ref: 844bbecadb3a4263a183ce03021849ac41cbd20f
dir: /sys/src/libsec/port/x509.c/
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
/* ANSI offsetof, backwards. */
#define OFFSETOF(a, b) offsetof(b, a)
/*=============================================================*/
/* general ASN1 declarations and parsing
*
* For now, this is used only for extracting the key from an
* X509 certificate, so the entire collection is hidden. But
* someday we should probably make the functions visible and
* give them their own man page.
*/
typedef struct Elem Elem;
typedef struct Tag Tag;
typedef struct Value Value;
typedef struct Bytes Bytes;
typedef struct Ints Ints;
typedef struct Bits Bits;
typedef struct Elist Elist;
/* tag classes */
#define Universal 0
#define Context 0x80
/* universal tags */
#define BOOLEAN 1
#define INTEGER 2
#define BIT_STRING 3
#define OCTET_STRING 4
#define NULLTAG 5
#define OBJECT_ID 6
#define ObjectDescriptor 7
#define EXTERNAL 8
#define REAL 9
#define ENUMERATED 10
#define EMBEDDED_PDV 11
#define UTF8String 12
#define SEQUENCE 16 /* also SEQUENCE OF */
#define SETOF 17 /* also SETOF OF */
#define NumericString 18
#define PrintableString 19
#define TeletexString 20
#define VideotexString 21
#define IA5String 22
#define UTCTime 23
#define GeneralizedTime 24
#define GraphicString 25
#define VisibleString 26
#define GeneralString 27
#define UniversalString 28
#define BMPString 30
struct Bytes {
int len;
uchar data[1];
};
struct Ints {
int len;
int data[1];
};
struct Bits {
int len; /* number of bytes */
int unusedbits; /* unused bits in last byte */
uchar data[1]; /* most-significant bit first */
};
struct Tag {
int class;
int num;
};
enum { VBool, VInt, VOctets, VBigInt, VReal, VOther,
VBitString, VNull, VEOC, VObjId, VString, VSeq, VSet };
struct Value {
int tag; /* VBool, etc. */
union {
int boolval;
int intval;
Bytes* octetsval;
Bytes* bigintval;
Bytes* realval; /* undecoded; hardly ever used */
Bytes* otherval;
Bits* bitstringval;
Ints* objidval;
char* stringval;
Elist* seqval;
Elist* setval;
} u; /* (Don't use anonymous unions, for ease of porting) */
};
struct Elem {
Tag tag;
Value val;
};
struct Elist {
Elist* tl;
Elem hd;
};
/* decoding errors */
enum { ASN_OK, ASN_ESHORT, ASN_ETOOBIG, ASN_EVALLEN,
ASN_ECONSTR, ASN_EPRIM, ASN_EINVAL, ASN_EUNIMPL };
/* here are the functions to consider making extern someday */
static Bytes* newbytes(int len);
static Bytes* makebytes(uchar* buf, int len);
static void freebytes(Bytes* b);
static Bytes* catbytes(Bytes* b1, Bytes* b2);
static Ints* newints(int len);
static Ints* makeints(int* buf, int len);
static void freeints(Ints* b);
static Bits* newbits(int len);
static Bits* makebits(uchar* buf, int len, int unusedbits);
static void freebits(Bits* b);
static Elist* mkel(Elem e, Elist* tail);
static void freeelist(Elist* el);
static int elistlen(Elist* el);
static int is_seq(Elem* pe, Elist** pseq);
static int is_set(Elem* pe, Elist** pset);
static int is_int(Elem* pe, int* pint);
static int is_bigint(Elem* pe, Bytes** pbigint);
static int is_bitstring(Elem* pe, Bits** pbits);
static int is_octetstring(Elem* pe, Bytes** poctets);
static int is_oid(Elem* pe, Ints** poid);
static int is_string(Elem* pe, char** pstring);
static int is_time(Elem* pe, char** ptime);
static int decode(uchar* a, int alen, Elem* pelem);
static int decode_seq(uchar* a, int alen, Elist** pelist);
static int decode_value(uchar* a, int alen, int kind, int isconstr, Value* pval);
static int encode(Elem e, Bytes** pbytes);
static int oid_lookup(Ints* o, Ints** tab);
static void freevalfields(Value* v);
static mpint *asn1mpint(Elem *e);
#define TAG_MASK 0x1F
#define CONSTR_MASK 0x20
#define CLASS_MASK 0xC0
#define MAXOBJIDLEN 20
static int ber_decode(uchar** pp, uchar* pend, Elem* pelem);
static int tag_decode(uchar** pp, uchar* pend, Tag* ptag, int* pisconstr);
static int length_decode(uchar** pp, uchar* pend, int* plength);
static int value_decode(uchar** pp, uchar* pend, int length, int kind, int isconstr, Value* pval);
static int int_decode(uchar** pp, uchar* pend, int count, int unsgned, int* pint);
static int uint7_decode(uchar** pp, uchar* pend, int* pint);
static int octet_decode(uchar** pp, uchar* pend, int length, int isconstr, Bytes** pbytes);
static int seq_decode(uchar** pp, uchar* pend, int length, int isconstr, Elist** pelist);
static int enc(uchar** pp, Elem e, int lenonly);
static int val_enc(uchar** pp, Elem e, int *pconstr, int lenonly);
static void uint7_enc(uchar** pp, int num, int lenonly);
static void int_enc(uchar** pp, int num, int unsgned, int lenonly);
static void *
emalloc(int n)
{
void *p;
if(n==0)
n=1;
p = malloc(n);
if(p == nil)
sysfatal("out of memory");
memset(p, 0, n);
setmalloctag(p, getcallerpc(&n));
return p;
}
static char*
estrdup(char *s)
{
char *d;
int n;
n = strlen(s)+1;
d = emalloc(n);
memmove(d, s, n);
return d;
}
/*
* Decode a[0..len] as a BER encoding of an ASN1 type.
