From: Dr. Stephen Henson Date: Fri, 14 May 1999 18:21:21 +0000 (+0000) Subject: The encoding of negative ASN1 INTEGERs and the conversion of BNs to negative X-Git-Tag: OpenSSL_0_9_3beta1~71 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=1ad2ecb66f24dc4d03e137b9f73224dc376ab5f4;p=oweals%2Fopenssl.git The encoding of negative ASN1 INTEGERs and the conversion of BNs to negative integers was completely broken. Also added a NEG_PUBKEY_BUG compilation option to compensate for public keys improperly encoded as negative integers. --- diff --git a/CHANGES b/CHANGES index 1bd0fc234f..b72f682386 100644 --- a/CHANGES +++ b/CHANGES @@ -10,6 +10,12 @@ [23-Dec-1998] down below; but in later versions, these hyphens are gone.] + *) Fix the encoding and decoding of negative ASN1 INTEGERS and conversion + to and from BNs: it was completely broken. New compilation option + NEG_PUBKEY_BUG to allow for some broken certificates that encode public + key elements as negative integers. + [Steve Henson] + *) Reorganize and speed up MD5. [Andy Polyakov ] diff --git a/crypto/asn1/a_enum.c b/crypto/asn1/a_enum.c index 365403954e..9239ecc439 100644 --- a/crypto/asn1/a_enum.c +++ b/crypto/asn1/a_enum.c @@ -60,12 +60,15 @@ #include "cryptlib.h" #include -/* Support for ASN1 ENUMERATED type: based on a_int.c */ +/* + * Code for ENUMERATED type: identical to INTEGER apart from a different tag. + * for comments on encoding see a_int.c + */ int i2d_ASN1_ENUMERATED(ASN1_ENUMERATED *a, unsigned char **pp) { int pad=0,ret,r,i,t; - unsigned char *p,*pt,*n,pb=0; + unsigned char *p,*n,pb=0; if ((a == NULL) || (a->data == NULL)) return(0); t=a->type; @@ -75,16 +78,21 @@ int i2d_ASN1_ENUMERATED(ASN1_ENUMERATED *a, unsigned char **pp) { ret=a->length; i=a->data[0]; - if ((t == V_ASN1_ENUMERATED) && (i > 127)) - { + if ((t == V_ASN1_ENUMERATED) && (i > 127)) { pad=1; pb=0; + } else if(t == V_ASN1_NEG_ENUMERATED) { + if(i>128) { + pad=1; + pb=0xFF; + } else if(i == 128) { + for(i = 1; i < a->length; i++) if(a->data[i]) { + pad=1; + pb=0xFF; + break; + } } - else if ((t == V_ASN1_NEG_ENUMERATED) && (i>128)) - { - pad=1; - pb=0xFF; - } + } ret+=pad; } r=ASN1_object_size(0,ret,V_ASN1_ENUMERATED); @@ -100,14 +108,24 @@ int i2d_ASN1_ENUMERATED(ASN1_ENUMERATED *a, unsigned char **pp) memcpy(p,a->data,(unsigned int)a->length); p+=a->length; } - else - { - n=a->data; - pt=p; - for (i=a->length; i>0; i--) - *(p++)= (*(n++)^0xFF)+1; - if (!pad) *pt|=0x80; + else { + /* Begin at the end of the encoding */ + n=a->data + a->length - 1; + p += a->length - 1; + i = a->length; + /* Copy zeros to destination as long as source is zero */ + while(!*n) { + *(p--) = 0; + n--; + i--; } + /* Complement and increment next octet */ + *(p--) = ((*(n--)) ^ 0xff) + 1; + i--; + /* Complement any octets left */ + for(;i > 0; i--) *(p--) = *(n--) ^ 0xff; + p += a->length; + } *pp=p; return(r); @@ -156,16 +174,30 @@ ASN1_ENUMERATED *d2i_ASN1_ENUMERATED(ASN1_ENUMERATED **a, unsigned char **pp, if (*p & 0x80) /* a negative number */ { ret->type=V_ASN1_NEG_ENUMERATED; - if (*p == 0xff) - { + if ((*p == 0xff) && (len != 1)) { p++; len--; - } - for (i=(int)len; i>0; i--) - *(to++)= (*(p++)^0xFF)+1; } - else - { + i = len; + p += i - 1; + to += i - 1; + while((!