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 FUZZ_WRAPFD_H
#define FUZZ_WRAPFD_H

#include "includes.h"
#include "buffer.h"

enum wrapfd_mode {
    UNUSED = 0,
    COMMONBUF, // using the common buffer
    DUMMY, // reads return fixed output, of random length
};

// buf is a common buffer read by all wrapped FDs. doesn't take ownership of buf
void wrapfd_setup(buffer *buf);
void wrapfd_setseed(uint32_t seed);
int wrapfd_new_fuzzinput(void);
int wrapfd_new_dummy(void);

// called via #defines for read/write/select
int wrapfd_read(int fd, void *out, size_t count);
int wrapfd_write(int fd, const void* in, size_t count);
int wrapfd_select(int nfds, fd_set *readfds, fd_set *writefds, 
    fd_set *exceptfds, struct timeval *timeout);
int wrapfd_close(int fd);
int fuzz_kill(pid_t pid, int sig);

#endif // FUZZ_WRAPFD_H