#endif
#include <assert.h>
+#include <limits.h>
#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"
return(ret);
}
-/* 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 *bn_expand_internal(const BIGNUM *b, int words)
+/* 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 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,*a = NULL;
+ BN_ULONG *A,*a;
const BN_ULONG *B;
int i;
- bn_check_top(b);
- if (BN_get_flags(b,BN_FLG_STATIC_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_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
- return(NULL);
- }
-#if 1
- B=b->d;
- /* Check if the previous number needs to be copied */
- if (B != NULL)
+ bn_check_top(b);
+
+ if (words > b->dmax)
{
- for (i=b->top>>2; i>0; i--,A+=4,B+=4)
+ if (words > (INT_MAX/(4*BN_BITS2)))
{
- /*
- * The fact that the loop is unrolled
- * 4-wise is a tribute to Intel. It's
- * the one that doesn't have enough
- * registers to accomodate more data.
- * I'd unroll it 8-wise otherwise:-)
- *
- * <appro@fy.chalmers.se>
- */
- BN_ULONG a0,a1,a2,a3;
- a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
- A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
+ BNerr(BN_F_BN_EXPAND2,BN_R_BIGNUM_TOO_LONG);
+ return NULL;
}
- switch (b->top&3)
+
+ bn_check_top(b);
+ if (BN_get_flags(b,BN_FLG_STATIC_DATA))
{
- case 3: A[2]=B[2];
- case 2: A[1]=B[1];
- case 1: A[0]=B[0];
- 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 */
- ;
+ BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
+ return(NULL);
}
- }
-
- /* 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);
-#endif
-
- return(a);
- }
-
-/* This is an internal function that can be used instead of bn_expand2()
- * when there is a need to copy BIGNUMs instead of only expanding the
- * data part, while still expanding them.
- * Especially useful when needing to expand BIGNUMs that are declared
- * 'const' and should therefore not be changed.
- * The reason to use this instead of a BN_dup() followed by a bn_expand2()
- * is memory allocation overhead. A BN_dup() followed by a bn_expand2()
- * will allocate new memory for the BIGNUM data twice, and free it once,
- * while bn_dup_expand() makes sure allocation is made only once.
- */
-
-BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
- {
- BIGNUM *r = NULL;
-
- if (words > b->dmax)
- {
- BN_ULONG *a = bn_expand_internal(b, words);
-
- if (a)
+ a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
+ if (A == NULL)
{
- r = BN_new();
- if (r)
+ BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
+ return(NULL);
+ }
+#if 1
+ B=b->d;
+ /* 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)
{
- r->top = b->top;
- r->dmax = words;
- r->neg = b->neg;
- r->d = a;
+ /*
+ * The fact that the loop is unrolled
+ * 4-wise is a tribute to Intel. It's
+ * the one that doesn't have enough
+ * registers to accomodate more data.
+ * I'd unroll it 8-wise otherwise:-)
+ *
+ * <appro@fy.chalmers.se>
+ */
+ BN_ULONG a0,a1,a2,a3;
+ a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
+ A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
}
- else
+ switch (b->top&3)
{
- /* r == NULL, BN_new failure */
- OPENSSL_free(a);
+ 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 */
}
+#endif
+ OPENSSL_free(b->d);
}
- /* If a == NULL, there was an error in allocation in
- bn_expand_internal(), and NULL should be returned */
- }
- else
- {
- r = BN_dup(b);
- }
-
- return r;
- }
-/* 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 is mostly used by the various BIGNUM routines. If there is an error,
- * NULL is returned. If not, 'b' is returned. */
+ b->d=a;
+ b->dmax=words;
-BIGNUM *bn_expand2(BIGNUM *b, int words)
- {
- if (words > b->dmax)
- {
- BN_ULONG *a = bn_expand_internal(b, words);
+ /* Now need to zero any data between b->top and b->max */
- if (a)
+ A= &(b->d[b->top]);
+ for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
{
- if (b->d)
- OPENSSL_free(b->d);
- b->d=a;
- b->dmax=words;
+ A[0]=0; A[1]=0; A[2]=0; A[3]=0;
+ A[4]=0; A[5]=0; A[6]=0; A[7]=0;
}
- else
- b = NULL;
+ for (i=(b->dmax - 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);
+ b->d=a;
+ b->max=words;
+#endif
+
+/* memset(&(p[b->max]),0,((words+1)-b->max)*sizeof(BN_ULONG)); */
+/* { int i; for (i=b->max; i<words+1; i++) p[i]=i;} */
+
}
- return b;
+ return(b);
}
BIGNUM *BN_dup(const BIGNUM *a)
{
- BIGNUM *r, *t;
+ BIGNUM *r;
if (a == NULL) return NULL;
bn_check_top(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;
+ r=BN_new();
+ if (r == NULL) return(NULL);
+ return((BIGNUM *)BN_copy(r,a));
}
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_expand_internal */
+ case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
}
#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)
a->neg=0;
}
-BN_ULONG BN_get_word(const BIGNUM *a)
+BN_ULONG BN_get_word(BIGNUM *a)
{
int i,n;
BN_ULONG ret=0;
return(NULL);
i=((n-1)/BN_BYTES)+1;
m=((n-1)%(BN_BYTES));
- ret->top=i-1;
+ ret->top=i;
while (n-- > 0)
{
l=(l<<8L)| *(s++);
return(1);
}
-int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
+int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n)
{
int i;
BN_ULONG aa,bb;
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