*p) && i) { + *(to--) = 0; + i--; + p--; + } + if(!i) { + *s = 1; + s[len] = 0; + p += len; + len++; + } else { + *(to--) = (*(p--) ^ 0xff) + 1; + i--; + for(;i > 0; i--) *(to--) = *(p--) ^ 0xff; + p += len; + } + } else { ret->type=V_ASN1_ENUMERATED; if ((*p == 0) && (len != 1)) { @@ -174,7 +206,7 @@ ASN1_ENUMERATED *d2i_ASN1_ENUMERATED(ASN1_ENUMERATED **a, unsigned char **pp, } memcpy(s,p,(int)len); p+=len; - } + } if (ret->data != NULL) Free((char *)ret->data); ret->data=s; @@ -222,7 +254,6 @@ int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v) d>>=8; } j=0; - if (v < 0) a->data[j++]=0; for (k=i-1; k >=0; k--) a->data[j++]=buf[k]; a->length=j; @@ -272,7 +303,8 @@ ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(BIGNUM *bn, ASN1_ENUMERATED *ai) ASN1err(ASN1_F_BN_TO_ASN1_ENUMERATED,ERR_R_NESTED_ASN1_ERROR); goto err; } - ret->type=V_ASN1_ENUMERATED; + if(bn->neg) ret->type = V_ASN1_NEG_ENUMERATED; + else ret->type=V_ASN1_ENUMERATED; j=BN_num_bits(bn); len=((j == 0)?0:((j/8)+1)); ret->data=(unsigned char *)Malloc(len+4); @@ -289,5 +321,6 @@ BIGNUM *ASN1_ENUMERATED_to_BN(ASN1_ENUMERATED *ai, BIGNUM *bn) if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL) ASN1err(ASN1_F_ASN1_ENUMERATED_TO_BN,ASN1_R_BN_LIB); + if(ai->type == V_ASN1_NEG_ENUMERATED) bn->neg = 1; return(ret); } diff --git a/crypto/asn1/a_int.c b/crypto/asn1/a_int.c index 6e8c7e57be..768476a0cc 100644 --- a/crypto/asn1/a_int.c +++ b/crypto/asn1/a_int.c @@ -60,10 +60,35 @@ #include "cryptlib.h" #include +/* + * This converts an ASN1 INTEGER into its DER encoding. + * The internal representation is an ASN1_STRING whose data is a big endian + * representation of the value, ignoring the sign. The sign is determined by + * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative. + * + * Positive integers are no problem: they are almost the same as the DER + * encoding, except if the first byte is >= 0x80 we need to add a zero pad. + * + * Negative integers are a bit trickier... + * The DER representation of negative integers is in 2s complement form. + * The internal form is converted by complementing each octet and finally + * adding one to the result. This can be done less messily with a little trick. + * If the internal form has trailing zeroes then they will become FF by the + * complement and 0 by the add one (due to carry) so just copy as many trailing + * zeros to the destination as there are in the source. The carry will add one + * to the last none zero octet: so complement this octet and add one and finally + * complement any left over until you get to the start of the string. + * + * Padding is a little trickier too. If the first bytes is > 0x80 then we pad + * with 0xff. However if the first byte is 0x80 and one of the following bytes + * is non-zero we pad with 0xff. The reason for this distinction is that 0x80 + * followed by optional zeros isn't padded. + */ + int i2d_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) { int pad=0,ret,r,i,t; - unsigned char *p,*pt,*n,pb=0; + unsigned char *p,*n,pb=0; if ((a == NULL) || (a->data == NULL)) return(0); t=a->type; @@ -73,16 +98,25 @@ int i2d_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) { ret=a->length; i=a->data[0]; - if ((t == V_ASN1_INTEGER) && (i > 127)) - { + if ((t == V_ASN1_INTEGER) && (i > 127)) { pad=1; pb=0; + } else if(t == V_ASN1_NEG_INTEGER) { + if(i>128) { + pad=1; + pb=0xFF; + } else if(i == 128) { + /* + * Special case: if any other bytes non zero we pad: + * otherwise we don't. + */ + for(i = 1; i < a->length; i++) if(a->data[i]) { + pad=1; + pb=0xFF; + break; + } } - else if ((t == V_ASN1_NEG_INTEGER) && (i>128)) - { - pad=1; - pb=0xFF; - } + } ret+=pad; } r=ASN1_object_size(0,ret,V_ASN1_INTEGER); @@ -98,14 +132,24 @@ int i2d_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) memcpy(p,a->data,(unsigned int)a->length); p+=a->length; } - else - { - n=a->data; - pt=p; - for (i=a->length; i>0; i--) - *(p++)= (*(n++)^0xFF)+1; - if (!pad) *pt|=0x80; + else { + /* Begin at the end of the encoding */ + n=a->data + a->length - 1; + p += a->length - 1; + i = a->length; + /* Copy zeros to destination as long as source is zero */ + while(!