* The return value is one of ASN_OK, etc.
* Depending on the error, the returned elem may or may not
* be nil.
*/
static int
decode(uchar* a, int alen, Elem* pelem)
{
uchar* p = a;
return ber_decode(&p, &a[alen], pelem);
}
/*
* Like decode, but continue decoding after first element
* of array ends.
*/
static int
decode_seq(uchar* a, int alen, Elist** pelist)
{
uchar* p = a;
return seq_decode(&p, &a[alen], -1, 1, pelist);
}
/*
* Decode the whole array as a BER encoding of an ASN1 value,
* (i.e., the part after the tag and length).
* Assume the value is encoded as universal tag "kind".
* The constr arg is 1 if the value is constructed, 0 if primitive.
* If there's an error, the return string will contain the error.
* Depending on the error, the returned value may or may not
* be nil.
*/
static int
decode_value(uchar* a, int alen, int kind, int isconstr, Value* pval)
{
uchar* p = a;
return value_decode(&p, &a[alen], alen, kind, isconstr, pval);
}
/*
* All of the following decoding routines take arguments:
* uchar **pp;
* uchar *pend;
* Where parsing is supposed to start at **pp, and when parsing
* is done, *pp is updated to point at next char to be parsed.
* The pend pointer is just past end of string; an error should
* be returned parsing hasn't finished by then.
*
* The returned int is ASN_OK if all went fine, else ASN_ESHORT, etc.
* The remaining argument(s) are pointers to where parsed entity goes.
*/
/* Decode an ASN1 'Elem' (tag, length, value) */
static int
ber_decode(uchar** pp, uchar* pend, Elem* pelem)
{
int err;
int isconstr;
int length;
Tag tag;
Value val;
err = tag_decode(pp, pend, &tag, &isconstr);
if(err == ASN_OK) {
err = length_decode(pp, pend, &length);
if(err == ASN_OK) {
if(tag.class == Universal)
err = value_decode(pp, pend, length, tag.num, isconstr, &val);
else
err = value_decode(pp, pend, length, OCTET_STRING, 0, &val);
if(err == ASN_OK) {
pelem->tag = tag;
pelem->val = val;
}
}
}
return err;
}
/* Decode a tag field */
static int
tag_decode(uchar** pp, uchar* pend, Tag* ptag, int* pisconstr)
{
int err;
int v;
uchar* p;
err = ASN_OK;
p = *pp;
if(pend-p >= 2) {
v = *p++;
ptag->class = v&CLASS_MASK;
if(v&CONSTR_MASK)
*pisconstr = 1;
else
*pisconstr = 0;
v &= TAG_MASK;
if(v == TAG_MASK)
err = uint7_decode(&p, pend, &v);
ptag->num = v;
}
else
err = ASN_ESHORT;
*pp = p;
return err;
}
/* Decode a length field */
static int
length_decode(uchar** pp, uchar* pend, int* plength)
{
int err;
int num;
int v;
uchar* p;
err = ASN_OK;
num = 0;
p = *pp;
if(p < pend) {
v = *p++;
if(v&0x80)
err = int_decode(&p, pend, v&0x7F, 1, &num);
else
num = v;
}
else
err = ASN_ESHORT;
*pp = p;
*plength = num;
return err;
}
/* Decode a value field */
static int
value_decode(uchar** pp, uchar* pend, int length, int kind, int isconstr, Value* pval)
{
int err;
Bytes* va;
int num;
int bitsunused;
int subids[MAXOBJIDLEN];
int isubid;
Elist* vl;
uchar* p;
uchar* pe;
err = ASN_OK;
p = *pp;
if(length == -1) { /* "indefinite" length spec */
if(!isconstr)
err = ASN_EINVAL;
}
else if(p + length > pend)
err = ASN_EVALLEN;
if(err != ASN_OK)
return err;
switch(kind) {
case 0:
/* marker for end of indefinite constructions */
if(length == 0)
pval->tag = VNull;
else
err = ASN_EINVAL;
break;
case BOOLEAN:
if(isconstr)
err = ASN_ECONSTR;
else if(length != 1)
err = ASN_EVALLEN;
else {
pval->tag = VBool;
pval->u.boolval = (*p++ != 0);
}
break;
case INTEGER:
case ENUMERATED:
if(isconstr)
err = ASN_ECONSTR;
else if(length <= 4) {
err = int_decode(&p, pend, length, 0, &num);
if(err == ASN_OK) {
pval->tag = VInt;
pval->u.intval = num;
}
}
else {
pval->tag = VBigInt;
pval->u.bigintval = makebytes(p, length);
p += length;
}
break;
case BIT_STRING:
pval->tag = VBitString;
if(isconstr) {
if(length == -1 && p + 2 <= pend && *p == 0 && *(p+1) ==0) {
pval->u.bitstringval = makebits(0, 0, 0);
p += 2;
}
else /* TODO: recurse and concat results */
err = ASN_EUNIMPL;
}
else {
if(length < 2) {
if(length == 1 && *p == 0) {
pval->u.bitstringval = makebits(0, 0, 0);
p++;
}
else
err = ASN_EINVAL;
}
else {
bitsunused = *p;
if(bitsunused > 7)
err = ASN_EINVAL;
else if(length > 0x0FFFFFFF)
err = ASN_ETOOBIG;
else {
pval->u.bitstringval = makebits(p+1, length-1, bitsunused);
p += length;
}
}
}
break;
case OCTET_STRING:
case ObjectDescriptor:
err = octet_decode(&p, pend, length, isconstr, &va);
if(err == ASN_OK) {
pval->tag = VOctets;
pval->u.octetsval = va;
}
break;
case NULLTAG:
