view libtomcrypt/src/encauth/ocb3/ocb3_encrypt_authenticate_memory.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
line wrap: on
line source

/* 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.
 */

/**
  @file ocb3_encrypt_authenticate_memory.c
  OCB implementation, encrypt block of memory, by Tom St Denis
*/
#include "tomcrypt.h"

#ifdef LTC_OCB3_MODE

/**
   Encrypt and generate an authentication code for a buffer of memory
   @param cipher     The index of the cipher desired
   @param key        The secret key
   @param keylen     The length of the secret key (octets)
   @param nonce      The session nonce (length of the block ciphers block size)
   @param noncelen   The length of the nonce (octets)
   @param adata      The AAD - additional associated data
   @param adatalen   The length of AAD (octets)
   @param pt         The plaintext
   @param ptlen      The length of the plaintext (octets)
   @param ct         [out] The ciphertext
   @param tag        [out] The authentication tag
   @param taglen     [in/out] The max size and resulting size of the authentication tag
   @return CRYPT_OK if successful
*/
int ocb3_encrypt_authenticate_memory(int cipher,
    const unsigned char *key,    unsigned long keylen,
    const unsigned char *nonce,  unsigned long noncelen,
    const unsigned char *adata,  unsigned long adatalen,
    const unsigned char *pt,     unsigned long ptlen,
          unsigned char *ct,
          unsigned char *tag,    unsigned long *taglen)
{
   int err;
   ocb3_state *ocb;

   LTC_ARGCHK(taglen != NULL);

   /* allocate memory */
   ocb = XMALLOC(sizeof(ocb3_state));
   if (ocb == NULL) {
      return CRYPT_MEM;
   }

   if ((err = ocb3_init(ocb, cipher, key, keylen, nonce, noncelen, *taglen)) != CRYPT_OK) {
      goto LBL_ERR;
   }

   if (adata != NULL || adatalen != 0) {
      if ((err = ocb3_add_aad(ocb, adata, adatalen)) != CRYPT_OK) {
         goto LBL_ERR;
      }
   }

   if ((err = ocb3_encrypt_last(ocb, pt, ptlen, ct)) != CRYPT_OK) {
      goto LBL_ERR;
   }

   err = ocb3_done(ocb, tag, taglen);

LBL_ERR:
#ifdef LTC_CLEAN_STACK
   zeromem(ocb, sizeof(ocb3_state));
#endif

   XFREE(ocb);
   return err;
}

#endif

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */