#endif
#include <assert.h>
+#include <limits.h>
#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"
else return(0);
}
-BIGNUM *BN_value_one(void)
+const BIGNUM *BN_value_one(void)
{
static BN_ULONG data_one=1L;
static BIGNUM const_one={&data_one,1,1,0};
/* This is used both by bn_expand2() and bn_dup_expand() */
/* The caller MUST check that words > b->dmax before calling this */
-static BN_ULONG *internal_bn_expand(const BIGNUM *b, int words)
+static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
{
BN_ULONG *A,*a = NULL;
const BN_ULONG *B;
int i;
+ if (words > (INT_MAX/(4*BN_BITS2)))
+ {
+ BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
+ return NULL;
+ }
+
bn_check_top(b);
if (BN_get_flags(b,BN_FLG_STATIC_DATA))
{
- BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
+ BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
return(NULL);
}
a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
if (A == NULL)
{
- BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
+ BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
return(NULL);
}
#if 1
/* Check if the previous number needs to be copied */
if (B != NULL)
{
-#if 0
- /* This lot is an unrolled loop to copy b->top
- * BN_ULONGs from B to A
- */
-/*
- * I have nothing against unrolling but it's usually done for
- * several reasons, namely:
- * - minimize percentage of decision making code, i.e. branches;
- * - avoid cache trashing;
- * - make it possible to schedule loads earlier;
- * Now let's examine the code below. The cornerstone of C is
- * "programmer is always right" and that's what we love it for:-)
- * For this very reason C compilers have to be paranoid when it
- * comes to data aliasing and assume the worst. Yeah, but what
- * does it mean in real life? This means that loop body below will
- * be compiled to sequence of loads immediately followed by stores
- * as compiler assumes the worst, something in A==B+1 style. As a
- * result CPU pipeline is going to starve for incoming data. Secondly
- * if A and B happen to share same cache line such code is going to
- * cause severe cache trashing. Both factors have severe impact on
- * performance of modern CPUs and this is the reason why this
- * particular piece of code is #ifdefed away and replaced by more
- * "friendly" version found in #else section below. This comment
- * also applies to BN_copy function.
- *
- * <appro@fy.chalmers.se>
- */
- for (i=b->top&(~7); i>0; i-=8)
- {
- A[0]=B[0]; A[1]=B[1]; A[2]=B[2]; A[3]=B[3];
- A[4]=B[4]; A[5]=B[5]; A[6]=B[6]; A[7]=B[7];
- A+=8;
- B+=8;
- }
- switch (b->top&7)
- {
- case 7:
- A[6]=B[6];
- case 6:
- A[5]=B[5];
- case 5:
- A[4]=B[4];
- case 4:
- A[3]=B[3];
- case 3:
- A[2]=B[2];
- case 2:
- A[1]=B[1];
- case 1:
- A[0]=B[0];
- case 0:
- /* I need the 'case 0' entry for utrix cc.
- * If the optimizer is turned on, it does the
- * switch table by doing
- * a=top&7
- * a--;
- * goto jump_table[a];
- * If top is 0, this makes us jump to 0xffffffc
- * which is rather bad :-(.
- * eric 23-Apr-1998
- */
- ;
- }
-#else
for (i=b->top>>2; i>0; i--,A+=4,B+=4)
{
/*
case 3: A[2]=B[2];
case 2: A[1]=B[1];
case 1: A[0]=B[0];
- case 0: ; /* ultrix cc workaround, see above */
+ case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
+ * the switch table by doing a=top&3; a--; goto jump_table[a];
+ * which fails for top== 0 */
+ ;
}
-#endif
}
- /* Now need to zero any data between b->top and b->max */
-
- A= &(a[b->top]);
- for (i=(words - b->top)>>3; i>0; i--,A+=8)
- {
- A[0]=0; A[1]=0; A[2]=0; A[3]=0;
- A[4]=0; A[5]=0; A[6]=0; A[7]=0;
- }
- for (i=(words - b->top)&7; i>0; i--,A++)
- A[0]=0;
#else
memset(A,0,sizeof(BN_ULONG)*(words+1));
memcpy(A,b->d,sizeof(b->d[0])*b->top);
{
BIGNUM *r = NULL;
+ /* This function does not work if
+ * words <= b->dmax && top < words
+ * because BN_dup() does not preserve 'dmax'!
+ * (But bn_dup_expand() is not used anywhere yet.)