if(isconstr)
err = ASN_ECONSTR;
else if(length != 0)
err = ASN_EVALLEN;
else
pval->tag = VNull;
break;
case OBJECT_ID:
if(isconstr)
err = ASN_ECONSTR;
else if(length == 0)
err = ASN_EVALLEN;
else {
isubid = 0;
pe = p+length;
while(p < pe && isubid < MAXOBJIDLEN) {
err = uint7_decode(&p, pend, &num);
if(err != ASN_OK)
break;
if(isubid == 0) {
subids[isubid++] = num / 40;
subids[isubid++] = num % 40;
}
else
subids[isubid++] = num;
}
if(err == ASN_OK) {
if(p != pe)
err = ASN_EVALLEN;
else {
pval->tag = VObjId;
pval->u.objidval = makeints(subids, isubid);
}
}
}
break;
case EXTERNAL:
case EMBEDDED_PDV:
/* TODO: parse this internally */
if(p+length > pend)
err = ASN_EVALLEN;
else {
pval->tag = VOther;
pval->u.otherval = makebytes(p, length);
p += length;
}
break;
case REAL:
/* Let the application decode */
if(isconstr)
err = ASN_ECONSTR;
else if(p+length > pend)
err = ASN_EVALLEN;
else {
pval->tag = VReal;
pval->u.realval = makebytes(p, length);
p += length;
}
break;
case SEQUENCE:
err = seq_decode(&p, pend, length, isconstr, &vl);
if(err == ASN_OK) {
pval->tag = VSeq ;
pval->u.seqval = vl;
}
break;
case SETOF:
err = seq_decode(&p, pend, length, isconstr, &vl);
if(err == ASN_OK) {
pval->tag = VSet;
pval->u.setval = vl;
}
break;
case UTF8String:
case NumericString:
case PrintableString:
case TeletexString:
case VideotexString:
case IA5String:
case UTCTime:
case GeneralizedTime:
case GraphicString:
case VisibleString:
case GeneralString:
case UniversalString:
case BMPString:
/* TODO: figure out when character set conversion is necessary */
err = octet_decode(&p, pend, length, isconstr, &va);
if(err == ASN_OK) {
pval->tag = VString;
pval->u.stringval = (char*)emalloc(va->len+1);
memmove(pval->u.stringval, va->data, va->len);
pval->u.stringval[va->len] = 0;
free(va);
}
break;
default:
if(p+length > pend)
err = ASN_EVALLEN;
else {
pval->tag = VOther;
pval->u.otherval = makebytes(p, length);
p += length;
}
break;
}
*pp = p;
return err;
}
/*
* Decode an int in format where count bytes are
* concatenated to form value.
* Although ASN1 allows any size integer, we return
* an error if the result doesn't fit in a 32-bit int.
* If unsgned is not set, make sure to propagate sign bit.
*/
static int
int_decode(uchar** pp, uchar* pend, int count, int unsgned, int* pint)
{
int err;
int num;
uchar* p;
p = *pp;
err = ASN_OK;
num = 0;
if(p+count <= pend) {
if((count > 4) || (unsgned && count == 4 && (*p&0x80)))
err = ASN_ETOOBIG;
else {
if(!unsgned && count > 0 && count < 4 && (*p&0x80))
num = -1; /* set all bits, initially */
while(count--)
num = (num << 8)|(*p++);
}
}
else
err = ASN_ESHORT;
*pint = num;
*pp = p;
return err;
}
/*
* Decode an unsigned int in format where each
* byte except last has high bit set, and remaining
* seven bits of each byte are concatenated to form value.
* Although ASN1 allows any size integer, we return
* an error if the result doesn't fit in a 32 bit int.
*/
static int
uint7_decode(uchar** pp, uchar* pend, int* pint)
{
int err;
int num;
int more;
int v;
uchar* p;
p = *pp;
err = ASN_OK;
num = 0;
more = 1;
while(more && p < pend) {
v = *p++;
if(num&0x7F000000) {
err = ASN_ETOOBIG;
break;
}
num <<= 7;
more = v&0x80;
num |= (v&0x7F);
}
if(p == pend)
err = ASN_ESHORT;
*pint = num;
*pp = p;
return err;
}
/*
* Decode an octet string, recursively if isconstr.
* We've already checked that length==-1 implies isconstr==1,
* and otherwise that specified length fits within (*pp..pend)
*/
static int
octet_decode(uchar** pp, uchar* pend, int length, int isconstr, Bytes** pbytes)
{
int err;
uchar* p;
Bytes* ans;
Bytes* newans;
uchar* pstart;
uchar* pold;
Elem elem;
err = ASN_OK;
p = *pp;
ans = nil;
if(length >= 0 && !isconstr) {
ans = makebytes(p, length);
p += length;
}
else {
/* constructed, either definite or indefinite length */
pstart = p;
for(;;) {
if(length >= 0 && p >= pstart + length) {
if(p != pstart + length)
err = ASN_EVALLEN;
break;
}
pold = p;
err = ber_decode(&p, pend, &elem);
if(err != ASN_OK)
break;
switch(elem.val.tag) {
case VOctets:
newans = catbytes(ans, elem.val.u.octetsval);
freevalfields(&elem.val);
freebytes(ans);
ans = newans;
break;
case VEOC:
if(length == -1)
goto cloop_done;
/* no break */
default:
freevalfields(&elem.val);
p = pold;
err = ASN_EINVAL;
goto cloop_done;
}
}
cloop_done:
if(err != ASN_OK){
freebytes(ans);
ans = nil;
}
}
*pp = p;
*pbytes = ans;
return err;
}
/*
* Decode a sequence or set.
