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openssl/openssl-0.9.8b-cve-2007-3108.patch
Tomáš Mráz aa64c417f5 - use localhost in testsuite, hopefully fixes slow build in koji 
- CVE-2007-3108 - fix side channel attack on private keys (#250577)
- make ssl session cache id matching strict (#233599)
2007-08-03 12:16:54 +00:00

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diff -up openssl-0.9.8b/crypto/rsa/rsa.h.no-branch openssl-0.9.8b/crypto/rsa/rsa.h
--- openssl-0.9.8b/crypto/rsa/rsa.h.no-branch 2007-08-03 13:58:54.000000000 +0200
+++ openssl-0.9.8b/crypto/rsa/rsa.h 2007-08-03 13:58:58.000000000 +0200
@@ -189,13 +189,17 @@ struct rsa_st
* default (ignoring RSA_FLAG_BLINDING),
* but other engines might not need it
*/
-#define RSA_FLAG_NO_EXP_CONSTTIME 0x0100 /* new with 0.9.7h; the built-in RSA
- * implementation now uses constant time
- * modular exponentiation for secret exponents
- * by default. This flag causes the
- * faster variable sliding window method to
- * be used for all exponents.
- */
+#define RSA_FLAG_NO_CONSTTIME 0x0100 /* new with 0.9.8f; the built-in RSA
+ * implementation now uses constant time
+ * operations by default in private key operations,
+ * e.g., constant time modular exponentiation,
+ * modular inverse without leaking branches,
+ * division without leaking branches. This
+ * flag disables these constant time
+ * operations and results in faster RSA
+ * private key operations.
+ */
+#define RSA_FLAG_NO_EXP_CONSTTIME RSA_FLAG_NO_CONSTTIME /* deprecated name for the flag*/
#define RSA_PKCS1_PADDING 1
#define RSA_SSLV23_PADDING 2
diff -up openssl-0.9.8b/crypto/rsa/rsa_lib.c.no-branch openssl-0.9.8b/crypto/rsa/rsa_lib.c
--- openssl-0.9.8b/crypto/rsa/rsa_lib.c.no-branch 2005-11-25 15:26:12.000000000 +0100
+++ openssl-0.9.8b/crypto/rsa/rsa_lib.c 2007-08-03 13:58:58.000000000 +0200
@@ -361,7 +361,8 @@ err:
BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
{
- BIGNUM *e;
+ BIGNUM local_n;
+ BIGNUM *e,*n;
BN_CTX *ctx;
BN_BLINDING *ret = NULL;
@@ -400,7 +401,16 @@ BN_BLINDING *RSA_setup_blinding(RSA *rsa
RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
}
- ret = BN_BLINDING_create_param(NULL, e, rsa->n, ctx,
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ /* Set BN_FLG_CONSTTIME flag */
+ n = &local_n;
+ BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
+ }
+ else
+ n = rsa->n;
+
+ ret = BN_BLINDING_create_param(NULL, e, n, ctx,
rsa->meth->bn_mod_exp, rsa->_method_mod_n);
if (ret == NULL)
{
diff -up openssl-0.9.8b/crypto/rsa/rsa_gen.c.no-branch openssl-0.9.8b/crypto/rsa/rsa_gen.c
--- openssl-0.9.8b/crypto/rsa/rsa_gen.c.no-branch 2006-03-14 00:12:08.000000000 +0100
+++ openssl-0.9.8b/crypto/rsa/rsa_gen.c 2007-08-03 13:58:58.000000000 +0200
@@ -85,6 +85,8 @@ int RSA_generate_key_ex(RSA *rsa, int bi
static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
{
BIGNUM *r0=NULL,*r1=NULL,*r2=NULL,*r3=NULL,*tmp;
+ BIGNUM local_r0,local_d,local_p;
+ BIGNUM *pr0,*d,*p;
int bitsp,bitsq,ok= -1,n=0;
