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: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/ 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 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403

#ifndef DBMALLOC_H_
#define DBMALLOC_H_

#include "options.h"
#include <stdint.h>
#include <stdlib.h>

void * m_malloc(size_t size);
void * m_calloc(size_t nmemb, size_t size);
void * m_strdup(const char * str);
void * m_realloc(void* ptr, size_t size);

#if DROPBEAR_TRACKING_MALLOC
void m_free_direct(void* ptr);
void m_malloc_set_epoch(unsigned int epoch);
void m_malloc_free_epoch(unsigned int epoch, int dofree);

#else
/* plain wrapper */
#define m_free_direct free

#endif

#define m_free(X) do {m_free_direct(X); (X) = NULL;} while (0)


#endif /* DBMALLOC_H_ */