* We've already checked that length==-1 implies isconstr==1,
* and otherwise that specified length fits within (*p..pend)
*/
static int
seq_decode(uchar** pp, uchar* pend, int length, int isconstr, Elist** pelist)
{
int err;
uchar* p;
uchar* pstart;
uchar* pold;
Elist* ans;
Elem elem;
Elist* lve;
Elist* lveold;
err = ASN_OK;
ans = nil;
p = *pp;
if(!isconstr)
err = ASN_EPRIM;
else {
/* constructed, either definite or indefinite length */
lve = nil;
pstart = p;
for(;;) {
if(length >= 0 && p >= pstart + length) {
if(p != pstart + length)
err = ASN_EVALLEN;
break;
}
pold = p;
err = ber_decode(&p, pend, &elem);
if(err != ASN_OK)
break;
if(elem.val.tag == VEOC) {
if(length != -1) {
p = pold;
err = ASN_EINVAL;
}
break;
}
else
lve = mkel(elem, lve);
}
if(err != ASN_OK)
freeelist(lve);
else {
/* reverse back to original order */
while(lve != nil) {
lveold = lve;
lve = lve->tl;
lveold->tl = ans;
ans = lveold;
}
}
}
*pp = p;
*pelist = ans;
return err;
}
/*
* Encode e by BER rules, putting answer in *pbytes.
* This is done by first calling enc with lenonly==1
* to get the length of the needed buffer,
* then allocating the buffer and using enc again to fill it up.
*/
static int
encode(Elem e, Bytes** pbytes)
{
uchar* p;
Bytes* ans;
int err;
uchar uc;
p = &uc;
err = enc(&p, e, 1);
if(err == ASN_OK) {
ans = newbytes(p-&uc);
p = ans->data;
err = enc(&p, e, 0);
*pbytes = ans;
}
return err;
}
/*
* The various enc functions take a pointer to a pointer
* into a buffer, and encode their entity starting there,
* updating the pointer afterwards.
* If lenonly is 1, only the pointer update is done,
* allowing enc to be called first to calculate the needed
* buffer length.
* If lenonly is 0, it is assumed that the answer will fit.
*/
static int
enc(uchar** pp, Elem e, int lenonly)
{
int err;
int vlen;
int constr;
Tag tag;
int v;
int ilen;
uchar* p;
uchar* psave;
p = *pp;
err = val_enc(&p, e, &constr, 1);
if(err != ASN_OK)
return err;
vlen = p - *pp;
p = *pp;
tag = e.tag;
v = tag.class|constr;
if(tag.num < 31) {
if(!lenonly)
*p = (v|tag.num);
p++;
}
else {
if(!lenonly)
*p = (v|31);
p++;
if(tag.num < 0)
return ASN_EINVAL;
uint7_enc(&p, tag.num, lenonly);
}
if(vlen < 0x80) {
if(!lenonly)
*p = vlen;
p++;
}
else {
psave = p;
int_enc(&p, vlen, 1, 1);
ilen = p-psave;
p = psave;
if(!lenonly) {
*p++ = (0x80 | ilen);
int_enc(&p, vlen, 1, 0);
}
else
p += 1 + ilen;
}
if(!lenonly)
val_enc(&p, e, &constr, 0);
else
p += vlen;
*pp = p;
return err;
}
static int
val_enc(uchar** pp, Elem e, int *pconstr, int lenonly)
{
int err;
uchar* p;
int kind;
int cl;
int v;
Bytes* bb = nil;
Bits* bits;
Ints* oid;
int k;
Elist* el;
char* s;
p = *pp;
err = ASN_OK;
kind = e.tag.num;
cl = e.tag.class;
*pconstr = 0;
if(cl != Universal) {
switch(e.val.tag) {
case VBool:
kind = BOOLEAN;
break;
case VInt:
kind = INTEGER;
break;
case VBigInt:
kind = INTEGER;
break;
case VOctets:
kind = OCTET_STRING;
break;
case VReal:
kind = REAL;
break;
case VOther:
kind = OCTET_STRING;
break;
case VBitString:
kind = BIT_STRING;
break;
case VNull:
kind = NULLTAG;
break;
case VObjId:
kind = OBJECT_ID;
break;
case VString:
kind = UniversalString;
break;
case VSeq:
kind = SEQUENCE;
break;
case VSet:
kind = SETOF;
break;
}
}
switch(kind) {
case BOOLEAN:
if(is_int(&e, &v)) {
if(v != 0)
v = 255;
