view libtomcrypt/src/pk/asn1/der/sequence/der_encode_sequence_multi.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"
#include <stdarg.h>


/**
  @file der_encode_sequence_multi.c
  ASN.1 DER, encode a SEQUENCE, Tom St Denis
*/

#ifdef LTC_DER

/**
  Encode a SEQUENCE type using a VA list
  @param out    [out] Destination for data
  @param outlen [in/out] Length of buffer and resulting length of output
  @remark <...> is of the form <type, size, data> (int, unsigned long, void*)
  @return CRYPT_OK on success
*/
int der_encode_sequence_multi(unsigned char *out, unsigned long *outlen, ...)
{
   int           err;
   ltc_asn1_type type;
   unsigned long size, x;
   void          *data;
   va_list       args;
   ltc_asn1_list *list;

   LTC_ARGCHK(out    != NULL);
   LTC_ARGCHK(outlen != NULL);

   /* get size of output that will be required */
   va_start(args, outlen);
   x = 0;
   for (;;) {
       type = (ltc_asn1_type)va_arg(args, int);
       size = va_arg(args, unsigned long);
       data = va_arg(args, void*);
       LTC_UNUSED_PARAM(size);
       LTC_UNUSED_PARAM(data);

       if (type == LTC_ASN1_EOL) {
          break;
       }

       switch (type) {
           case LTC_ASN1_BOOLEAN:
           case LTC_ASN1_INTEGER:
           case LTC_ASN1_SHORT_INTEGER:
           case LTC_ASN1_BIT_STRING:
           case LTC_ASN1_OCTET_STRING:
           case LTC_ASN1_NULL:
           case LTC_ASN1_OBJECT_IDENTIFIER:
           case LTC_ASN1_IA5_STRING:
           case LTC_ASN1_PRINTABLE_STRING:
           case LTC_ASN1_UTF8_STRING:
           case LTC_ASN1_UTCTIME:
           case LTC_ASN1_SEQUENCE:
           case LTC_ASN1_SET:
           case LTC_ASN1_SETOF:
           case LTC_ASN1_RAW_BIT_STRING:
           case LTC_ASN1_GENERALIZEDTIME:
                ++x;
                break;

           case LTC_ASN1_CHOICE:
           case LTC_ASN1_CONSTRUCTED:
           case LTC_ASN1_CONTEXT_SPECIFIC:
           case LTC_ASN1_EOL:
           case LTC_ASN1_TELETEX_STRING:
               va_end(args);
               return CRYPT_INVALID_ARG;
       }
   }
   va_end(args);

   /* allocate structure for x elements */
   if (x == 0) {
      return CRYPT_NOP;
   }

   list = XCALLOC(sizeof(*list), x);
   if (list == NULL) {
      return CRYPT_MEM;
   }

   /* fill in the structure */
   va_start(args, outlen);
   x = 0;
   for (;;) {
       type = (ltc_asn1_type)va_arg(args, int);
       size = va_arg(args, unsigned long);
       data = va_arg(args, void*);

       if (type == LTC_ASN1_EOL) {
          break;
       }

       switch (type) {
           case LTC_ASN1_BOOLEAN:
           case LTC_ASN1_INTEGER:
           case LTC_ASN1_SHORT_INTEGER:
           case LTC_ASN1_BIT_STRING:
           case LTC_ASN1_OCTET_STRING:
           case LTC_ASN1_NULL:
           case LTC_ASN1_OBJECT_IDENTIFIER:
           case LTC_ASN1_IA5_STRING:
           case LTC_ASN1_PRINTABLE_STRING:
           case LTC_ASN1_UTF8_STRING:
           case LTC_ASN1_UTCTIME:
           case LTC_ASN1_SEQUENCE:
           case LTC_ASN1_SET:
           case LTC_ASN1_SETOF:
           case LTC_ASN1_RAW_BIT_STRING:
           case LTC_ASN1_GENERALIZEDTIME:
                LTC_SET_ASN1(list, x++, type, data, size);
                break;

           case LTC_ASN1_CHOICE:
           case LTC_ASN1_CONSTRUCTED:
           case LTC_ASN1_CONTEXT_SPECIFIC:
           case LTC_ASN1_EOL:
           case LTC_ASN1_TELETEX_STRING:
               va_end(args);
               err = CRYPT_INVALID_ARG;
               goto LBL_ERR;
       }
   }
   va_end(args);

   err = der_encode_sequence(list, x, out, outlen);
LBL_ERR:
   XFREE(list);
   return err;
}

#endif


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