+ */
+
if (words > b->dmax)
{
- BN_ULONG *a = internal_bn_expand(b, words);
+ BN_ULONG *a = bn_expand_internal(b, words);
if (a)
{
r = BN_new();
- r->top = b->top;
- r->dmax = words;
- r->neg = b->neg;
- r->d = a;
+ if (r)
+ {
+ r->top = b->top;
+ r->dmax = words;
+ r->neg = b->neg;
+ r->d = a;
+ }
+ else
+ {
+ /* r == NULL, BN_new failure */
+ OPENSSL_free(a);
+ }
}
- /* Otherwise, there was an error in allocation in
- internal_bn_expand(), and NULL should be returned */
+ /* If a == NULL, there was an error in allocation in
+ bn_expand_internal(), and NULL should be returned */
}
else
{
}
/* This is an internal function that should not be used in applications.
- * It ensures that 'b' has enough room for a 'words' word number number.
+ * It ensures that 'b' has enough room for a 'words' word number
+ * and initialises the unused part of b->d with leading zeros.
* It is mostly used by the various BIGNUM routines. If there is an error,
* NULL is returned. If not, 'b' is returned. */
BIGNUM *bn_expand2(BIGNUM *b, int words)
{
+ BN_ULONG *A;
+ int i;
+
if (words > b->dmax)
{
- BN_ULONG *a = internal_bn_expand(b, words);
+ BN_ULONG *a = bn_expand_internal(b, words);
if (a)
{
- OPENSSL_free(b->d);
+ if (b->d)
+ OPENSSL_free(b->d);
b->d=a;
b->dmax=words;
}
else
b = NULL;
}
+
+ /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
+ A = &(b->d[b->top]);
+ for (i=(words - b->top)>>3; i>0; i--,A+=8)
+ {
+ A[0]=0; A[1]=0; A[2]=0; A[3]=0;
+ A[4]=0; A[5]=0; A[6]=0; A[7]=0;
+ }
+ for (i=(words - b->top)&7; i>0; i--,A++)
+ A[0]=0;
+
return b;
}
BIGNUM *BN_dup(const BIGNUM *a)
{
- BIGNUM *r;
+ BIGNUM *r, *t;
if (a == NULL) return NULL;
bn_check_top(a);
- r=BN_new();
- if (r == NULL) return(NULL);
- return((BIGNUM *)BN_copy(r,a));
+ t = BN_new();
+ if (t == NULL) return(NULL);
+ r = BN_copy(t, a);
+ /* now r == t || r == NULL */
+ if (r == NULL)
+ BN_free(t);
+ return r;
}
BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
case 3: A[2]=B[2];
case 2: A[1]=B[1];
case 1: A[0]=B[0];
- case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
+ case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
}
#else
memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
return(a);
}
+void BN_swap(BIGNUM *a, BIGNUM *b)
+ {
+ int flags_old_a, flags_old_b;
+ BN_ULONG *tmp_d;
+ int tmp_top, tmp_dmax, tmp_neg;
+
+ flags_old_a = a->flags;
+ flags_old_b = b->flags;
+
+ tmp_d = a->d;
+ tmp_top = a->top;
+ tmp_dmax = a->dmax;
+ tmp_neg = a->neg;
+
+ a->d = b->d;
+ a->top = b->top;
+ a->dmax = b->dmax;
+ a->neg = b->neg;
+
+ b->d = tmp_d;
+ b->top = tmp_top;
+ b->dmax = tmp_dmax;
+ b->neg = tmp_neg;
+
+ a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
+ b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
+ }
+
+
void BN_clear(BIGNUM *a)
{
if (a->d != NULL)
return(1);
}
-/* ignore negative */
BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
{
unsigned int i,m;
i=((n-1)/BN_BYTES)+1;
m=((n-1)%(BN_BYTES));
ret->top=i;
+ ret->neg=0;
while (n-- > 0)
{
l=(l<<8L)| *(s++);
return(1);
}
-int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n)
+int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
{
int i;
BN_ULONG aa,bb;
return(0);
}
+/* Here follows a specialised variants of bn_cmp_words(). It has the
+ property of performing the operation on arrays of different sizes.
+ The sizes of those arrays is expressed through cl, which is the
+ common length ( basicall, min(len(a),len(b)) ), and dl, which is the
+ delta between the two lengths, calculated as len(a)-len(b).
+ All lengths are the number of BN_ULONGs... */
+
+int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
+ int cl, int dl)
+ {
+ int n,i;
+ n = cl-1;
+
+ if (dl < 0)
+ {
+ for (i=dl; i<0; i++)
+ {
+ if (b[n-i] != 0)
+ return -1; /* a < b */
+ }
+ }
+ if (dl > 0)
+ {
+ for (i=dl; i>0; i--)
+ {
+ if (a[n+i] != 0)
+ return 1; /* a > b */
+ }
+ }
+ return bn_cmp_words(a,b,cl);
+ }
projects / openssl.git / blobdiff