diff options
Diffstat (limited to 'crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/bn/bn_exp.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 44f47e7eb2..cc4528247e 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -106,7 +106,7 @@ BN_CTX *ctx; if (BN_is_odd(p)) { if (BN_copy(r,a) == NULL) goto err; } - else { if (BN_one(r)) goto err; } + else { if (!BN_one(r)) goto err; } for (i=1; i<bits; i++) { @@ -131,30 +131,35 @@ int BN_exp(r,a,p,ctx) BIGNUM *r,*a,*p; BN_CTX *ctx; { - int i,bits,ret=0; - BIGNUM *v,*tmp; + int i,bits,ret=0,tos; + BIGNUM *v,*rr; + tos=ctx->tos; v= &(ctx->bn[ctx->tos++]); - tmp= &(ctx->bn[ctx->tos++]); + if ((r == a) || (r == p)) + rr= &(ctx->bn[ctx->tos++]); + else + rr=r; if (BN_copy(v,a) == NULL) goto err; bits=BN_num_bits(p); if (BN_is_odd(p)) - { if (BN_copy(r,a) == NULL) goto err; } - else { if (BN_one(r)) goto err; } + { if (BN_copy(rr,a) == NULL) goto err; } + else { if (!BN_one(rr)) goto err; } for (i=1; i<bits; i++) { - if (!BN_sqr(tmp,v,ctx)) goto err; + if (!BN_sqr(v,v,ctx)) goto err; if (BN_is_bit_set(p,i)) { - if (!BN_mul(tmp,r,v,ctx)) goto err; + if (!BN_mul(rr,rr,v,ctx)) goto err; } } ret=1; err: - ctx->tos-=2; + ctx->tos=tos; + if (r != rr) BN_copy(r,rr); return(ret); } |