Mercurial > dropbear
annotate libtommath/bn_mp_rshd.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> |
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date | Mon, 09 Jul 2018 16:27:53 +0200 |
parents | 1051e4eea25a |
children |
rev | line source |
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update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
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1 #include "tommath_private.h" |
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2 #ifdef BN_MP_RSHD_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 /* shift right a certain amount of digits */ |
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7 void mp_rshd(mp_int *a, int b) |
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8 { |
1655
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parents:
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9 int x; |
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10 mp_digit *bottom, *top; |
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11 |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
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12 /* if b <= 0 then ignore it */ |
f52919ffd3b1
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parents:
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13 if (b <= 0) { |
f52919ffd3b1
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14 return; |
f52919ffd3b1
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15 } |
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16 |
1655
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17 /* if b > used then simply zero it and return */ |
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
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18 if (a->used <= b) { |
f52919ffd3b1
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parents:
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19 mp_zero(a); |
f52919ffd3b1
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parents:
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20 return; |
f52919ffd3b1
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21 } |
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22 |
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23 /* shift the digits down */ |
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24 |
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25 /* bottom */ |
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26 bottom = a->dp; |
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27 |
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28 /* top [offset into digits] */ |
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29 top = a->dp + b; |
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30 |
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31 /* this is implemented as a sliding window where |
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32 * the window is b-digits long and digits from |
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33 * the top of the window are copied to the bottom |
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34 * |
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35 * e.g. |
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36 |
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37 b-2 | b-1 | b0 | b1 | b2 | ... | bb | ----> |
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38 /\ | ----> |
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39 \-------------------/ ----> |
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40 */ |
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41 for (x = 0; x < (a->used - b); x++) { |
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42 *bottom++ = *top++; |
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43 } |
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44 |
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45 /* zero the top digits */ |
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46 MP_ZERO_DIGITS(bottom, a->used - x); |
1655
f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents:
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47 |
f52919ffd3b1
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parents:
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48 /* remove excess digits */ |
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49 a->used -= b; |
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50 } |
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51 #endif |