BN_CTX *ctx=NULL;
@@ -165,16 +167,39 @@ static int rsa_builtin_keygen(RSA *rsa,
if (!BN_sub(r1,rsa->p,BN_value_one())) goto err; /* p-1 */
if (!BN_sub(r2,rsa->q,BN_value_one())) goto err; /* q-1 */
if (!BN_mul(r0,r1,r2,ctx)) goto err; /* (p-1)(q-1) */
- if (!BN_mod_inverse(rsa->d,rsa->e,r0,ctx)) goto err; /* d */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ pr0 = &local_r0;
+ BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
+ }
+ else
+ pr0 = r0;
+ if (!BN_mod_inverse(rsa->d,rsa->e,pr0,ctx)) goto err; /* d */
+
+ /* set up d for correct BN_FLG_CONSTTIME flag */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ d = &local_d;
+ BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
+ }
+ else
+ d = rsa->d;
/* calculate d mod (p-1) */
- if (!BN_mod(rsa->dmp1,rsa->d,r1,ctx)) goto err;
+ if (!BN_mod(rsa->dmp1,d,r1,ctx)) goto err;
/* calculate d mod (q-1) */
- if (!BN_mod(rsa->dmq1,rsa->d,r2,ctx)) goto err;
+ if (!BN_mod(rsa->dmq1,d,r2,ctx)) goto err;
/* calculate inverse of q mod p */
- if (!BN_mod_inverse(rsa->iqmp,rsa->q,rsa->p,ctx)) goto err;
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ p = &local_p;
+ BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
+ }
+ else
+ p = rsa->p;
+ if (!BN_mod_inverse(rsa->iqmp,rsa->q,p,ctx)) goto err;
ok=1;
err:
diff -up openssl-0.9.8b/crypto/rsa/rsa_eay.c.no-branch openssl-0.9.8b/crypto/rsa/rsa_eay.c
--- openssl-0.9.8b/crypto/rsa/rsa_eay.c.no-branch 2007-08-03 13:58:54.000000000 +0200
+++ openssl-0.9.8b/crypto/rsa/rsa_eay.c 2007-08-03 13:58:58.000000000 +0200
@@ -429,11 +429,11 @@ static int RSA_eay_private_encrypt(int f
BIGNUM local_d;
BIGNUM *d = NULL;
- if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
{
BN_init(&local_d);
d = &local_d;
- BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+ BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
}
else
d = rsa->d;
@@ -551,10 +551,10 @@ static int RSA_eay_private_decrypt(int f
BIGNUM local_d;
BIGNUM *d = NULL;
- if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
{
d = &local_d;
- BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+ BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
}
else
d = rsa->d;
@@ -724,8 +724,9 @@ err:
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
{
BIGNUM *r1,*m1,*vrfy;
- BIGNUM local_dmp1, local_dmq1;
- BIGNUM *dmp1, *dmq1;
+ BIGNUM local_dmp1,local_dmq1,local_c,local_r1;
+ BIGNUM *dmp1,*dmq1,*c,*pr1;
+ int bn_flags;
int ret=0;
BN_CTX_start(ctx);
@@ -733,26 +734,72 @@ static int RSA_eay_mod_exp(BIGNUM *r0, c
m1 = BN_CTX_get(ctx);
vrfy = BN_CTX_get(ctx);
+ /* Make sure mod_inverse in montgomerey intialization use correct
+ * BN_FLG_CONSTTIME flag.
+ */
+ bn_flags = rsa->p->flags;
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ rsa->p->flags |= BN_FLG_CONSTTIME;
+ }
MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
+ /* We restore bn_flags back */
+ rsa->p->flags = bn_flags;
+
+ /* Make sure mod_inverse in montgomerey intialization use correct
+ * BN_FLG_CONSTTIME flag.
