X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_lib.c;h=77a9e3225454c2428fee73fdcc6a85fa310a3732;hp=b693c7e0c07b8cd493b1b18f81c1291495ba4218;hb=12593e6f45b146ac8f368e743238f67f22a52c80;hpb=2d978cbd30f60f9e9ddaf743d818ef66ec217f47 diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c index b693c7e0c0..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 +#include #include #include "cryptlib.h" #include "bn_lcl.h" @@ -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)); } @@ -304,166 +305,178 @@ BIGNUM *BN_new(void) return(ret); } -/* 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) +/* 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_ULONG *A,*a; + BN_ULONG *A,*a = NULL; const BN_ULONG *B; int i; - bn_check_top(b); + if (words > (INT_MAX/(4*BN_BITS2))) + { + BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG); + return NULL; + } - if (words > b->dmax) + 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) { - bn_check_top(b); - if (BN_get_flags(b,BN_FLG_STATIC_DATA)) + 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) { - BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA); - return(NULL); + /* + * 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:-) + * + * + */ + 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; } - a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1)); - if (A == NULL) + switch (b->top&3) { - BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE); - return(NULL); + 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 */ + ; } -#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. - * - * - */ - 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) + 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; + + /* 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 (a) + { + r = BN_new(); + if (r) { - /* - * 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:-) - * - * - */ - 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; + r->top = b->top; + r->dmax = words; + r->neg = b->neg; + r->d = a; } - switch (b->top&3) + else { - 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 */ + /* r == NULL, BN_new failure */ + OPENSSL_free(a); } -#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); + } - b->d=a; - b->dmax=words; + return r; + } - /* Now need to zero any data between b->top and b->max */ +/* This is an internal function that should not be used in applications. + * 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. */ - A= &(b->d[b->top]); - for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8) +BIGNUM *bn_expand2(BIGNUM *b, int words) + { + BN_ULONG *A; + int i; + + if (words > b->dmax) + { + BN_ULONG *a = bn_expand_internal(b, words); + + 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->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); + 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; idmax=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; } - return(b); + 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) @@ -491,7 +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); @@ -505,6 +518,35 @@ 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) @@ -513,7 +555,7 @@ void BN_clear(BIGNUM *a) 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; @@ -561,7 +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; @@ -582,6 +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++); @@ -736,7 +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; @@ -753,3 +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); + }