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Fix BN_[pseudo_]rand: 'mask' must be used even if top=-1.

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Mention BN_[pseudo_]rand with top=-1 in CHANGES.
This commit is contained in:
Bodo Möller 2001-02-20 08:22:25 +00:00
parent 6c66fcba5f
commit 6d82a20624
2 changed files with 8 additions and 7 deletions
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3
CHANGES
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@ -39,6 +39,9 @@
*) Add new function BN_rand_range(), and fix DSA_sign_setup() to prevent *) Add new function BN_rand_range(), and fix DSA_sign_setup() to prevent
Bleichenbacher's DSA attack. Bleichenbacher's DSA attack.
Extend BN_[pseudo_]rand: As before, top=1 forces the highest two bits
to be set and top=0 forces the highest bit to be set; top=-1 is new
and leaves the highest bit random.
[Ulf Moeller] [Ulf Moeller]
*) In the NCONF_...-based implementations for CONF_... queries *) In the NCONF_...-based implementations for CONF_... queries

12
crypto/bn/bn_rand.c
View file

@ -76,7 +76,7 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
bytes=(bits+7)/8; bytes=(bits+7)/8;
bit=(bits-1)%8; bit=(bits-1)%8;
mask=0xff<<bit; mask=0xff<<(bit+1);
buf=(unsigned char *)OPENSSL_malloc(bytes); buf=(unsigned char *)OPENSSL_malloc(bytes);
if (buf == NULL) if (buf == NULL)
@ -104,7 +104,7 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
{ {
if (top) if (top)
{ {
if (bit == 0) if (bit == 0)
{ {
buf[0]=1; buf[0]=1;
buf[1]|=0x80; buf[1]|=0x80;
@ -112,16 +112,15 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
else else
{ {
buf[0]|=(3<<(bit-1)); buf[0]|=(3<<(bit-1));
buf[0]&= ~(mask<<1);
} }
} }
else else
{ {
buf[0]|=(1<<bit); buf[0]|=(1<<bit);
buf[0]&= ~(mask<<1);
} }
} }
if (bottom) /* set bottom bits to whatever odd is */ buf[0] &= ~mask;
if (bottom) /* set bottom bit if requested */
buf[bytes-1]|=1; buf[bytes-1]|=1;
if (!BN_bin2bn(buf,bytes,rnd)) goto err; if (!BN_bin2bn(buf,bytes,rnd)) goto err;
ret=1; ret=1;
@ -156,7 +155,7 @@ int BN_rand_range(BIGNUM *r, BIGNUM *range)
} }
n = BN_num_bits(range); /* n > 0 */ n = BN_num_bits(range); /* n > 0 */
if (n == 1) if (n == 1)
{ {
if (!BN_zero(r)) return 0; if (!BN_zero(r)) return 0;
@ -194,4 +193,3 @@ int BN_rand_range(BIGNUM *r, BIGNUM *range)
return 1; return 1;
} }