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annotate libtommath/bn_mp_to_radix.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:
rev   line source
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_TO_RADIX_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 /* stores a bignum as a ASCII string in a given radix (2..64)
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7 *
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8 * Stores upto "size - 1" chars and always a NULL byte, puts the number of characters
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9 * written, including the '\0', in "written".
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10 */
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11 mp_err mp_to_radix(const mp_int *a, char *str, size_t maxlen, size_t *written, int radix)
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12 {
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13 size_t digs;
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14 mp_err err;
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15 mp_int t;
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16 mp_digit d;
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17 char *_s = str;
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18
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19 /* check range of radix and size*/
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20 if (maxlen < 2u) {
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21 return MP_BUF;
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22 }
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23 if ((radix < 2) || (radix > 64)) {
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24 return MP_VAL;
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25 }
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26
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27 /* quick out if its zero */
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28 if (MP_IS_ZERO(a)) {
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29 *str++ = '0';
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30 *str = '\0';
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31 if (written != NULL) {
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32 *written = 2u;
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33 }
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34 return MP_OKAY;
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35 }
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36
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37 if ((err = mp_init_copy(&t, a)) != MP_OKAY) {
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38 return err;
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39 }
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40
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41 /* if it is negative output a - */
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42 if (t.sign == MP_NEG) {
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43 /* we have to reverse our digits later... but not the - sign!! */
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44 ++_s;
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45
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46 /* store the flag and mark the number as positive */
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47 *str++ = '-';
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48 t.sign = MP_ZPOS;
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49
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50 /* subtract a char */
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51 --maxlen;
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52 }
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53 digs = 0u;
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54 while (!MP_IS_ZERO(&t)) {
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55 if (--maxlen < 1u) {
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56 /* no more room */
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57 err = MP_BUF;
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58 goto LBL_ERR;
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59 }
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60 if ((err = mp_div_d(&t, (mp_digit)radix, &t, &d)) != MP_OKAY) {
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61 goto LBL_ERR;
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62 }
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63 *str++ = mp_s_rmap[d];
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64 ++digs;
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65 }
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66 /* reverse the digits of the string. In this case _s points
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67 * to the first digit [exluding the sign] of the number
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68 */
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69 s_mp_reverse((unsigned char *)_s, digs);
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70
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71 /* append a NULL so the string is properly terminated */
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72 *str = '\0';
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73 digs++;
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74
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75 if (written != NULL) {
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76 *written = (a->sign == MP_NEG) ? (digs + 1u): digs;
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77 }
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78
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79 LBL_ERR:
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80 mp_clear(&t);
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81 return err;
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82 }
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83
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84 #endif