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annotate libtommath/bn_mp_unpack.c @ 1930:299f4f19ba19

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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 1051e4eea25a
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1692
1051e4eea25a Update LibTomMath to 1.2.0 (#84)
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1 #include "tommath_private.h"
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2 #ifdef BN_MP_UNPACK_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
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4 /* SPDX-License-Identifier: Unlicense */
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5
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6 /* based on gmp's mpz_import.
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7 * see http://gmplib.org/manual/Integer-Import-and-Export.html
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8 */
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9 mp_err mp_unpack(mp_int *rop, size_t count, mp_order order, size_t size,
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10 mp_endian endian, size_t nails, const void *op)
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11 {
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12 mp_err err;
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13 size_t odd_nails, nail_bytes, i, j;
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14 unsigned char odd_nail_mask;
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15
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16 mp_zero(rop);
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17
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18 if (endian == MP_NATIVE_ENDIAN) {
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19 MP_GET_ENDIANNESS(endian);
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20 }
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21
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22 odd_nails = (nails % 8u);
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23 odd_nail_mask = 0xff;
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24 for (i = 0; i < odd_nails; ++i) {
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25 odd_nail_mask ^= (unsigned char)(1u << (7u - i));
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26 }
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27 nail_bytes = nails / 8u;
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28
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29 for (i = 0; i < count; ++i) {
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30 for (j = 0; j < (size - nail_bytes); ++j) {
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31 unsigned char byte = *((const unsigned char *)op +
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32 (((order == MP_MSB_FIRST) ? i : ((count - 1u) - i)) * size) +
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33 ((endian == MP_BIG_ENDIAN) ? (j + nail_bytes) : (((size - 1u) - j) - nail_bytes)));
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34
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35 if ((err = mp_mul_2d(rop, (j == 0u) ? (int)(8u - odd_nails) : 8, rop)) != MP_OKAY) {
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36 return err;
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37 }
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38
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39 rop->dp[0] |= (j == 0u) ? (mp_digit)(byte & odd_nail_mask) : (mp_digit)byte;
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40 rop->used += 1;
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41 }
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42 }
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43
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44 mp_clamp(rop);
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45
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46 return MP_OKAY;
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47 }
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48
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49 #endif