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

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */
#include "tomcrypt.h"

/**
   @file pmac_shift_xor.c
   PMAC implementation, internal function, by Tom St Denis
*/

#ifdef LTC_PMAC

/**
  Internal function.  Performs the state update (adding correct multiple)
  @param pmac   The PMAC state.
*/
void pmac_shift_xor(pmac_state *pmac)
{
   int x, y;
   y = pmac_ntz(pmac->block_index++);
#ifdef LTC_FAST
   for (x = 0; x < pmac->block_len; x += sizeof(LTC_FAST_TYPE)) {
       *(LTC_FAST_TYPE_PTR_CAST((unsigned char *)pmac->Li + x)) ^=
       *(LTC_FAST_TYPE_PTR_CAST((unsigned char *)pmac->Ls[y] + x));
   }
#else
   for (x = 0; x < pmac->block_len; x++) {
       pmac->Li[x] ^= pmac->Ls[y][x];
   }
#endif
}

#endif

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