Mercurial > dropbear
view libtomcrypt/src/pk/ecc/ltc_ecc_projective_add_point.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. */ /* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b * * All curves taken from NIST recommendation paper of July 1999 * Available at http://csrc.nist.gov/cryptval/dss.htm */ #include "tomcrypt.h" /** @file ltc_ecc_projective_add_point.c ECC Crypto, Tom St Denis */ #if defined(LTC_MECC) && (!defined(LTC_MECC_ACCEL) || defined(LTM_DESC)) /** Add two ECC points @param P The point to add @param Q The point to add @param R [out] The destination of the double @param modulus The modulus of the field the ECC curve is in @param mp The "b" value from montgomery_setup() @return CRYPT_OK on success */ int ltc_ecc_projective_add_point(ecc_point *P, ecc_point *Q, ecc_point *R, void *modulus, void *mp) { void *t1, *t2, *x, *y, *z; int err; LTC_ARGCHK(P != NULL); LTC_ARGCHK(Q != NULL); LTC_ARGCHK(R != NULL); LTC_ARGCHK(modulus != NULL); LTC_ARGCHK(mp != NULL); if ((err = mp_init_multi(&t1, &t2, &x, &y, &z, NULL)) != CRYPT_OK) { return err; } /* should we dbl instead? */ if ((err = mp_sub(modulus, Q->y, t1)) != CRYPT_OK) { goto done; } if ( (mp_cmp(P->x, Q->x) == LTC_MP_EQ) && (Q->z != NULL && mp_cmp(P->z, Q->z) == LTC_MP_EQ) && (mp_cmp(P->y, Q->y) == LTC_MP_EQ || mp_cmp(P->y, t1) == LTC_MP_EQ)) { mp_clear_multi(t1, t2, x, y, z, NULL); return ltc_ecc_projective_dbl_point(P, R, modulus, mp); } if ((err = mp_copy(P->x, x)) != CRYPT_OK) { goto done; } if ((err = mp_copy(P->y, y)) != CRYPT_OK) { goto done; } if ((err = mp_copy(P->z, z)) != CRYPT_OK) { goto done; } /* if Z is one then these are no-operations */ if (Q->z != NULL) { /* T1 = Z' * Z' */ if ((err = mp_sqr(Q->z, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* X = X * T1 */ if ((err = mp_mul(t1, x, x)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; } /* T1 = Z' * T1 */ if ((err = mp_mul(Q->z, t1, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* Y = Y * T1 */ if ((err = mp_mul(t1, y, y)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(y, modulus, mp)) != CRYPT_OK) { goto done; } } /* T1 = Z*Z */ if ((err = mp_sqr(z, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* T2 = X' * T1 */ if ((err = mp_mul(Q->x, t1, t2)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; } /* T1 = Z * T1 */ if ((err = mp_mul(z, t1, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* T1 = Y' * T1 */ if ((err = mp_mul(Q->y, t1, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* Y = Y - T1 */ if ((err = mp_sub(y, t1, y)) != CRYPT_OK) { goto done; } if (mp_cmp_d(y, 0) == LTC_MP_LT) { if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; } } /* T1 = 2T1 */ if ((err = mp_add(t1, t1, t1)) != CRYPT_OK) { goto done; } if (mp_cmp(t1, modulus) != LTC_MP_LT) { if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; } } /* T1 = Y + T1 */ if ((err = mp_add(t1, y, t1)) != CRYPT_OK) { goto done; } if (mp_cmp(t1, modulus) != LTC_MP_LT) { if ((err = mp_sub(t1, modulus, t1)) != CRYPT_OK) { goto done; } } /* X = X - T2 */ if ((err = mp_sub(x, t2, x)) != CRYPT_OK) { goto done; } if (mp_cmp_d(x, 0) == LTC_MP_LT) { if ((err = mp_add(x, modulus, x)) != CRYPT_OK) { goto done; } } /* T2 = 2T2 */ if ((err = mp_add(t2, t2, t2)) != CRYPT_OK) { goto done; } if (mp_cmp(t2, modulus) != LTC_MP_LT) { if ((err = mp_sub(t2, modulus, t2)) != CRYPT_OK) { goto done; } } /* T2 = X + T2 */ if ((err = mp_add(t2, x, t2)) != CRYPT_OK) { goto done; } if (mp_cmp(t2, modulus) != LTC_MP_LT) { if ((err = mp_sub(t2, modulus, t2)) != CRYPT_OK) { goto done; } } /* if Z' != 1 */ if (Q->z != NULL) { /* Z = Z * Z' */ if ((err = mp_mul(z, Q->z, z)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(z, modulus, mp)) != CRYPT_OK) { goto done; } } /* Z = Z * X */ if ((err = mp_mul(z, x, z)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(z, modulus, mp)) != CRYPT_OK) { goto done; } /* T1 = T1 * X */ if ((err = mp_mul(t1, x, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* X = X * X */ if ((err = mp_sqr(x, x)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; } /* T2 = T2 * x */ if ((err = mp_mul(t2, x, t2)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; } /* T1 = T1 * X */ if ((err = mp_mul(t1, x, t1)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t1, modulus, mp)) != CRYPT_OK) { goto done; } /* X = Y*Y */ if ((err = mp_sqr(y, x)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(x, modulus, mp)) != CRYPT_OK) { goto done; } /* X = X - T2 */ if ((err = mp_sub(x, t2, x)) != CRYPT_OK) { goto done; } if (mp_cmp_d(x, 0) == LTC_MP_LT) { if ((err = mp_add(x, modulus, x)) != CRYPT_OK) { goto done; } } /* T2 = T2 - X */ if ((err = mp_sub(t2, x, t2)) != CRYPT_OK) { goto done; } if (mp_cmp_d(t2, 0) == LTC_MP_LT) { if ((err = mp_add(t2, modulus, t2)) != CRYPT_OK) { goto done; } } /* T2 = T2 - X */ if ((err = mp_sub(t2, x, t2)) != CRYPT_OK) { goto done; } if (mp_cmp_d(t2, 0) == LTC_MP_LT) { if ((err = mp_add(t2, modulus, t2)) != CRYPT_OK) { goto done; } } /* T2 = T2 * Y */ if ((err = mp_mul(t2, y, t2)) != CRYPT_OK) { goto done; } if ((err = mp_montgomery_reduce(t2, modulus, mp)) != CRYPT_OK) { goto done; } /* Y = T2 - T1 */ if ((err = mp_sub(t2, t1, y)) != CRYPT_OK) { goto done; } if (mp_cmp_d(y, 0) == LTC_MP_LT) { if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; } } /* Y = Y/2 */ if (mp_isodd(y)) { if ((err = mp_add(y, modulus, y)) != CRYPT_OK) { goto done; } } if ((err = mp_div_2(y, y)) != CRYPT_OK) { goto done; } if ((err = mp_copy(x, R->x)) != CRYPT_OK) { goto done; } if ((err = mp_copy(y, R->y)) != CRYPT_OK) { goto done; } if ((err = mp_copy(z, R->z)) != CRYPT_OK) { goto done; } err = CRYPT_OK; done: mp_clear_multi(t1, t2, x, y, z, NULL); return err; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */