X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_lib.c;h=77a9e3225454c2428fee73fdcc6a85fa310a3732;hp=df79d6e3380d38259c0d3c91dfcffd18345740e0;hb=12593e6f45b146ac8f368e743238f67f22a52c80;hpb=dd8dec69b825c9fdafc26a200961702d850496b5

diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index df79d6e338..77a9e32254 100644
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -56,6 +56,13 @@
  * [including the GNU Public Licence.]
  */
 
+#ifndef BN_DEBUG
+# undef NDEBUG /* avoid conflicting definitions */
+# define NDEBUG
+#endif
+
+#include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"
@@ -71,14 +78,14 @@ const char *BN_version="Big Number" OPENSSL_VERSION_PTEXT;
  * 7 - 128 == 4096
  * 8 - 256 == 8192
  */
-OPENSSL_GLOBAL int bn_limit_bits=0;
-OPENSSL_GLOBAL int bn_limit_num=8;        /* (1<<bn_limit_bits) */
-OPENSSL_GLOBAL int bn_limit_bits_low=0;
-OPENSSL_GLOBAL int bn_limit_num_low=8;    /* (1<<bn_limit_bits_low) */
-OPENSSL_GLOBAL int bn_limit_bits_high=0;
-OPENSSL_GLOBAL int bn_limit_num_high=8;   /* (1<<bn_limit_bits_high) */
-OPENSSL_GLOBAL int bn_limit_bits_mont=0;
-OPENSSL_GLOBAL int bn_limit_num_mont=8;   /* (1<<bn_limit_bits_mont) */
+static int bn_limit_bits=0;
+static int bn_limit_num=8;        /* (1<<bn_limit_bits) */
+static int bn_limit_bits_low=0;
+static int bn_limit_num_low=8;    /* (1<<bn_limit_bits_low) */
+static int bn_limit_bits_high=0;
+static int bn_limit_num_high=8;   /* (1<<bn_limit_bits_high) */
+static int bn_limit_bits_mont=0;
+static int bn_limit_num_mont=8;   /* (1<<bn_limit_bits_mont) */
 
 void BN_set_params(int mult, int high, int low, int mont)
 	{
@@ -121,7 +128,7 @@ int BN_get_params(int which)
 	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};
@@ -244,14 +251,8 @@ int BN_num_bits(const BIGNUM *a)
 
 	if (a->top == 0) return(0);
 	l=a->d[a->top-1];
+	assert(l != 0);
 	i=(a->top-1)*BN_BITS2;
-	if (l == 0)
-		{
-#if !defined(NO_STDIO) && !defined(WIN16)
-		fprintf(stderr,"BAD TOP VALUE\n");
-#endif
-		abort();
-		}
 	return(i+BN_num_bits_word(l));
 	}
 
@@ -262,24 +263,24 @@ void BN_clear_free(BIGNUM *a)
 	if (a == NULL) return;
 	if (a->d != NULL)
 		{
-		memset(a->d,0,a->max*sizeof(a->d[0]));
+		memset(a->d,0,a->dmax*sizeof(a->d[0]));
 		if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
-			Free(a->d);
+			OPENSSL_free(a->d);
 		}
 	i=BN_get_flags(a,BN_FLG_MALLOCED);
 	memset(a,0,sizeof(BIGNUM));
 	if (i)
-		Free(a);
+		OPENSSL_free(a);
 	}
 
 void BN_free(BIGNUM *a)
 	{
 	if (a == NULL) return;
 	if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
-		Free(a->d);
+		OPENSSL_free(a->d);
 	a->flags|=BN_FLG_FREE; /* REMOVE? */
 	if (a->flags & BN_FLG_MALLOCED)
-		Free(a);
+		OPENSSL_free(a);
 	}
 
 void BN_init(BIGNUM *a)
@@ -291,7 +292,7 @@ BIGNUM *BN_new(void)
 	{
 	BIGNUM *ret;
 
-	if ((ret=(BIGNUM *)Malloc(sizeof(BIGNUM))) == NULL)
+	if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
 		{
 		BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
 		return(NULL);
@@ -299,208 +300,183 @@ BIGNUM *BN_new(void)
 	ret->flags=BN_FLG_MALLOCED;
 	ret->top=0;
 	ret->neg=0;
-	ret->max=0;
+	ret->dmax=0;
 	ret->d=NULL;
 	return(ret);
 	}
 
-
-BN_CTX *BN_CTX_new(void)
+/* 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)
 	{
-	BN_CTX *ret;
+	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;
+		}
 
-	ret=(BN_CTX *)Malloc(sizeof(BN_CTX));
-	if (ret == NULL)
+	bn_check_top(b);	
+	if (BN_get_flags(b,BN_FLG_STATIC_DATA))
 		{
-		BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
+		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)
+		{
+		for (i=b->top>>2; i>0; i--,A+=4,B+=4)
+			{
+			/*
+			 * 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;
+			}
+		switch (b->top&3)
+			{
+		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 */
+			;
+			}
+		}
 
-	BN_CTX_init(ret);
-	ret->flags=BN_FLG_MALLOCED;
-	return(ret);
+#else
+	memset(A,0,sizeof(BN_ULONG)*(words+1));
+	memcpy(A,b->d,sizeof(b->d[0])*b->top);
+#endif
+		
+	return(a);
 	}
 
-void BN_CTX_init(BN_CTX *ctx)
-	{
-	memset(ctx,0,sizeof(BN_CTX));
-	ctx->tos=0;
-	ctx->flags=0;
-	}
+/* 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.
+ */
 
-void BN_CTX_free(BN_CTX *c)
+BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
 	{
-	int i;
+	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 = bn_expand_internal(b, words);
 
-	if(c == NULL)
-	    return;
+		if (a)
+			{
+			r = BN_new();
+			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);
+				}
+			}
+		/* If a == NULL, there was an error in allocation in
+		   bn_expand_internal(), and NULL should be returned */
+		}
+	else
+		{
+		r = BN_dup(b);
+		}
 
-	for (i=0; i<BN_CTX_NUM; i++)
-		BN_clear_free(&(c->bn[i]));
-	if (c->flags & BN_FLG_MALLOCED)
-		Free(c);
+	return r;
 	}
 
 /* This is an internal function that should not be used in applications.
- * It ensures that 'b' has enough room for a 'bits' bit number.  It is
- * mostly used by the various BIGNUM routines.  If there is an error,
- * NULL is returned. if not, 'b' is returned.
- */
+ * 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,*a;
-	const BN_ULONG *B;
+	BN_ULONG *A;
 	int i;
 
-	bn_check_top(b);
-
-	if (words > b->max)
+	if (words > b->dmax)
 		{
-		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);
-			return(NULL);
-			}
-		a=A=(BN_ULONG *)Malloc(sizeof(BN_ULONG)*(words+1));
-		if (A == NULL)
-			{
-			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
- * particulare 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 optimiser 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)
-				{
-				/*
-				 * 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;
-				}
-			switch (b->top&3)
-				{
-				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
-			Free(b->d);
-			}
-
-		b->d=a;
-		b->max=words;
-
-		/* Now need to zero any data between b->top and b->max */
+		BN_ULONG *a = bn_expand_internal(b, words);
 
-		A= &(b->d[b->top]);
-		for (i=(b->max - b->top)>>3; i>0; i--,A+=8)
+		if (a)
 			{
-			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=(b->max - 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);
+			if (b->d)
+				OPENSSL_free(b->d);
 			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;} */
-
+			b->dmax=words;
+			}
+		else
+			b = NULL;
 		}
-	return(b);
+	
+	/* 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)
@@ -528,7 +504,7 @@ 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);
@@ -542,15 +518,44 @@ BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
 	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)
-		memset(a->d,0,a->max*sizeof(a->d[0]));
+		memset(a->d,0,a->dmax*sizeof(a->d[0]));
 	a->top=0;
 	a->neg=0;
 	}
 
-BN_ULONG BN_get_word(BIGNUM *a)
+BN_ULONG BN_get_word(const BIGNUM *a)
 	{
 	int i,n;
 	BN_ULONG ret=0;
@@ -598,7 +603,6 @@ int BN_set_word(BIGNUM *a, BN_ULONG w)
 	return(1);
 	}
 
-/* ignore negative */
 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
 	{
 	unsigned int i,m;
@@ -619,6 +623,7 @@ BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
 	i=((n-1)/BN_BYTES)+1;
 	m=((n-1)%(BN_BYTES));
 	ret->top=i;
+	ret->neg=0;
 	while (n-- > 0)
 		{
 		l=(l<<8L)| *(s++);
@@ -773,7 +778,7 @@ int BN_mask_bits(BIGNUM *a, int n)
 	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;
@@ -790,3 +795,34 @@ int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n)
 	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);
+	}