+ */
+ bn_flags = rsa->q->flags;
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ rsa->q->flags |= BN_FLG_CONSTTIME;
+ }
MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
+ /* We restore bn_flags back */
+ rsa->q->flags = bn_flags;
+
MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
- if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
- if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+ /* compute I mod q */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ c = &local_c;
+ BN_with_flags(c, I, BN_FLG_CONSTTIME);
+ if (!BN_mod(r1,c,rsa->q,ctx)) goto err;
+ }
+ else
+ {
+ if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
+ }
+
+ /* compute r1^dmq1 mod q */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
{
dmq1 = &local_dmq1;
- BN_with_flags(dmq1, rsa->dmq1, BN_FLG_EXP_CONSTTIME);
+ BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
}
else
dmq1 = rsa->dmq1;
if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
rsa->_method_mod_q)) goto err;
- if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
- if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+ /* compute I mod p */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ c = &local_c;
+ BN_with_flags(c, I, BN_FLG_CONSTTIME);
+ if (!BN_mod(r1,c,rsa->p,ctx)) goto err;
+ }
+ else
+ {
+ if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
+ }
+
+ /* compute r1^dmp1 mod p */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
{
dmp1 = &local_dmp1;
- BN_with_flags(dmp1, rsa->dmp1, BN_FLG_EXP_CONSTTIME);
+ BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
}
else
dmp1 = rsa->dmp1;
@@ -766,7 +813,17 @@ static int RSA_eay_mod_exp(BIGNUM *r0, c
if (!BN_add(r0,r0,rsa->p)) goto err;
if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
- if (!BN_mod(r0,r1,rsa->p,ctx)) goto err;
+
+ /* Turn BN_FLG_CONSTTIME flag on before division operation */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+ {
+ pr1 = &local_r1;
+ BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
+ }
+ else
+ pr1 = r1;
+ if (!BN_mod(r0,pr1,rsa->p,ctx)) goto err;
+
/* If p < q it is occasionally possible for the correction of
* adding 'p' if r0 is negative above to leave the result still
* negative. This can break the private key operations: the following
@@ -799,10 +856,10 @@ static int RSA_eay_mod_exp(BIGNUM *r0, c
BIGNUM local_d;
BIGNUM *d = NULL;
- if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
{
d = &local_d;
- BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+ BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
}
else
d = rsa->d;
diff -up openssl-0.9.8b/crypto/rsa/rsa_test.c.no-branch openssl-0.9.8b/crypto/rsa/rsa_test.c
--- openssl-0.9.8b/crypto/rsa/rsa_test.c.no-branch 2005-05-16 03:43:31.000000000 +0200
+++ openssl-0.9.8b/crypto/rsa/rsa_test.c 2007-08-03 13:58:58.000000000 +0200
@@ -242,7 +242,7 @@ int main(int argc, char *argv[])
clen = key3(key, ctext_ex);
break;
}
- if (v/3 > 1) key->flags |= RSA_FLAG_NO_EXP_CONSTTIME;
+ if (v/3 >= 1) key->flags |= RSA_FLAG_NO_CONSTTIME;
num = RSA_public_encrypt(plen, ptext_ex, ctext, key,
RSA_PKCS1_PADDING);
diff -up openssl-0.9.8b/crypto/bn/bn.h.no-branch openssl-0.9.8b/crypto/bn/bn.h
--- openssl-0.9.8b/crypto/bn/bn.h.no-branch 2007-08-03 13:58:54.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn.h 2007-08-03 13:58:58.000000000 +0200
@@ -245,8 +245,15 @@ extern "C" {
#define BN_FLG_MALLOCED 0x01
#define BN_FLG_STATIC_DATA 0x02
-#define BN_FLG_EXP_CONSTTIME 0x04 /* avoid leaking exponent information through timings
- * (BN_mod_exp_mont() will call BN_mod_exp_mont_consttime) */
+#define BN_FLG_CONSTTIME 0x04 /* avoid leaking exponent information through timing,
+ * BN_mod_exp_mont() will call BN_mod_exp_mont_consttime,
+ * BN_div() will call BN_div_no_branch,
+ * BN_mod_inverse() will call BN_mod_inverse_no_branch.