int_enc(&p, v, 1, lenonly);
}
else
err = ASN_EINVAL;
break;
case INTEGER:
case ENUMERATED:
if(is_int(&e, &v))
int_enc(&p, v, 0, lenonly);
else {
if(is_bigint(&e, &bb)) {
if(!lenonly)
memmove(p, bb->data, bb->len);
p += bb->len;
}
else
err = ASN_EINVAL;
}
break;
case BIT_STRING:
if(is_bitstring(&e, &bits)) {
if(bits->len == 0) {
if(!lenonly)
*p = 0;
p++;
}
else {
v = bits->unusedbits;
if(v < 0 || v > 7)
err = ASN_EINVAL;
else {
if(!lenonly) {
*p = v;
memmove(p+1, bits->data, bits->len);
}
p += 1 + bits->len;
}
}
}
else
err = ASN_EINVAL;
break;
case OCTET_STRING:
case ObjectDescriptor:
case EXTERNAL:
case REAL:
case EMBEDDED_PDV:
bb = nil;
switch(e.val.tag) {
case VOctets:
bb = e.val.u.octetsval;
break;
case VReal:
bb = e.val.u.realval;
break;
case VOther:
bb = e.val.u.otherval;
break;
}
if(bb != nil) {
if(!lenonly)
memmove(p, bb->data, bb->len);
p += bb->len;
}
else
err = ASN_EINVAL;
break;
case NULLTAG:
break;
case OBJECT_ID:
if(is_oid(&e, &oid)) {
for(k = 0; k < oid->len; k++) {
v = oid->data[k];
if(k == 0) {
v *= 40;
if(oid->len > 1)
v += oid->data[++k];
}
uint7_enc(&p, v, lenonly);
}
}
else
err = ASN_EINVAL;
break;
case SEQUENCE:
case SETOF:
el = nil;
if(e.val.tag == VSeq)
el = e.val.u.seqval;
else if(e.val.tag == VSet)
el = e.val.u.setval;
else
err = ASN_EINVAL;
if(el != nil) {
*pconstr = CONSTR_MASK;
for(; el != nil; el = el->tl) {
err = enc(&p, el->hd, lenonly);
if(err != ASN_OK)
break;
}
}
break;
case UTF8String:
case NumericString:
case PrintableString:
case TeletexString:
case VideotexString:
case IA5String:
case UTCTime:
case GeneralizedTime:
case GraphicString:
case VisibleString:
case GeneralString:
case UniversalString:
case BMPString:
if(e.val.tag == VString) {
s = e.val.u.stringval;
if(s != nil) {
v = strlen(s);
if(!lenonly)
memmove(p, s, v);
p += v;
}
}
else
err = ASN_EINVAL;
break;
default:
err = ASN_EINVAL;
}
*pp = p;
return err;
}
/*
* Encode num as unsigned 7 bit values with top bit 1 on all bytes
* except last, only putting in bytes if !lenonly.
*/
static void
uint7_enc(uchar** pp, int num, int lenonly)
{
int n;
int v;
int k;
uchar* p;
p = *pp;
n = 1;
v = num >> 7;
while(v > 0) {
v >>= 7;
n++;
}
if(lenonly)
p += n;
else {
for(k = (n - 1)*7; k > 0; k -= 7)
*p++= ((num >> k)|0x80);
*p++ = (num&0x7F);
}
*pp = p;
}
/*
* Encode num as unsigned or signed integer,
* only putting in bytes if !lenonly.
* Encoding is length followed by bytes to concatenate.
*/
static void
int_enc(uchar** pp, int num, int unsgned, int lenonly)
{
int v;
int n;
int prevv;
int k;
uchar* p;
p = *pp;
v = num;
if(v < 0)
v = -(v + 1);
n = 1;
prevv = v;
v >>= 8;
while(v > 0) {
prevv = v;
v >>= 8;
n++;
}
if(!unsgned && (prevv&0x80))
n++;
if(lenonly)
p += n;
else {
for(k = (n - 1)*8; k >= 0; k -= 8)
*p++ = (num >> k);
}
*pp = p;
}
static int
ints_eq(Ints* a, Ints* b)
{
int alen;
int i;
alen = a->len;
if(alen != b->len)
return 0;
for(i = 0; i < alen; i++)
if(a->data[i] != b->data[i])
return 0;
return 1;
}
/*
* Look up o in tab (which must have nil entry to terminate).
* Return index of matching entry, or -1 if none.
*/
static int
oid_lookup(Ints* o, Ints** tab)
{
int i;
for(i = 0; tab[i] != nil; i++)
if(ints_eq(o, tab[i]))
return i;
return -1;
}
/*
* Return true if *pe is a SEQUENCE, and set *pseq to
* the value of the sequence if so.