*n) { + *(p--) = 0; + n--; + i--; } + /* Complement and increment next octet */ + *(p--) = ((*(n--)) ^ 0xff) + 1; + i--; + /* Complement any octets left */ + for(;i > 0; i--) *(p--) = *(n--) ^ 0xff; + p += a->length; + } *pp=p; return(r); @@ -154,16 +198,105 @@ ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a, unsigned char **pp, if (*p & 0x80) /* a negative number */ { ret->type=V_ASN1_NEG_INTEGER; - if (*p == 0xff) + if ((*p == 0xff) && (len != 1)) { + p++; + len--; + } + i = len; + p += i - 1; + to += i - 1; + while((!*p) && i) { + *(to--) = 0; + i--; + p--; + } + /* Special case: if all zeros then the number will be of + * the form FF followed by n zero bytes: this corresponds to + * 1 followed by n zero bytes. We've already written n zeros + * so we just append an extra one and set the first byte to + * a 1. This is treated separately because it is the only case + * where the number of bytes is larger than len. + */ + if(!i) { + *s = 1; + s[len] = 0; + p += len; + len++; + } else { + *(to--) = (*(p--) ^ 0xff) + 1; + i--; + for(;i > 0; i--) *(to--) = *(p--) ^ 0xff; + p += len; + } + } else { + ret->type=V_ASN1_INTEGER; + if ((*p == 0) && (len != 1)) { p++; len--; } - for (i=(int)len; i>0; i--) - *(to++)= (*(p++)^0xFF)+1; + memcpy(s,p,(int)len); + p+=len; + } + + if (ret->data != NULL) Free((char *)ret->data); + ret->data=s; + ret->length=(int)len; + if (a != NULL) (*a)=ret; + *pp=p; + return(ret); +err: + ASN1err(ASN1_F_D2I_ASN1_INTEGER,i); + if ((ret != NULL) && ((a == NULL) || (*a != ret))) + ASN1_INTEGER_free(ret); + return(NULL); + } + +/* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of + * ASN1 integers: some broken software can encode a positive INTEGER + * with its MSB set as negative (it doesn't add a padding zero). + */ + +ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, unsigned char **pp, + long length) + { + ASN1_INTEGER *ret=NULL; + unsigned char *p,*to,*s; + long len; + int inf,tag,xclass; + int i; + + if ((a == NULL) || ((*a) == NULL)) + { + if ((ret=ASN1_INTEGER_new()) == NULL) return(NULL); + ret->type=V_ASN1_INTEGER; } else + ret=(*a); + + p= *pp; + inf=ASN1_get_object(&p,&len,&tag,&xclass,length); + if (inf & 0x80) + { + i=ASN1_R_BAD_OBJECT_HEADER; + goto err; + } + + if (tag != V_ASN1_INTEGER) { + i=ASN1_R_EXPECTING_AN_INTEGER; + goto err; + } + + /* We must Malloc stuff, even for 0 bytes otherwise it + * signifies a missing NULL parameter. */ + s=(unsigned char *)Malloc((int)len+1); + if (s == NULL) + { + i=ERR_R_MALLOC_FAILURE; + goto err; + } + to=s; ret->type=V_ASN1_INTEGER; if ((*p == 0) && (len != 1)) { @@ -172,7 +305,6 @@ ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a, unsigned char **pp, } memcpy(s,p,(int)len); p+=len; - } if (ret->data != NULL) Free((char *)ret->data); ret->data=s; @@ -181,7 +313,7 @@ ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a, unsigned char **pp, *pp=p; return(ret); err: - ASN1err(ASN1_F_D2I_ASN1_INTEGER,i); + ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i); if ((ret != NULL) && ((a == NULL) || (*a != ret))) ASN1_INTEGER_free(ret); return(NULL); @@ -220,7 +352,6 @@ int ASN1_INTEGER_set(ASN1_INTEGER *a, long v) d>>=8; } j=0; - if (v < 0) a->data[j++]=0; for (k=i-1; k >=0; k--) a->data[j++]=buf[k]; a->length=j; @@ -270,7 +401,8 @@ ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai) ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR); goto err; } - ret->type=V_ASN1_INTEGER; + if(bn->neg) ret->type = V_ASN1_NEG_INTEGER; + else ret->type=V_ASN1_INTEGER; j=BN_num_bits(bn); len=((j == 0)?0:((j/8)+1)); ret->data=(unsigned char *)Malloc(len+4); @@ -287,5 +419,6 @@ BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai, BIGNUM *bn) if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL) ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB); + if(ai->type == V_ASN1_NEG_INTEGER) bn->neg = 1; return(ret); } diff --git a/crypto/asn1/asn1.h b/crypto/asn1/asn1.h index 8dc61e1e63..a0a3130eff 100644 --- a/crypto/asn1/asn1.h +++ b/crypto/asn1/asn1.h @@ -518,6 +518,8 @@ int d2i_ASN1_BOOLEAN(int *a,unsigned char **pp,long length); int i2d_ASN1_INTEGER(ASN1_INTEGER *a,unsigned char **pp); ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a,unsigned char **pp, long length); +ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a,unsigned char **pp, + long length); int i2d_ASN1_ENUMERATED(ASN1_ENUMERATED *a,unsigned char **pp); ASN1_ENUMERATED *d2i_ASN1_ENUMERATED(ASN1_ENUMERATED **a,unsigned char **pp, @@ -739,6 +741,7 @@ ASN1_STRING *ASN1_pack_string(char *obj, int (*i2d)(), ASN1_OCTET_STRING **oct); #define ASN1_F_D2I_ASN1_TIME 224 #define ASN1_F_D2I_ASN1_TYPE 133 #define ASN1_F_D2I_ASN1_TYPE_BYTES 134 +#define ASN1_F_D2I_ASN1_UINTEGER 280 #define ASN1_F_D2I_ASN1_UTCTIME 135 #define ASN1_F_D2I_ASN1_UTF8STRING 266 #define ASN1_F_D2I_ASN1_VISIBLESTRING 267 diff --git a/crypto/asn1/asn1_err.c b/crypto/asn1/asn1_err.c index d3e0d0eb30..fbf73fb6da 100644 --- a/crypto/asn1/asn1_err.c +++ b/crypto/asn1/asn1_err.c @@ -115,6 +115,7 @@ static ERR_STRING_DATA ASN1_str_functs[]= {ERR_PACK(0,ASN1_F_D2I_ASN1_TIME,0), "d2i_ASN1_TIME"}, {ERR_PACK(0,ASN1_F_D2I_ASN1_TYPE,0), "d2i_ASN1_TYPE"}, {ERR_PACK(0,ASN1_F_D2I_ASN1_TYPE_BYTES,0), "d2i_ASN1_type_bytes"}, +{ERR_PACK(0,ASN1_F_D2I_ASN1_UINTEGER,0), "d2i_ASN1_UINTEGER"}, {ERR_PACK(0,ASN1_F_D2I_ASN1_UTCTIME,0), "d2i_ASN1_UTCTIME"}, {ERR_PACK(0,ASN1_F_D2I_ASN1_UTF8STRING,0), "d2i_ASN1_UTF8STRING"}, {ERR_PACK(0,ASN1_F_D2I_ASN1_VISIBLESTRING,0), "d2i_ASN1_VISIBLESTRING"}, diff --git a/crypto/asn1/d2i_dsap.c b/crypto/asn1/d2i_dsap.c index 51863a8b13..cdd7136f51 100644 --- a/crypto/asn1/d2i_dsap.c +++ b/crypto/asn1/d2i_dsap.c @@ -64,6 +64,10 @@ #include #include +#ifdef NEG_PUBKEY_BUG +#define d2i_ASN1_INTEGER d2i_ASN1_UINTEGER +#endif + DSA *d2i_DSAparams(DSA **a, unsigned char **pp, long length) { int i=ERR_R_NESTED_ASN1_ERROR; diff --git a/crypto/asn1/d2i_r_pu.c b/crypto/asn1/d2i_r_pu.c index 04cfe5671e..c4ae58b594 100644 --- a/crypto/asn1/d2i_r_pu.c +++ b/crypto/asn1/d2i_r_pu.c @@ -64,6 +64,10 @@ #include #include +#ifdef NEG_PUBKEY_BUG +#define d2i_ASN1_INTEGER d2i_ASN1_UINTEGER +#endif + RSA *d2i_RSAPublicKey(RSA **a, unsigned char **pp, long length) { int i=ASN1_R_PARSING; diff --git a/crypto/asn1/d2i_s_pu.c b/crypto/asn1/d2i_s_pu.c index 2b1bf638c1..94ea1c313b 100644 --- a/crypto/asn1/d2i_s_pu.c +++ b/crypto/asn1/d2i_s_pu.c @@ -66,6 +66,10 @@ #include #include +#ifdef NEG_PUBKEY_BUG +#define d2i_ASN1_INTEGER d2i_ASN1_UINTEGER +#endif + DSA *d2i_DSAPublicKey(DSA **a, unsigned char **pp, long length) { int i=ASN1_R_PARSING; diff --git a/util/libeay.num b/util/libeay.num index 01299b1f7a..7be174acdf 100755 --- a/util/libeay.num +++ b/util/libeay.num @@ -1624,3 +1624,4 @@ X509V3_EXT_add_list 1648 EVP_CIPHER_type 1649 EVP_PBE_CipherInit 1650 X509V3_add_value_bool_nf 1651 +d2i_ASN1_UINTEGER 1652