+ */
+#define BN_FLG_EXP_CONSTTIME BN_FLG_CONSTTIME /* deprecated name for the flag */
+ /* avoid leaking exponent information through timings
+ * (BN_mod_exp_mont() will call BN_mod_exp_mont_consttime) */
+
#ifndef OPENSSL_NO_DEPRECATED
#define BN_FLG_FREE 0x8000 /* used for debuging */
#endif
@@ -534,7 +541,7 @@ BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_M
#define BN_BLINDING_NO_UPDATE 0x00000001
#define BN_BLINDING_NO_RECREATE 0x00000002
-BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod);
+BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, /* const */ BIGNUM *mod);
void BN_BLINDING_free(BN_BLINDING *b);
int BN_BLINDING_update(BN_BLINDING *b,BN_CTX *ctx);
int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
@@ -546,7 +553,7 @@ void BN_BLINDING_set_thread_id(BN_BLINDI
unsigned long BN_BLINDING_get_flags(const BN_BLINDING *);
void BN_BLINDING_set_flags(BN_BLINDING *, unsigned long);
BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
- const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
+ const BIGNUM *e, /* const */ BIGNUM *m, BN_CTX *ctx,
int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
BN_MONT_CTX *m_ctx);
diff -up openssl-0.9.8b/crypto/bn/bn_mont.c.no-branch openssl-0.9.8b/crypto/bn/bn_mont.c
--- openssl-0.9.8b/crypto/bn/bn_mont.c.no-branch 2007-08-03 13:58:54.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn_mont.c 2007-08-03 13:58:58.000000000 +0200
@@ -159,6 +159,7 @@ int BN_from_montgomery(BIGNUM *ret, cons
BIGNUM *n,*r;
BN_ULONG *ap,*np,*rp,n0,v,*nrp;
int al,nl,max,i,x,ri;
+ size_t m1,m2;
BN_CTX_start(ctx);
if ((r = BN_CTX_get(ctx)) == NULL) goto err;
@@ -176,7 +177,6 @@ int BN_from_montgomery(BIGNUM *ret, cons
max=(nl+al+1); /* allow for overflow (no?) XXX */
if (bn_wexpand(r,max) == NULL) goto err;
- if (bn_wexpand(ret,max) == NULL) goto err;
r->neg=a->neg^n->neg;
np=n->d;
@@ -228,37 +228,56 @@ int BN_from_montgomery(BIGNUM *ret, cons
}
bn_correct_top(r);
- /* mont->ri will be a multiple of the word size */
-#if 0
- BN_rshift(ret,r,mont->ri);
-#else
+ /* mont->ri will be a multiple of the word size and below code
+ * is kind of BN_rshift(ret,r,mont->ri) equivalent */
+ if (r->top <= ri)
+ {
+ ret->top=0;
+ retn=1;
+ goto err;
+ }
+ al=r->top-ri;
+ if (bn_wexpand(ret,ri) == NULL) goto err;
+ x=0-(((al-ri)>>(sizeof(al)*8-1))&1);
+ ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */
ret->neg = r->neg;
- x=ri;
+
rp=ret->d;
- ap= &(r->d[x]);
- if (r->top < x)
- al=0;
- else
- al=r->top-x;
- ret->top=al;
- al-=4;
- for (i=0; i<al; i+=4)
+ ap=&(r->d[ri]);
+
+ v=bn_sub_words(rp,ap,np,ri);
+ /* this -----------------------^^ works even in al<ri case
+ * thanks to zealous zeroing of top of the vector in the
+ * beginning. */
+
+ /* if (al==ri && !v) || al>ri) nrp=rp; else nrp=ap; */
+ /* in other words if subtraction result is real, then
+ * trick unconditional memcpy below to perform in-place
+ * "refresh" instead of actual copy. */
+ m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al<ri */
+ m2=0-(size_t)(((ri-al)>>(sizeof(al)*8-1))&1); /* al>ri */
+ m1|=m2; /* (al!=ri) */
+ m1|=(0-(size_t)v); /* (al!=ri || v) */
+ m1&=~m2; /* (al!=ri || v) && !al>ri */
+ nrp=(BN_ULONG *)(((size_t)rp&~m1)|((size_t)ap&m1));
+
+ /* 'i<ri' is chosen to eliminate dependency on input data, even
+ * though it results in redundant copy in al<ri case. */
+ for (i=0,ri-=4; i<ri; i+=4)
{
BN_ULONG t1,t2,t3,t4;
- t1=ap[i+0];
- t2=ap[i+1];
- t3=ap[i+2];
- t4=ap[i+3];
- rp[i+0]=t1;
- rp[i+1]=t2;
+ t1=nrp[i+0];
+ t2=nrp[i+1];
+ t3=nrp[i+2]; ap[i+0]=0;
+ t4=nrp[i+3]; ap[i+1]=0;
+ rp[i+0]=t1; ap[i+2]=0;
+ rp[i+1]=t2; ap[i+3]=0;
rp[i+2]=t3;
rp[i+3]=t4;
}
- al+=4;
- for (; i<al; i++)
- rp[i]=ap[i];
-#endif
+ for (ri+=4; i<ri; i++)
+ rp[i]=nrp[i], ap[i]=0;