*/
static int
is_seq(Elem* pe, Elist** pseq)
{
if(pe->tag.class == Universal && pe->tag.num == SEQUENCE && pe->val.tag == VSeq) {
*pseq = pe->val.u.seqval;
return 1;
}
return 0;
}
static int
is_set(Elem* pe, Elist** pset)
{
if(pe->tag.class == Universal && pe->tag.num == SETOF && pe->val.tag == VSet) {
*pset = pe->val.u.setval;
return 1;
}
return 0;
}
static int
is_int(Elem* pe, int* pint)
{
if(pe->tag.class == Universal) {
if(pe->tag.num == INTEGER && pe->val.tag == VInt) {
*pint = pe->val.u.intval;
return 1;
}
else if(pe->tag.num == BOOLEAN && pe->val.tag == VBool) {
*pint = pe->val.u.boolval;
return 1;
}
}
return 0;
}
/*
* for convience, all VInt's are readable via this routine,
* as well as all VBigInt's
*/
static int
is_bigint(Elem* pe, Bytes** pbigint)
{
int v, n, i;
if(pe->tag.class == Universal && pe->tag.num == INTEGER) {
if(pe->val.tag == VBigInt)
*pbigint = pe->val.u.bigintval;
else if(pe->val.tag == VInt){
v = pe->val.u.intval;
for(n = 1; n < 4; n++)
if((1 << (8 * n)) > v)
break;
*pbigint = newbytes(n);
for(i = 0; i < n; i++)
(*pbigint)->data[i] = (v >> ((n - 1 - i) * 8));
}else
return 0;
return 1;
}
return 0;
}
static int
is_bitstring(Elem* pe, Bits** pbits)
{
if(pe->tag.class == Universal && pe->tag.num == BIT_STRING && pe->val.tag == VBitString) {
*pbits = pe->val.u.bitstringval;
return 1;
}
return 0;
}
static int
is_octetstring(Elem* pe, Bytes** poctets)
{
if(pe->tag.class == Universal && pe->tag.num == OCTET_STRING && pe->val.tag == VOctets) {
*poctets = pe->val.u.octetsval;
return 1;
}
return 0;
}
static int
is_oid(Elem* pe, Ints** poid)
{
if(pe->tag.class == Universal && pe->tag.num == OBJECT_ID && pe->val.tag == VObjId) {
*poid = pe->val.u.objidval;
return 1;
}
return 0;
}
static int
is_string(Elem* pe, char** pstring)
{
if(pe->tag.class == Universal) {
switch(pe->tag.num) {
case UTF8String:
case NumericString:
case PrintableString:
case TeletexString:
case VideotexString:
case IA5String:
case GraphicString:
case VisibleString:
case GeneralString:
case UniversalString:
case BMPString:
if(pe->val.tag == VString) {
*pstring = pe->val.u.stringval;
return 1;
}
}
}
return 0;
}
static int
is_time(Elem* pe, char** ptime)
{
if(pe->tag.class == Universal
&& (pe->tag.num == UTCTime || pe->tag.num == GeneralizedTime)
&& pe->val.tag == VString) {
*ptime = pe->val.u.stringval;
return 1;
}
return 0;
}
/*
* malloc and return a new Bytes structure capable of
* holding len bytes. (len >= 0)
*/
static Bytes*
newbytes(int len)
{
Bytes* ans;
if(len < 0)
abort();
ans = (Bytes*)emalloc(OFFSETOF(data[0], Bytes) + len);
ans->len = len;
return ans;
}
/*
* newbytes(len), with data initialized from buf
*/
static Bytes*
makebytes(uchar* buf, int len)
{
Bytes* ans;
ans = newbytes(len);
memmove(ans->data, buf, len);
return ans;
}
static void
freebytes(Bytes* b)
{
free(b);
}
/*
* Make a new Bytes, containing bytes of b1 followed by those of b2.
* Either b1 or b2 or both can be nil.
*/
static Bytes*
catbytes(Bytes* b1, Bytes* b2)
{
Bytes* ans;
int n;
if(b1 == nil) {
if(b2 == nil)
ans = newbytes(0);
else
ans = makebytes(b2->data, b2->len);
}
else if(b2 == nil) {
ans = makebytes(b1->data, b1->len);
}
else {
n = b1->len + b2->len;
ans = newbytes(n);
ans->len = n;
memmove(ans->data, b1->data, b1->len);
memmove(ans->data+b1->len, b2->data, b2->len);
}
return ans;
}
/* len is number of ints */
static Ints*
newints(int len)
{
Ints* ans;
if(len < 0 || len > ((uint)-1>>1)/sizeof(int))
abort();
ans = (Ints*)emalloc(OFFSETOF(data[0], Ints) + len*sizeof(int));
ans->len = len;
return ans;
}
static Ints*
makeints(int* buf, int len)
{
Ints* ans;
ans = newints(len);
memmove(ans->data, buf, len*sizeof(int));
return ans;
}
static void
freeints(Ints* b)
{
free(b);
}
/* len is number of bytes */
static Bits*
newbits(int len)
{
Bits* ans;
if(len < 0)
abort();
ans = (Bits*)emalloc(OFFSETOF(data[0], Bits) + len);
ans->len = len;
ans->unusedbits = 0;
return ans;
}
static Bits*
makebits(uchar* buf, int len, int unusedbits)
{
Bits* ans;
ans = newbits(len);
memmove(ans->data, buf, len);
ans->unusedbits = unusedbits;
return ans;
}
static void
freebits(Bits* b)
{
free(b);
}
static Elist*
mkel(Elem e, Elist* tail)
{
Elist* el;
el = (Elist*)emalloc(sizeof(Elist));
setmalloctag(el, getcallerpc(&e));
el->hd = e;
el->tl = tail;
return el;
}
static int
elistlen(Elist* el)
{
int ans = 0;
while(el != nil) {
ans++;
el = el->tl;
}
return ans;
}
/* Frees elist, but not fields inside values of constituent elems */
static void
freeelist(Elist* el)
{
