Mercurial > dropbear
view libtommath/bn_mp_expt_u32.c @ 1705:5b701bf529aa
Fix ChaCha20 on 32-bit platforms (#99)
* Fix ChaCha20 on 32-bit platforms
On 32-bit platforms with old compiler STORE64H() parameter is
not auto-expanded to 64-bit value, causing wrong IV data.
Spotted on BCM4706 MIPS32r2 with GCC 4.2.4:
Exit before auth: Integrity error (bad packet size 2065808956)
* Fix Chacha20-Poly1305 and AES-GCM debug messages
Functions were renamed earlier and trace messages - not.
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
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date | Fri, 29 May 2020 18:26:22 +0500 |
parents | 1051e4eea25a |
children |
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#include "tommath_private.h" #ifdef BN_MP_EXPT_U32_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* calculate c = a**b using a square-multiply algorithm */ mp_err mp_expt_u32(const mp_int *a, uint32_t b, mp_int *c) { mp_err err; mp_int g; if ((err = mp_init_copy(&g, a)) != MP_OKAY) { return err; } /* set initial result */ mp_set(c, 1uL); while (b > 0u) { /* if the bit is set multiply */ if ((b & 1u) != 0u) { if ((err = mp_mul(c, &g, c)) != MP_OKAY) { goto LBL_ERR; } } /* square */ if (b > 1u) { if ((err = mp_sqr(&g, &g)) != MP_OKAY) { goto LBL_ERR; } } /* shift to next bit */ b >>= 1; } err = MP_OKAY; LBL_ERR: mp_clear(&g); return err; } #endif