7d83ff16f8
Combined commits between 0.15 and 0.19: - Decoupled -DARCH_X86_64 and support_rdrand - add an untested workaround for i686 machine - limit to i686 and x86_64 - add possible workaround for fPIC building - re-use standard instruction
127 lines
4.0 KiB
C
127 lines
4.0 KiB
C
/*
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* Copyright (C) Thomas DuBuisson
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* Copyright (C) 2013 Vincent Hanquez <tab@snarc.org>
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of his contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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int cryptonite_cpu_has_rdrand()
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{
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uint32_t ax,bx,cx,dx,func=1;
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#if defined(__PIC__) && defined(__i386__)
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__asm__ volatile ("mov %%ebx, %%edi;" "cpuid;" "xchgl %%ebx, %%edi;"
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: "=a" (ax), "=D" (bx), "=c" (cx), "=d" (dx) : "a" (func));
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#else
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__asm__ volatile ("cpuid": "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));
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#endif
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return (cx & 0x40000000);
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}
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/* inline encoding of 'rdrand %rax' to cover old binutils
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* - no inputs
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* - 'cc' to the clobber list as we modify condition code.
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* - output of rdrand in rax and have a 8 bit error condition
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*/
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#define inline_rdrand_rax(val, err) \
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asm(".byte 0x48,0x0f,0xc7,0xf0; setc %1" \
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: "=a" (val), "=q" (err) \
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: \
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: "cc")
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/* inline encoding of 'rdrand %eax' to cover old binutils
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* - no inputs
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* - 'cc' to the clobber list as we modify condition code.
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* - output of rdrand in eax and have a 8 bit error condition
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*/
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#define inline_rdrand_eax(val, err) \
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asm(".byte 0x0f,0xc7,0xf0; setc %1" \
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: "=a" (val), "=q" (err) \
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: \
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: "cc")
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#ifdef __x86_64__
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# define RDRAND_SZ 8
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# define RDRAND_T uint64_t
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#define inline_rdrand(val, err) err = cryptonite_rdrand_step(&val)
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#else
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# define RDRAND_SZ 4
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# define RDRAND_T uint32_t
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#define inline_rdrand(val, err) err = cryptonite_rdrand_step(&val)
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#endif
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/* sadly many people are still using an old binutils,
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* leading to report that instruction is not recognized.
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*/
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#if 1
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/* Returns 1 on success */
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static inline int cryptonite_rdrand_step(RDRAND_T *buffer)
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{
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unsigned char err;
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asm volatile ("rdrand %0; setc %1" : "=r" (*buffer), "=qm" (err));
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return (int) err;
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}
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#endif
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/* Returns the number of bytes succesfully generated */
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int cryptonite_get_rand_bytes(uint8_t *buffer, size_t len)
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{
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RDRAND_T tmp;
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int aligned = (intptr_t) buffer % RDRAND_SZ;
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int orig_len = len;
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int to_alignment = RDRAND_SZ - aligned;
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uint8_t ok;
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if (aligned != 0) {
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inline_rdrand(tmp, ok);
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if (!ok)
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return 0;
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memcpy(buffer, (uint8_t *) &tmp, to_alignment);
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buffer += to_alignment;
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len -= to_alignment;
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}
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for (; len >= RDRAND_SZ; buffer += RDRAND_SZ, len -= RDRAND_SZ) {
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inline_rdrand(tmp, ok);
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if (!ok)
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return (orig_len - len);
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*((RDRAND_T *) buffer) = tmp;
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}
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if (len > 0) {
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inline_rdrand(tmp, ok);
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if (!ok)
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return (orig_len - len);
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memcpy(buffer, (uint8_t *) &tmp, len);
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}
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return orig_len;
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}
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