "%.500s", fmtbuf);

+		syslog(pri, "%.500s session=%s", fmtbuf, get_log_session_id());

 		closelog();

 #endif

 	}

@@ -452,6 +452,33 @@ sshlogdie(const char *file, const char *

 }

 void

+set_log_session_id()

+{

+        struct timeval tv;

+        char hostname[HOST_NAME_MAX + 1];

+        char session_id[HOST_NAME_MAX + 20];

+        char *s;

+        if (gethostname(hostname, sizeof(hostname)) != 0) {

+                *hostname = '\0';

+        }

+        gettimeofday(&tv, NULL);

+        snprintf(session_id, sizeof(session_id), "%s:%x.%x",

+                 hostname, tv.tv_sec, tv.tv_usec);

+        setenv("LOG_SESSION_ID", session_id, 1);

+}

+

+const char *

+get_log_session_id()

+{

+        const char *id = getenv("LOG_SESSION_ID");

+        if (!id) {

+                 set_log_session_id();

+                 id = getenv("LOG_SESSION_ID");

+        }

+        return id;

+}

+

+void

 sshsigdie(const char *file, const char *func, int line, int showfunc,

     LogLevel level, const char *suffix, const char *fmt, ...)

 {

--- /dev/null

+++ b/regress/session-id.sh

@@ -0,0 +1,23 @@

+tid="session id"

+

+start_sshd

+

+${SSH} -F $OBJ/ssh_config somehost true

+if [ $? -ne 0 ]; then

+	fail "ssh connect with failed"

+fi

+

+expected="session=$(hostname)"

+

+# grab the first session ID which will be stable across session

+sessionid=$(grep -m1 $expected $TEST_SSHD_LOGFILE | sed -E 's/.*(session=.*)/\1/')

+

+line_count=$(grep -c $expected $TEST_SSHD_LOGFILE)

+if [ $line_count == "0" ]; then

+	fail "No session ID lines found"

+fi

+

+stable_id_count=$(grep -c $sessionid $TEST_SSHD_LOGFILE)

+if [ $line_count != $stable_id_count ]; then

+	fail 'Mismatching session ids found'

+fi

--- a/log.h

+++ b/log.h

@@ -68,6 +68,9 @@ const char *	log_level_name(LogLevel);

 void	 set_log_handler(log_handler_fn *, void *);

 void	 cleanup_exit(int) __attribute__((noreturn));

+void		set_log_session_id();

+const char *	get_log_session_id();

+

 void	 sshlog(const char *, const char *, int, int,

     LogLevel, const char *, const char *, ...)

     __attribute__((format(printf, 7, 8)));

--- a/session.c

+++ b/session.c

@@ -1256,6 +1256,10 @@ do_setup_env(struct ssh *ssh, Session *s

 		child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",

 		    original_command);

+  /* set LOG_SESSION_ID for child */

+  child_set_env(&env, &envsize, "LOG_SESSION_ID", get_log_session_id());

+  debug("set LOG_SESION_ID to: %s", get_log_session_id());

+

 	if (debug_flag) {

 		/* dump the environment */

 		fprintf(stderr, "Environment:\n");