Elist* next;
while(el != nil) {
next = el->tl;
free(el);
el = next;
}
}
/* free any allocated structures inside v (recursively freeing Elists) */
static void
freevalfields(Value* v)
{
Elist* el;
Elist* l;
if(v == nil)
return;
switch(v->tag) {
case VOctets:
freebytes(v->u.octetsval);
break;
case VBigInt:
freebytes(v->u.bigintval);
break;
case VReal:
freebytes(v->u.realval);
break;
case VOther:
freebytes(v->u.otherval);
break;
case VBitString:
freebits(v->u.bitstringval);
break;
case VObjId:
freeints(v->u.objidval);
break;
case VString:
if(v->u.stringval)
free(v->u.stringval);
break;
case VSeq:
el = v->u.seqval;
for(l = el; l != nil; l = l->tl)
freevalfields(&l->hd.val);
freeelist(el);
break;
case VSet:
el = v->u.setval;
for(l = el; l != nil; l = l->tl)
freevalfields(&l->hd.val);
freeelist(el);
break;
}
}
/* end of general ASN1 functions */
/*=============================================================*/
/*
* Decode and parse an X.509 Certificate, defined by this ASN1:
* Certificate ::= SEQUENCE {
* certificateInfo CertificateInfo,
* signatureAlgorithm AlgorithmIdentifier,
* signature BIT STRING }
*
* CertificateInfo ::= SEQUENCE {
* version [0] INTEGER DEFAULT v1 (0),
* serialNumber INTEGER,
* signature AlgorithmIdentifier,
* issuer Name,
* validity Validity,
* subject Name,
* subjectPublicKeyInfo SubjectPublicKeyInfo }
* (version v2 has two more fields, optional unique identifiers for
* issuer and subject; since we ignore these anyway, we won't parse them)
*
* Validity ::= SEQUENCE {
* notBefore UTCTime,
* notAfter UTCTime }
*
* SubjectPublicKeyInfo ::= SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING }
*
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFER,
* parameters ANY DEFINED BY ALGORITHM OPTIONAL }
*
* Name ::= SEQUENCE OF RelativeDistinguishedName
*
* RelativeDistinguishedName ::= SETOF SIZE(1..MAX) OF AttributeTypeAndValue
*
* AttributeTypeAndValue ::= SEQUENCE {
* type OBJECT IDENTIFER,
* value DirectoryString }
* (selected attributes have these Object Ids:
* commonName {2 5 4 3}
* countryName {2 5 4 6}
* localityName {2 5 4 7}
* stateOrProvinceName {2 5 4 8}
* organizationName {2 5 4 10}
* organizationalUnitName {2 5 4 11}
* )
*
* DirectoryString ::= CHOICE {
* teletexString TeletexString,
* printableString PrintableString,
* universalString UniversalString }
*
* See rfc1423, rfc2437 for AlgorithmIdentifier, subjectPublicKeyInfo, signature.
*
* Not yet implemented:
* CertificateRevocationList ::= SIGNED SEQUENCE{
* signature AlgorithmIdentifier,
* issuer Name,
* lastUpdate UTCTime,
* nextUpdate UTCTime,
* revokedCertificates
* SEQUENCE OF CRLEntry OPTIONAL}
* CRLEntry ::= SEQUENCE{
* userCertificate SerialNumber,
* revocationDate UTCTime}
*/
typedef struct CertX509 {
int serial;
char* issuer;
char* validity_start;
char* validity_end;
char* subject;
int publickey_alg;
Bytes* publickey;
int signature_alg;
Bytes* signature;
} CertX509;
/* Algorithm object-ids */
enum {
ALG_rsaEncryption,
ALG_md2WithRSAEncryption,
ALG_md4WithRSAEncryption,
ALG_md5WithRSAEncryption,
ALG_sha1WithRSAEncryption,
ALG_sha1WithRSAEncryptionOiw,
ALG_sha256WithRSAEncryption,
ALG_sha384WithRSAEncryption,
ALG_sha512WithRSAEncryption,
ALG_sha224WithRSAEncryption,
ALG_md5,
ALG_sha1,
ALG_sha256,
ALG_sha384,
ALG_sha512,
ALG_sha224,
NUMALGS
};
typedef struct Ints15 {
int len;
int data[15];
} Ints15;
typedef struct DigestAlg {
int alg;
DigestState* (*fun)(uchar*,ulong,uchar*,DigestState*);
int len;
} DigestAlg;
static DigestAlg alg_md5 = { ALG_md5, md5, MD5dlen};
static DigestAlg alg_sha1 = { ALG_sha1, sha1, SHA1dlen };
static DigestAlg alg_sha256 = { ALG_sha256, sha2_256, SHA2_256dlen };
static DigestAlg alg_sha384 = { ALG_sha384, sha2_384, SHA2_384dlen };
static DigestAlg alg_sha512 = { ALG_sha512, sha2_512, SHA2_512dlen };
static DigestAlg alg_sha224 = { ALG_sha224, sha2_224, SHA2_224dlen };
/* maximum length of digest output of the digest algs above */
enum {
MAXdlen = SHA2_512dlen,
};
static Ints15 oid_rsaEncryption = {7, 1, 2, 840, 113549, 1, 1, 1 };
static Ints15 oid_md2WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 2 };
static Ints15 oid_md4WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 3 };
static Ints15 oid_md5WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 4 };
static Ints15 oid_sha1WithRSAEncryption ={7, 1, 2, 840, 113549, 1, 1, 5 };
static Ints15 oid_sha1WithRSAEncryptionOiw ={6, 1, 3, 14, 3, 2, 29 };
static Ints15 oid_sha256WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 11 };
