view libtomcrypt/src/mac/blake2/blake2bmac.c @ 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: 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
author Raphael Hertzog <hertzog@debian.org>
date Mon, 09 Jul 2018 16:27:53 +0200
parents 6dba84798cd5
children
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/* 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"

#ifdef LTC_BLAKE2BMAC

/**
   Initialize an BLAKE2B MAC context.
   @param st       The BLAKE2B MAC state
   @param outlen   The size of the MAC output (octets)
   @param key      The secret key
   @param keylen   The length of the secret key (octets)
   @return CRYPT_OK if successful
*/
int blake2bmac_init(blake2bmac_state *st, unsigned long outlen, const unsigned char *key, unsigned long keylen)
{
   LTC_ARGCHK(st  != NULL);
   LTC_ARGCHK(key != NULL);
   return blake2b_init(st, outlen, key, keylen);
}

/**
  Process data through BLAKE2B MAC
  @param st      The BLAKE2B MAC state
  @param in      The data to send through HMAC
  @param inlen   The length of the data to HMAC (octets)
  @return CRYPT_OK if successful
*/
int blake2bmac_process(blake2bmac_state *st, const unsigned char *in, unsigned long inlen)
{
   if (inlen == 0) return CRYPT_OK; /* nothing to do */
   LTC_ARGCHK(st != NULL);
   LTC_ARGCHK(in != NULL);
   return blake2b_process(st, in, inlen);
}

/**
   Terminate a BLAKE2B MAC session
   @param st      The BLAKE2B MAC state
   @param mac     [out] The destination of the BLAKE2B MAC authentication tag
   @param maclen  [in/out]  The max size and resulting size of the BLAKE2B MAC authentication tag
   @return CRYPT_OK if successful
*/
int blake2bmac_done(blake2bmac_state *st, unsigned char *mac, unsigned long *maclen)
{
   LTC_ARGCHK(st     != NULL);
   LTC_ARGCHK(mac    != NULL);
   LTC_ARGCHK(maclen != NULL);
   LTC_ARGCHK(*maclen >= st->blake2b.outlen);

   *maclen = st->blake2b.outlen;
   return blake2b_done(st, mac);
}

#endif

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