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 1bd0fc2..b72f682 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 <appro@fy.chalmers.se>]
diff --git a/crypto/asn1/a_enum.c b/crypto/asn1/a_enum.c
index 3654039..9239ecc 100644
--- a/crypto/asn1/a_enum.c
+++ b/crypto/asn1/a_enum.c
@@ -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 @@
{
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 @@
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 @@
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 @@
}
memcpy(s,p,(int)len);
p+=len;
- }
+ }
if (ret->data != NULL) Free((char *)ret->data);
ret->data=s;
@@ -222,7 +254,6 @@
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 @@
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 @@
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 6e8c7e5..768476a 100644
--- a/crypto/asn1/a_int.c
+++ b/crypto/asn1/a_int.c
@@ -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 @@
{
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 @@
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 @@
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 @@
}
memcpy(s,p,(int)len);
p+=len;
- }
+ }
if (ret->data != NULL) Free((char *)ret->data);
ret->data=s;
@@ -187,6 +252,73 @@
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 @@
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 @@
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 @@
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 8dc61e1..a0a3130 100644
--- a/crypto/asn1/asn1.h
+++ b/crypto/asn1/asn1.h
@@ -518,6 +518,8 @@
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 @@
#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 d3e0d0e..fbf73fb 100644
--- a/crypto/asn1/asn1_err.c
+++ b/crypto/asn1/asn1_err.c
@@ -115,6 +115,7 @@
{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 51863a8..cdd7136 100644
--- a/crypto/asn1/d2i_dsap.c
+++ b/crypto/asn1/d2i_dsap.c
@@ -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;
diff --git a/crypto/asn1/d2i_r_pu.c b/crypto/asn1/d2i_r_pu.c
index 04cfe56..c4ae58b 100644
--- a/crypto/asn1/d2i_r_pu.c
+++ b/crypto/asn1/d2i_r_pu.c
@@ -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;
diff --git a/crypto/asn1/d2i_s_pu.c b/crypto/asn1/d2i_s_pu.c
index 2b1bf63..94ea1c3 100644
--- a/crypto/asn1/d2i_s_pu.c
+++ b/crypto/asn1/d2i_s_pu.c
@@ -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;
diff --git a/util/libeay.num b/util/libeay.num
index 01299b1..7be174a 100755
--- a/util/libeay.num
+++ b/util/libeay.num
@@ -1624,3 +1624,4 @@
EVP_CIPHER_type 1649
EVP_PBE_CipherInit 1650
X509V3_add_value_bool_nf 1651
+d2i_ASN1_UINTEGER 1652