#else /* !MONT_WORD */
BIGNUM *t1,*t2;
@@ -276,12 +295,12 @@ int BN_from_montgomery(BIGNUM *ret, cons
if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
if (!BN_add(t2,a,t1)) goto err;
if (!BN_rshift(ret,t2,mont->ri)) goto err;
-#endif /* MONT_WORD */
if (BN_ucmp(ret, &(mont->N)) >= 0)
{
if (!BN_usub(ret,ret,&(mont->N))) goto err;
}
+#endif /* MONT_WORD */
retn=1;
bn_check_top(ret);
err:
diff -up openssl-0.9.8b/crypto/bn/bn_lib.c.no-branch openssl-0.9.8b/crypto/bn/bn_lib.c
--- openssl-0.9.8b/crypto/bn/bn_lib.c.no-branch 2005-05-03 22:27:00.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn_lib.c 2007-08-03 13:58:58.000000000 +0200
@@ -763,7 +763,7 @@ int BN_is_bit_set(const BIGNUM *a, int n
i=n/BN_BITS2;
j=n%BN_BITS2;
if (a->top <= i) return 0;
- return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
+ return(((a->d[i])>>j)&((BN_ULONG)1));
}
int BN_mask_bits(BIGNUM *a, int n)
diff -up openssl-0.9.8b/crypto/bn/bn_blind.c.no-branch openssl-0.9.8b/crypto/bn/bn_blind.c
--- openssl-0.9.8b/crypto/bn/bn_blind.c.no-branch 2005-05-26 06:30:48.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn_blind.c 2007-08-03 13:58:58.000000000 +0200
@@ -131,7 +131,7 @@ struct bn_blinding_st
BN_MONT_CTX *m_ctx);
};
-BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
+BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, /* const */ BIGNUM *mod)
{
BN_BLINDING *ret=NULL;
@@ -151,7 +151,12 @@ BN_BLINDING *BN_BLINDING_new(const BIGNU
{
if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;
}
- ret->mod = mod;
+
+ /* save a copy of mod in the BN_BLINDING structure */
+ if ((ret->mod = BN_dup(mod)) == NULL) goto err;
+ if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
+ BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
+
ret->counter = BN_BLINDING_COUNTER;
return(ret);
err:
@@ -167,6 +172,7 @@ void BN_BLINDING_free(BN_BLINDING *r)
if (r->A != NULL) BN_free(r->A );
if (r->Ai != NULL) BN_free(r->Ai);
if (r->e != NULL) BN_free(r->e );
+ if (r->mod != NULL) BN_free(r->mod);
OPENSSL_free(r);
}
@@ -278,7 +284,7 @@ void BN_BLINDING_set_flags(BN_BLINDING *
}
BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
- const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
+ const BIGNUM *e, /* const */ BIGNUM *m, BN_CTX *ctx,
int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
BN_MONT_CTX *m_ctx)
diff -up openssl-0.9.8b/crypto/bn/bn_div.c.no-branch openssl-0.9.8b/crypto/bn/bn_div.c
--- openssl-0.9.8b/crypto/bn/bn_div.c.no-branch 2005-08-29 01:20:43.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn_div.c 2007-08-03 13:58:58.000000000 +0200
@@ -169,13 +169,15 @@ int BN_div(BIGNUM *dv, BIGNUM *rem, cons
#endif /* OPENSSL_NO_ASM */
-/* BN_div computes dv := num / divisor, rounding towards zero, and sets up
- * rm such that dv*divisor + rm = num holds.
+/* BN_div[_no_branch] computes dv := num / divisor, rounding towards
+ * zero, and sets up rm such that dv*divisor + rm = num holds.
* Thus:
* dv->neg == num->neg ^ divisor->neg (unless the result is zero)
* rm->neg == num->neg (unless the remainder is zero)
* If 'dv' or 'rm' is NULL, the respective value is not returned.
*/
+static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
+ const BIGNUM *divisor, BN_CTX *ctx);
int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
BN_CTX *ctx)
{
@@ -185,6 +187,11 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const
BN_ULONG d0,d1;
int num_n,div_n;
+ if (BN_get_flags(num, BN_FLG_CONSTTIME) != 0)
+ {
+ return BN_div_no_branch(dv, rm, num, divisor, ctx);
+ }
+
bn_check_top(dv);
bn_check_top(rm);
bn_check_top(num);
@@ -397,4 +404,229 @@ err:
return(0);
}
+
+/* BN_div_no_branch is a special version of BN_div. It does not contain
+ * branches that may leak sensitive information.
