changeset 1930:299f4f19ba19

Add /usr/sbin and /sbin to default root PATH When dropbear is used in a very restricted environment (such as in a initrd), the default user shell is often also very restricted and doesn't take care of setting the PATH so the user ends up with the PATH set by dropbear. Unfortunately, dropbear always sets "/usr/bin:/bin" as default PATH even for the root user which should have /usr/sbin and /sbin too. For a concrete instance of this problem, see the "Remote Unlocking" section in this tutorial: It speaks of a bug in the initramfs script because it's written "blkid" instead of "/sbin/blkid"... this is just because the scripts from the initramfs do not expect to have a PATH without the sbin directories and because dropbear is not setting the PATH appropriately for the root user. I'm thus suggesting to use the attached patch to fix this misbehaviour (I did not test it, but it's easy enough). It might seem anecdotic but multiple Kali users have been bitten by this. From
author Raphael Hertzog <>
date Mon, 09 Jul 2018 16:27:53 +0200
parents 315dbcef7293
children b366dfaeae68
files default_options.h svr-chansession.c
diffstat 2 files changed, 6 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/default_options.h	Wed Mar 30 21:42:23 2022 +0800
+++ b/default_options.h	Mon Jul 09 16:27:53 2018 +0200
@@ -339,5 +339,6 @@
 /* The default path. This will often get replaced by the shell */
 #define DEFAULT_PATH "/usr/bin:/bin"
+#define DEFAULT_ROOT_PATH "/usr/sbin:/usr/bin:/sbin:/bin"
--- a/svr-chansession.c	Wed Mar 30 21:42:23 2022 +0800
+++ b/svr-chansession.c	Mon Jul 09 16:27:53 2018 +0200
@@ -1012,7 +1012,11 @@
 	addnewvar("LOGNAME", ses.authstate.pw_name);
 	addnewvar("HOME", ses.authstate.pw_dir);
 	addnewvar("SHELL", get_user_shell());
-	addnewvar("PATH", DEFAULT_PATH);
+	if (getuid() == 0) {
+		addnewvar("PATH", DEFAULT_ROOT_PATH);
+	} else {
+		addnewvar("PATH", DEFAULT_PATH);
+	}
 	if (cp != NULL) {
 		addnewvar("LANG", cp);