[openssl-commits] [openssl] master update
Rich Salz
rsalz at openssl.org
Tue Sep 6 14:42:47 UTC 2016
The branch master has been updated
via 01c09f9fde5793e0b3712d602b02e2aed4908e8d (commit)
from 77a42b5f177e308233ab108806c48b9590a780e2 (commit)
- Log -----------------------------------------------------------------
commit 01c09f9fde5793e0b3712d602b02e2aed4908e8d
Author: Rich Salz <rsalz at openssl.org>
Date: Mon Sep 5 18:08:43 2016 -0400
Misc BN fixes
Never output -0; make "negative zero" an impossibility.
Do better checking on BN_rand top/bottom requirements and #bits.
Update doc.
Ignoring trailing garbage in BN_asc2bn.
Port this commit from boringSSL: https://boringssl.googlesource.com/boringssl/+/899b9b19a4cd3fe526aaf5047ab9234cdca19f7d%5E!/
Ensure |BN_div| never gives negative zero in the no_branch code.
Have |bn_correct_top| fix |bn->neg| if the input is zero so that we
don't have negative zeros lying around.
Thanks to Brian Smith for noticing.
Reviewed-by: Richard Levitte <levitte at openssl.org>
-----------------------------------------------------------------------
Summary of changes:
crypto/bn/bn_lib.c | 2 ++
crypto/bn/bn_print.c | 23 +++++++++++++----------
crypto/bn/bn_rand.c | 13 ++++++++-----
doc/crypto/BN_bn2bin.pod | 1 +
doc/crypto/BN_rand.pod | 4 +++-
5 files changed, 27 insertions(+), 16 deletions(-)
diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index 0be42f8..17d34c3 100644
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -1031,5 +1031,7 @@ void bn_correct_top(BIGNUM *a)
}
a->top = tmp_top;
}
+ if (a->top == 0)
+ a->neg = 0;
bn_pollute(a);
}
diff --git a/crypto/bn/bn_print.c b/crypto/bn/bn_print.c
index 39fb034..a16bde8 100644
--- a/crypto/bn/bn_print.c
+++ b/crypto/bn/bn_print.c
@@ -23,12 +23,9 @@ char *BN_bn2hex(const BIGNUM *a)
char *buf;
char *p;
- if (a->neg && BN_is_zero(a)) {
- /* "-0" == 3 bytes including NULL terminator */
- buf = OPENSSL_malloc(3);
- } else {
- buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
- }
+ if (BN_is_zero(a))
+ return OPENSSL_strdup("0");
+ buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
if (buf == NULL) {
BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
goto err;
@@ -186,10 +183,12 @@ int BN_hex2bn(BIGNUM **bn, const char *a)
}
ret->top = h;
bn_correct_top(ret);
- ret->neg = neg;
*bn = ret;
bn_check_top(ret);
+ /* Don't set the negative flag if it's zero. */
+ if (ret->top != 0)
+ ret->neg = neg;
return (num);
err:
if (*bn == NULL)
@@ -241,7 +240,7 @@ int BN_dec2bn(BIGNUM **bn, const char *a)
if (j == BN_DEC_NUM)
j = 0;
l = 0;
- while (*a) {
+ while (--i >= 0) {
l *= 10;
l += *a - '0';
a++;
@@ -253,11 +252,13 @@ int BN_dec2bn(BIGNUM **bn, const char *a)
j = 0;
}
}
- ret->neg = neg;
bn_correct_top(ret);
*bn = ret;
bn_check_top(ret);
+ /* Don't set the negative flag if it's zero. */
+ if (ret->top != 0)
+ ret->neg = neg;
return (num);
err:
if (*bn == NULL)
@@ -268,6 +269,7 @@ int BN_dec2bn(BIGNUM **bn, const char *a)
int BN_asc2bn(BIGNUM **bn, const char *a)
{
const char *p = a;
+
if (*p == '-')
p++;
@@ -278,7 +280,8 @@ int BN_asc2bn(BIGNUM **bn, const char *a)
if (!BN_dec2bn(bn, p))
return 0;
}
- if (*a == '-')
+ /* Don't set the negative flag if it's zero. */
+ if (*a == '-' && (*bn)->top != 0)
(*bn)->neg = 1;
return 1;
}
diff --git a/crypto/bn/bn_rand.c b/crypto/bn/bn_rand.c
index 5ad8050..c577fd1 100644
--- a/crypto/bn/bn_rand.c
+++ b/crypto/bn/bn_rand.c
@@ -20,15 +20,14 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
int ret = 0, bit, bytes, mask;
time_t tim;
- if (bits < 0 || (bits == 1 && top > 0)) {
- BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
- return 0;
- }
-
if (bits == 0) {
+ if (top != BN_RAND_TOP_ANY || bottom != BN_RAND_BOTTOM_ANY)
+ goto toosmall;
BN_zero(rnd);
return 1;
}
+ if (bits < 0 || (bits == 1 && top > 0))
+ goto toosmall;
bytes = (bits + 7) / 8;
bit = (bits - 1) % 8;
@@ -88,6 +87,10 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
OPENSSL_clear_free(buf, bytes);
bn_check_top(rnd);
return (ret);
+
+toosmall:
+ BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
+ return 0;
}
int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
diff --git a/doc/crypto/BN_bn2bin.pod b/doc/crypto/BN_bn2bin.pod
index 14b152e..b272010 100644
--- a/doc/crypto/BN_bn2bin.pod
+++ b/doc/crypto/BN_bn2bin.pod
@@ -57,6 +57,7 @@ including the leading character '-' which means negative, to form a valid
hexadecimal number representation and converts them to a B<BIGNUM> and
stores it in **B<bn>. If *B<bn> is NULL, a new B<BIGNUM> is created. If
B<bn> is NULL, it only computes the length of valid representation.
+A "negative zero" is converted to zero.
BN_dec2bn() is the same using the decimal system.
BN_print() and BN_print_fp() write the hexadecimal encoding of B<a>,
diff --git a/doc/crypto/BN_rand.pod b/doc/crypto/BN_rand.pod
index ba505e1..ae15ada 100644
--- a/doc/crypto/BN_rand.pod
+++ b/doc/crypto/BN_rand.pod
@@ -20,7 +20,9 @@ BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-r
BN_rand() generates a cryptographically strong pseudo-random number of
B<bits> in length and stores it in B<rnd>.
-The value of B<bits> must be zero or greater.
+If B<bits> is less than zero, or too small to
+accomodate the requirements specified by the B<top> and B<bottom>
+parameters, an error is returned.
The B<top> parameters specifies
requirements on the most significant bit of the generated number.
If it is B<BN_RAND_TOP_ANY>, there is no constraint.
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