+ */
+static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
+ const BIGNUM *divisor, BN_CTX *ctx)
+ {
+ int norm_shift,i,loop;
+ BIGNUM *tmp,wnum,*snum,*sdiv,*res;
+ BN_ULONG *resp,*wnump;
+ BN_ULONG d0,d1;
+ int num_n,div_n;
+
+ bn_check_top(dv);
+ bn_check_top(rm);
+ bn_check_top(num);
+ bn_check_top(divisor);
+
+ if (BN_is_zero(divisor))
+ {
+ BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
+ return(0);
+ }
+
+ BN_CTX_start(ctx);
+ tmp=BN_CTX_get(ctx);
+ snum=BN_CTX_get(ctx);
+ sdiv=BN_CTX_get(ctx);
+ if (dv == NULL)
+ res=BN_CTX_get(ctx);
+ else res=dv;
+ if (sdiv == NULL || res == NULL) goto err;
+
+ /* First we normalise the numbers */
+ norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
+ if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
+ sdiv->neg=0;
+ norm_shift+=BN_BITS2;
+ if (!(BN_lshift(snum,num,norm_shift))) goto err;
+ snum->neg=0;
+
+ /* Since we don't know whether snum is larger than sdiv,
+ * we pad snum with enough zeroes without changing its
+ * value.
+ */
+ if (snum->top <= sdiv->top+1)
+ {
+ if (bn_wexpand(snum, sdiv->top + 2) == NULL) goto err;
+ for (i = snum->top; i < sdiv->top + 2; i++) snum->d[i] = 0;
+ snum->top = sdiv->top + 2;
+ }
+ else
+ {
+ if (bn_wexpand(snum, snum->top + 1) == NULL) goto err;
+ snum->d[snum->top] = 0;
+ snum->top ++;
+ }
+
+ div_n=sdiv->top;
+ num_n=snum->top;
+ loop=num_n-div_n;
+ /* Lets setup a 'window' into snum
+ * This is the part that corresponds to the current
+ * 'area' being divided */
+ wnum.neg = 0;
+ wnum.d = &(snum->d[loop]);
+ wnum.top = div_n;
+ /* only needed when BN_ucmp messes up the values between top and max */
+ wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */
+
+ /* Get the top 2 words of sdiv */
+ /* div_n=sdiv->top; */
+ d0=sdiv->d[div_n-1];
+ d1=(div_n == 1)?0:sdiv->d[div_n-2];
+
+ /* pointer to the 'top' of snum */
+ wnump= &(snum->d[num_n-1]);
+
+ /* Setup to 'res' */
+ res->neg= (num->neg^divisor->neg);
+ if (!bn_wexpand(res,(loop+1))) goto err;
+ res->top=loop-1;
+ resp= &(res->d[loop-1]);
+
+ /* space for temp */
+ if (!bn_wexpand(tmp,(div_n+1))) goto err;
+
+ /* if res->top == 0 then clear the neg value otherwise decrease
+ * the resp pointer */
+ if (res->top == 0)
+ res->neg = 0;
+ else
+ resp--;
+
+ for (i=0; i<loop-1; i++, wnump--, resp--)
+ {
+ BN_ULONG q,l0;
+ /* the first part of the loop uses the top two words of
+ * snum and sdiv to calculate a BN_ULONG q such that
+ * | wnum - sdiv * q | < sdiv */
+#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)
+ BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
+ q=bn_div_3_words(wnump,d1,d0);
+#else
+ BN_ULONG n0,n1,rem=0;
+
+ n0=wnump[0];
+ n1=wnump[-1];
+ if (n0 == d0)
+ q=BN_MASK2;
+ else /* n0 < d0 */
+ {
+#ifdef BN_LLONG
+ BN_ULLONG t2;
+
+#if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
+ q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
+#else
+ q=bn_div_words(n0,n1,d0);
+#ifdef BN_DEBUG_LEVITTE
+ fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
+X) -> 0x%08X\n",
+ n0, n1, d0, q);
+#endif
+#endif
+
+#ifndef REMAINDER_IS_ALREADY_CALCULATED
+ /*
+ * rem doesn't have to be BN_ULLONG. The least we
+ * know it's less that d0, isn't it?
