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The encoding of negative ASN1 INTEGERs and the conversion of BNs to negative

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integers was completely broken. Also added a NEG_PUBKEY_BUG compilation option
to compensate for public keys improperly encoded as negative integers.
This commit is contained in:
Dr. Stephen Henson 1999-05-14 18:21:21 +00:00
parent 2a82c7cf25
commit 1ad2ecb66f
9 changed files with 240 additions and 51 deletions
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6
CHANGES
View File

@ -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 <appro@fy.chalmers.se>]

85
crypto/asn1/a_enum.c
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@ -60,12 +60,15 @@
#include "cryptlib.h"
#include <openssl/asn1.h>
/* 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);
}

183
crypto/asn1/a_int.c
View File

@ -60,10 +60,35 @@
#include "cryptlib.h"
#include <openssl/asn1.h>
/*
* 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 +198,37 @@ 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--;
}
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--;
}
/* 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))
{
@ -172,7 +237,7 @@ 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;
@ -187,6 +252,73 @@ err:
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))
{
p++;
len--;
}
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_UINTEGER,i);
if ((ret != NULL) && ((a == NULL) || (*a != ret)))
ASN1_INTEGER_free(ret);
return(NULL);
}
int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
{
int i,j,k;
@ -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);
}

3
crypto/asn1/asn1.h
View File

@ -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

1
crypto/asn1/asn1_err.c
View File

@ -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"},

4
crypto/asn1/d2i_dsap.c
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@ -64,6 +64,10 @@
#include <openssl/objects.h>
#include <openssl/asn1_mac.h>
#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;

4
crypto/asn1/d2i_r_pu.c
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@ -64,6 +64,10 @@
#include <openssl/objects.h>
#include <openssl/asn1_mac.h>
#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;

4
crypto/asn1/d2i_s_pu.c
View File

@ -66,6 +66,10 @@
#include <openssl/objects.h>
#include <openssl/asn1_mac.h>
#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;

1
util/libeay.num
View File

@ -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