Don't check privsep user or path when unprivileged

If running with privsep (mandatory now) as a non-privileged user, we
don't chroot or change to an unprivileged user however we still checked
the existence of the user and directory.  Don't do those checks if we're
not going to use them.  Based in part on a patch from Lionel Fourquaux
via Corinna Vinschen, ok djm@

1 files changed, 5 insertions, 3 deletions

diff --git a/sshd.c b/sshd.c
index 010a2c38..197c4ec8 100644
--- a/sshd.c
+++ b/sshd.c
@@ -223,6 +223,7 @@ int startup_pipe;		/* in child */
 int use_privsep = -1;
 struct monitor *pmonitor = NULL;
 int privsep_is_preauth = 1;
+static int privsep_chroot = 1;
 
 /* global authentication context */
 Authctxt *the_authctxt = NULL;
@@ -541,7 +542,7 @@ privsep_preauth_child(void)
 	demote_sensitive_data();
 
 	/* Demote the child */
-	if (getuid() == 0 || geteuid() == 0) {
+	if (privsep_chroot) {
 		/* Change our root directory */
 		if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
 			fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
@@ -1640,8 +1641,9 @@ main(int ac, char **av)
 	);
 
 	/* Store privilege separation user for later use if required. */
+	privsep_chroot = use_privsep && (getuid() == 0 || geteuid() == 0);
 	if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
-		if (use_privsep || options.kerberos_authentication)
+		if (privsep_chroot || options.kerberos_authentication)
 			fatal("Privilege separation user %s does not exist",
 			    SSH_PRIVSEP_USER);
 	} else {
@@ -1767,7 +1769,7 @@ main(int ac, char **av)
 		    key_type(key));
 	}
 
-	if (use_privsep) {
+	if (privsep_chroot) {
 		struct stat st;
 
 		if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||