+ */
+ rem=(n1-q*d0)&BN_MASK2;
+#endif
+ t2=(BN_ULLONG)d1*q;
+
+ for (;;)
+ {
+ if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2]))
+ break;
+ q--;
+ rem += d0;
+ if (rem < d0) break; /* don't let rem overflow */
+ t2 -= d1;
+ }
+#else /* !BN_LLONG */
+ BN_ULONG t2l,t2h,ql,qh;
+
+ q=bn_div_words(n0,n1,d0);
+#ifdef BN_DEBUG_LEVITTE
+ fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
+X) -> 0x%08X\n",
+ n0, n1, d0, q);
+#endif
+#ifndef REMAINDER_IS_ALREADY_CALCULATED
+ rem=(n1-q*d0)&BN_MASK2;
+#endif
+
+#if defined(BN_UMULT_LOHI)
+ BN_UMULT_LOHI(t2l,t2h,d1,q);
+#elif defined(BN_UMULT_HIGH)
+ t2l = d1 * q;
+ t2h = BN_UMULT_HIGH(d1,q);
+#else
+ t2l=LBITS(d1); t2h=HBITS(d1);
+ ql =LBITS(q); qh =HBITS(q);
+ mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
+#endif
+
+ for (;;)
+ {
+ if ((t2h < rem) ||
+ ((t2h == rem) && (t2l <= wnump[-2])))
+ break;
+ q--;
+ rem += d0;
+ if (rem < d0) break; /* don't let rem overflow */
+ if (t2l < d1) t2h--; t2l -= d1;
+ }
+#endif /* !BN_LLONG */
+ }
+#endif /* !BN_DIV3W */
+
+ l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
+ tmp->d[div_n]=l0;
+ wnum.d--;
+ /* ingore top values of the bignums just sub the two
+ * BN_ULONG arrays with bn_sub_words */
+ if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1))
+ {
+ /* Note: As we have considered only the leading
+ * two BN_ULONGs in the calculation of q, sdiv * q
+ * might be greater than wnum (but then (q-1) * sdiv
+ * is less or equal than wnum)
+ */
+ q--;
+ if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n))
+ /* we can't have an overflow here (assuming
+ * that q != 0, but if q == 0 then tmp is
+ * zero anyway) */
+ (*wnump)++;
+ }
+ /* store part of the result */
+ *resp = q;
+ }
+ bn_correct_top(snum);
+ if (rm != NULL)
+ {
+ /* Keep a copy of the neg flag in num because if rm==num
+ * BN_rshift() will overwrite it.
+ */
+ int neg = num->neg;
+ BN_rshift(rm,snum,norm_shift);
+ if (!BN_is_zero(rm))
+ rm->neg = neg;
+ bn_check_top(rm);
+ }
+ bn_correct_top(res);
+ BN_CTX_end(ctx);
+ return(1);
+err:
+ bn_check_top(rm);
+ BN_CTX_end(ctx);
+ return(0);
+ }
+
#endif
diff -up openssl-0.9.8b/crypto/bn/bn_gcd.c.no-branch openssl-0.9.8b/crypto/bn/bn_gcd.c
--- openssl-0.9.8b/crypto/bn/bn_gcd.c.no-branch 2005-08-29 01:20:43.000000000 +0200
+++ openssl-0.9.8b/crypto/bn/bn_gcd.c 2007-08-03 13:58:58.000000000 +0200
@@ -203,6 +203,8 @@ err:
/* solves ax == 1 (mod n) */
+static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,
+ const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx);
BIGNUM *BN_mod_inverse(BIGNUM *in,
const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
{
@@ -210,6 +212,11 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
BIGNUM *ret=NULL;
int sign;
+ if (BN_get_flags(n, BN_FLG_CONSTTIME) != 0)
+ {
+ return BN_mod_inverse_no_branch(in, a, n, ctx);
+ }
+
bn_check_top(a);
bn_check_top(n);
@@ -491,3 +498,157 @@ err:
bn_check_top(ret);
return(ret);
}
+
+
+/* BN_mod_inverse_no_branch is a special version of BN_mod_inverse.
+ * It does not contain branches that may leak sensitive information.
