projects / packages / openssl.git / blame
| Commit | Line | Data |
|---|---|---|
| b4c9fbed AG |
1 | -----BEGIN PGP SIGNED MESSAGE----- |
| 2 | Hash: SHA1 | |
| 3 | ||
| 4 | - --- openssl-0.9.8e/crypto/bn/bn_mont.c 2006-06-16 03:01:14.000000000 +0200 | |
| 5 | +++ openssl-0.9.8-cvs/crypto/bn/bn_mont.c 2007-06-29 10:13:25.000000000 +0200 | |
| 6 | @@ -176,7 +176,6 @@ | |
| 7 | ||
| 8 | max=(nl+al+1); /* allow for overflow (no?) XXX */ | |
| 9 | if (bn_wexpand(r,max) == NULL) goto err; | |
| 10 | - - if (bn_wexpand(ret,max) == NULL) goto err; | |
| 11 | ||
| 12 | r->neg=a->neg^n->neg; | |
| 13 | np=n->d; | |
| 14 | @@ -228,19 +227,70 @@ | |
| 15 | } | |
| 16 | bn_correct_top(r); | |
| 17 | ||
| 18 | - - /* mont->ri will be a multiple of the word size */ | |
| 19 | - -#if 0 | |
| 20 | - - BN_rshift(ret,r,mont->ri); | |
| 21 | - -#else | |
| 22 | - - ret->neg = r->neg; | |
| 23 | - - x=ri; | |
| 24 | + /* mont->ri will be a multiple of the word size and below code | |
| 25 | + * is kind of BN_rshift(ret,r,mont->ri) equivalent */ | |
| 26 | + if (r->top <= ri) | |
| 27 | + { | |
| 28 | + ret->top=0; | |
| 29 | + retn=1; | |
| 30 | + goto err; | |
| 31 | + } | |
| 32 | + al=r->top-ri; | |
| 33 | + | |
| 34 | +# define BRANCH_FREE 1 | |
| 35 | +# if BRANCH_FREE | |
| 36 | + if (bn_wexpand(ret,ri) == NULL) goto err; | |
| 37 | + x=0-(((al-ri)>>(sizeof(al)*8-1))&1); | |
| 38 | + ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */ | |
| 39 | + ret->neg=r->neg; | |
| 40 | + | |
| 41 | rp=ret->d; | |
| 42 | - - ap= &(r->d[x]); | |
| 43 | - - if (r->top < x) | |
| 44 | - - al=0; | |
| 45 | - - else | |
| 46 | - - al=r->top-x; | |
| 47 | + ap=&(r->d[ri]); | |
| 48 | + | |
| 49 | + { | |
| 50 | + size_t m1,m2; | |
| 51 | + | |
| 52 | + v=bn_sub_words(rp,ap,np,ri); | |
| 53 | + /* this ----------------^^ works even in al<ri case | |
| 54 | + * thanks to zealous zeroing of top of the vector in the | |
| 55 | + * beginning. */ | |
| 56 | + | |
| 57 | + /* if (al==ri && !v) || al>ri) nrp=rp; else nrp=ap; */ | |
| 58 | + /* in other words if subtraction result is real, then | |
| 59 | + * trick unconditional memcpy below to perform in-place | |
| 60 | + * "refresh" instead of actual copy. */ | |
| 61 | + m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al<ri */ | |
| 62 | + m2=0-(size_t)(((ri-al)>>(sizeof(al)*8-1))&1); /* al>ri */ | |
| 63 | + m1|=m2; /* (al!=ri) */ | |
| 64 | + m1|=(0-(size_t)v); /* (al!=ri || v) */ | |
| 65 | + m1&=~m2; /* (al!=ri || v) && !al>ri */ | |
| 66 | + nrp=(BN_ULONG *)(((size_t)rp&~m1)|((size_t)ap&m1)); | |
| 67 | + } | |
| 68 | + | |
| 69 | + /* 'i<ri' is chosen to eliminate dependency on input data, even | |
| 70 | + * though it results in redundant copy in al<ri case. */ | |
| 71 | + for (i=0,ri-=4; i<ri; i+=4) | |
| 72 | + { | |
| 73 | + BN_ULONG t1,t2,t3,t4; | |
| 74 | + | |
| 75 | + t1=nrp[i+0]; | |
| 76 | + t2=nrp[i+1]; | |
| 77 | + t3=nrp[i+2]; ap[i+0]=0; | |
| 78 | + t4=nrp[i+3]; ap[i+1]=0; | |
| 79 | + rp[i+0]=t1; ap[i+2]=0; | |
| 80 | + rp[i+1]=t2; ap[i+3]=0; | |
| 81 | + rp[i+2]=t3; | |
| 82 | + rp[i+3]=t4; | |
| 83 | + } | |
| 84 | + for (ri+=4; i<ri; i++) | |
| 85 | + rp[i]=nrp[i], ap[i]=0; | |
| 86 | +# else | |
| 87 | + if (bn_wexpand(ret,al) == NULL) goto err; | |
| 88 | ret->top=al; | |
| 89 | + ret->neg=r->neg; | |
| 90 | + | |
| 91 | + rp=ret->d; | |
| 92 | + ap=&(r->d[ri]); | |
| 93 | al-=4; | |
| 94 | for (i=0; i<al; i+=4) | |
| 95 | { | |
| 96 | @@ -258,7 +308,7 @@ | |
| 97 | al+=4; | |
| 98 | for (; i<al; i++) | |
| 99 | rp[i]=ap[i]; | |
| 100 | - -#endif | |
| 101 | +# endif | |
| 102 | #else /* !MONT_WORD */ | |
| 103 | BIGNUM *t1,*t2; | |
| 104 | ||
| 105 | @@ -278,10 +328,12 @@ | |
| 106 | if (!BN_rshift(ret,t2,mont->ri)) goto err; | |
| 107 | #endif /* MONT_WORD */ | |
| 108 | ||
| 109 | +#if !defined(BRANCH_FREE) || BRANCH_FREE==0 | |
| 110 | if (BN_ucmp(ret, &(mont->N)) >= 0) | |
| 111 | { | |
| 112 | if (!BN_usub(ret,ret,&(mont->N))) goto err; | |
| 113 | } | |
| 114 | +#endif | |
| 115 | retn=1; | |
| 116 | bn_check_top(ret); | |
| 117 | err: | |
| 118 | -----BEGIN PGP SIGNATURE----- | |
| 119 | Version: GnuPG v1.4.5 (GNU/Linux) | |
| 120 | ||
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| 124 | iBDdynBpa+s= | |
| 125 | =aquq | |
| 126 | -----END PGP SIGNATURE----- |