haskell/cryptonite
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rdrand-related code and build flag changes

Browse Source 
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
This commit is contained in:
John Galt 2016-04-21 10:45:23 -07:00 committed by Luke Taylor
parent ab3ca7b5df
commit 7d83ff16f8
2 changed files with 51 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
cbits/cryptonite_rdrand.c
View File

@ -37,23 +37,15 @@
int cryptonite_cpu_has_rdrand()
{
uint32_t ax,bx,cx,dx,func=1;
#if defined(__PIC__) && defined(__i386__)
__asm__ volatile ("mov %%ebx, %%edi;" "cpuid;" "xchgl %%ebx, %%edi;"
: "=a" (ax), "=D" (bx), "=c" (cx), "=d" (dx) : "a" (func));
#else
__asm__ volatile ("cpuid": "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));
#endif
return (cx & 0x40000000);
}
/* sadly many people are still using an old binutils,
* leading to report that instruction is not recognized.
*/
#if 0
/* Returns 1 on success */
static inline int crypto_random_rdrand64_step(uint64_t *buffer)
{
unsigned char err;
asm volatile ("rdrand %0; setc %1" : "=r" (*buffer), "=qm" (err));
return (int) err;
}
#endif
/* inline encoding of 'rdrand %rax' to cover old binutils
* - no inputs
* - 'cc' to the clobber list as we modify condition code.
@ -65,17 +57,51 @@ static inline int crypto_random_rdrand64_step(uint64_t *buffer)
: \
: "cc")
/* inline encoding of 'rdrand %eax' to cover old binutils
* - no inputs
* - 'cc' to the clobber list as we modify condition code.
* - output of rdrand in eax and have a 8 bit error condition
*/
#define inline_rdrand_eax(val, err) \
asm(".byte 0x0f,0xc7,0xf0; setc %1" \
: "=a" (val), "=q" (err) \
: \
: "cc")
#ifdef __x86_64__
# define RDRAND_SZ 8
# define RDRAND_T uint64_t
#define inline_rdrand(val, err) err = cryptonite_rdrand_step(&val)
#else
# define RDRAND_SZ 4
# define RDRAND_T uint32_t
#define inline_rdrand(val, err) err = cryptonite_rdrand_step(&val)
#endif
/* sadly many people are still using an old binutils,
* leading to report that instruction is not recognized.
*/
#if 1
/* Returns 1 on success */
static inline int cryptonite_rdrand_step(RDRAND_T *buffer)
{
unsigned char err;
asm volatile ("rdrand %0; setc %1" : "=r" (*buffer), "=qm" (err));
return (int) err;
}
#endif
/* Returns the number of bytes succesfully generated */
int cryptonite_get_rand_bytes(uint8_t *buffer, size_t len)
{
uint64_t tmp;
int aligned = (intptr_t) buffer % 8;
RDRAND_T tmp;
int aligned = (intptr_t) buffer % RDRAND_SZ;
int orig_len = len;
int to_alignment = 8 - aligned;
int to_alignment = RDRAND_SZ - aligned;
uint8_t ok;
if (aligned != 0) {
inline_rdrand_rax(tmp, ok);
inline_rdrand(tmp, ok);
if (!ok)
return 0;
memcpy(buffer, (uint8_t *) &tmp, to_alignment);
@ -83,15 +109,15 @@ int cryptonite_get_rand_bytes(uint8_t *buffer, size_t len)
len -= to_alignment;
}
for (; len >= 8; buffer += 8, len -= 8) {
inline_rdrand_rax(tmp, ok);
for (; len >= RDRAND_SZ; buffer += RDRAND_SZ, len -= RDRAND_SZ) {
inline_rdrand(tmp, ok);
if (!ok)
return (orig_len - len);
*((uint64_t *) buffer) = tmp;
*((RDRAND_T *) buffer) = tmp;
}
if (len > 0) {
inline_rdrand_rax(tmp, ok);
inline_rdrand(tmp, ok);
if (!ok)
return (orig_len - len);
memcpy(buffer, (uint8_t *) &tmp, len);

6
cryptonite.cabal
View File

@ -236,8 +236,10 @@ Library
if arch(i386)
CPP-options: -DARCH_X86
if flag(support_rdrand) && arch(x86_64)
CPP-options: -DARCH_X86_64
if arch(x86_64)
CPP-options: -DARCH_X86_64
if flag(support_rdrand) && (arch(i386) || arch(x86_64))
CPP-options: -DSUPPORT_RDRAND
Other-modules: Crypto.Random.Entropy.RDRand
c-sources: cbits/cryptonite_rdrand.c