+ */
+static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,
+ const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
+ {
+ BIGNUM *A,*B,*X,*Y,*M,*D,*T,*R=NULL;
+ BIGNUM local_A, local_B;
+ BIGNUM *pA, *pB;
+ BIGNUM *ret=NULL;
+ int sign;
+
+ bn_check_top(a);
+ bn_check_top(n);
+
+ BN_CTX_start(ctx);
+ A = BN_CTX_get(ctx);
+ B = BN_CTX_get(ctx);
+ X = BN_CTX_get(ctx);
+ D = BN_CTX_get(ctx);
+ M = BN_CTX_get(ctx);
+ Y = BN_CTX_get(ctx);
+ T = BN_CTX_get(ctx);
+ if (T == NULL) goto err;
+
+ if (in == NULL)
+ R=BN_new();
+ else
+ R=in;
+ if (R == NULL) goto err;
+
+ BN_one(X);
+ BN_zero(Y);
+ if (BN_copy(B,a) == NULL) goto err;
+ if (BN_copy(A,n) == NULL) goto err;
+ A->neg = 0;
+
+ if (B->neg || (BN_ucmp(B, A) >= 0))
+ {
+ /* Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked,
+ * BN_div_no_branch will be called eventually.
+ */
+ pB = &local_B;
+ BN_with_flags(pB, B, BN_FLG_CONSTTIME);
+ if (!BN_nnmod(B, pB, A, ctx)) goto err;
+ }
+ sign = -1;
+ /* From B = a mod |n|, A = |n| it follows that
+ *
+ * 0 <= B < A,
+ * -sign*X*a == B (mod |n|),
+ * sign*Y*a == A (mod |n|).
+ */
+
+ while (!BN_is_zero(B))
+ {
+ BIGNUM *tmp;
+
+ /*
+ * 0 < B < A,
+ * (*) -sign*X*a == B (mod |n|),
+ * sign*Y*a == A (mod |n|)
+ */
+
+ /* Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked,
+ * BN_div_no_branch will be called eventually.
+ */
+ pA = &local_A;
+ BN_with_flags(pA, A, BN_FLG_CONSTTIME);
+
+ /* (D, M) := (A/B, A%B) ... */
+ if (!BN_div(D,M,pA,B,ctx)) goto err;
+
+ /* Now
+ * A = D*B + M;
+ * thus we have
+ * (**) sign*Y*a == D*B + M (mod |n|).
+ */
+
+ tmp=A; /* keep the BIGNUM object, the value does not matter */
+
+ /* (A, B) := (B, A mod B) ... */
+ A=B;
+ B=M;
+ /* ... so we have 0 <= B < A again */
+
+ /* Since the former M is now B and the former B is now A,
+ * (**) translates into
+ * sign*Y*a == D*A + B (mod |n|),
+ * i.e.
+ * sign*Y*a - D*A == B (mod |n|).
+ * Similarly, (*) translates into
+ * -sign*X*a == A (mod |n|).
+ *
+ * Thus,
+ * sign*Y*a + D*sign*X*a == B (mod |n|),
+ * i.e.
+ * sign*(Y + D*X)*a == B (mod |n|).
+ *
+ * So if we set (X, Y, sign) := (Y + D*X, X, -sign), we arrive back at
+ * -sign*X*a == B (mod |n|),
+ * sign*Y*a == A (mod |n|).
+ * Note that X and Y stay non-negative all the time.
+ */
+
+ if (!BN_mul(tmp,D,X,ctx)) goto err;
+ if (!BN_add(tmp,tmp,Y)) goto err;
+
+ M=Y; /* keep the BIGNUM object, the value does not matter */
+ Y=X;
+ X=tmp;
+ sign = -sign;
+ }
+
+ /*
+ * The while loop (Euclid's algorithm) ends when
+ * A == gcd(a,n);
+ * we have
+ * sign*Y*a == A (mod |n|),
+ * where Y is non-negative.
+ */
+
+ if (sign < 0)
+ {
+ if (!BN_sub(Y,n,Y)) goto err;
+ }
+ /* Now Y*a == A (mod |n|). */
+
+ if (BN_is_one(A))
+ {
+ /* Y*a == 1 (mod |n|) */
+ if (!Y->neg && BN_ucmp(Y,n) < 0)
+ {
+ if (!BN_copy(R,Y)) goto err;
+ }
+ else
+ {
+ if (!BN_nnmod(R,Y,n,ctx)) goto err;
+ }
+ }
+ else
+ {
+ BNerr(BN_F_BN_MOD_INVERSE,BN_R_NO_INVERSE);
+ goto err;
+ }
+ ret=R;
+err:
+ if ((ret == NULL) && (in == NULL)) BN_free(R);
+ BN_CTX_end(ctx);
+ bn_check_top(ret);
+ return(ret);
+ }
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