static Ints15 oid_sha384WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 12 };
static Ints15 oid_sha512WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 13 };
static Ints15 oid_sha224WithRSAEncryption = {7, 1, 2, 840, 113549, 1, 1, 14 };
static Ints15 oid_md5 = {6, 1, 2, 840, 113549, 2, 5 };
static Ints15 oid_sha1 = {6, 1, 3, 14, 3, 2, 26 };
static Ints15 oid_sha256= {9, 2, 16, 840, 1, 101, 3, 4, 2, 1 };
static Ints15 oid_sha384= {9, 2, 16, 840, 1, 101, 3, 4, 2, 2 };
static Ints15 oid_sha512= {9, 2, 16, 840, 1, 101, 3, 4, 2, 3 };
static Ints15 oid_sha224= {9, 2, 16, 840, 1, 101, 3, 4, 2, 4 };
static Ints *alg_oid_tab[NUMALGS+1] = {
(Ints*)&oid_rsaEncryption,
(Ints*)&oid_md2WithRSAEncryption,
(Ints*)&oid_md4WithRSAEncryption,
(Ints*)&oid_md5WithRSAEncryption,
(Ints*)&oid_sha1WithRSAEncryption,
(Ints*)&oid_sha1WithRSAEncryptionOiw,
(Ints*)&oid_sha256WithRSAEncryption,
(Ints*)&oid_sha384WithRSAEncryption,
(Ints*)&oid_sha512WithRSAEncryption,
(Ints*)&oid_sha224WithRSAEncryption,
(Ints*)&oid_md5,
(Ints*)&oid_sha1,
(Ints*)&oid_sha256,
(Ints*)&oid_sha384,
(Ints*)&oid_sha512,
(Ints*)&oid_sha224,
nil
};
static DigestAlg *digestalg[NUMALGS+1] = {
&alg_md5, &alg_md5, &alg_md5, &alg_md5,
&alg_sha1, &alg_sha1,
&alg_sha256, &alg_sha384, &alg_sha512, &alg_sha224,
&alg_md5, &alg_sha1, &alg_sha256, &alg_sha384, &alg_sha512, &alg_sha224,
nil
};
static void
freecert(CertX509* c)
{
if(c == nil)
return;
free(c->issuer);
free(c->validity_start);
free(c->validity_end);
free(c->subject);
freebytes(c->publickey);
freebytes(c->signature);
free(c);
}
/*
* Parse the Name ASN1 type.
* The sequence of RelativeDistinguishedName's gives a sort of pathname,
* from most general to most specific. Each element of the path can be
* one or more (but usually just one) attribute-value pair, such as
* countryName="US".
* We'll just form a "postal-style" address string by concatenating the elements
* from most specific to least specific, separated by commas.
* Return name-as-string (which must be freed by caller).
*/
static char*
parse_name(Elem* e)
{
Elist* el;
Elem* es;
Elist* esetl;
Elem* eat;
Elist* eatl;
char* s;
enum { MAXPARTS = 100 };
char* parts[MAXPARTS];
int i;
int plen;
char* ans = nil;
if(!is_seq(e, &el))
goto errret;
i = 0;
plen = 0;
while(el != nil) {
es = &el->hd;
if(!is_set(es, &esetl))
goto errret;
while(esetl != nil) {
eat = &esetl->hd;
if(!is_seq(eat, &eatl) || elistlen(eatl) != 2)
goto errret;
if(!is_string(&eatl->tl->hd, &s) || i>=MAXPARTS)
goto errret;
parts[i++] = s;
plen += strlen(s) + 2; /* room for ", " after */
esetl = esetl->tl;
}
el = el->tl;
}
if(i > 0) {
ans = (char*)emalloc(plen);
*ans = '\0';
while(--i >= 0) {
s = parts[i];
strcat(ans, s);
if(i > 0)
strcat(ans, ", ");
}
}
errret:
return ans;
}
/*
* Parse an AlgorithmIdentifer ASN1 type.
* Look up the oid in oid_tab and return one of OID_rsaEncryption, etc..,
* or -1 if not found.
* For now, ignore parameters, since none of our algorithms need them.
*/
static int
parse_alg(Elem* e)
{
Elist* el;
Ints* oid;
if(!is_seq(e, &el) || el == nil || !is_oid(&el->hd, &oid))
return -1;
return oid_lookup(oid, alg_oid_tab);
}
static CertX509*
decode_cert(Bytes* a)
{
int ok = 0;
int n;
CertX509* c = nil;
Elem ecert;
Elem* ecertinfo;
Elem* esigalg;
Elem* esig;
Elem* eserial;
Elem* eissuer;
Elem* evalidity;
Elem* esubj;
Elem* epubkey;
Elist* el;
Elist* elcert = nil;
Elist* elcertinfo = nil;
Elist* elvalidity = nil;
Elist* elpubkey = nil;
Bits* bits = nil;
Bytes* b;
Elem* e;
if(decode(a->data, a->len, &ecert) != ASN_OK)
goto errret;
c = (CertX509*)emalloc(sizeof(CertX509));
c->serial = -1;
c->issuer = nil;
c->validity_start = nil;
c->validity_end = nil;
c->subject = nil;
c->publickey_alg = -1;
c->publickey = nil;
c->signature_alg = -1;
c->signature = nil;
/* Certificate */
if(!is_seq(&ecert, &elcert) || elistlen(elcert) !=3)
goto errret;
ecertinfo = &elcert->hd;
el = elcert->tl;
esigalg = &el->hd;
c->signature_alg = parse_alg(esigalg);
el = el->tl;
esig = &el->hd;
/* Certificate Info */
if(!is_seq(ecertinfo, &elcertinfo))
goto errret;
n = elistlen(elcertinfo);
if(n < 6)
goto errret;
eserial =&elcertinfo->hd;
el = elcertinfo->tl;
/* check for optional version, marked by explicit context tag 0 */
if(eserial->tag.class == Context && eserial->tag.num == 0) {
eserial = &el->hd;
if(n < 7)
goto errret;
el = el->tl;
}
if(parse_alg(&el->hd) != c->signature_alg)
goto errret;
el = el->tl;
eissuer = &el->hd;
el = el->tl;
evalidity = &el->hd;
el = el->tl;
esubj = &el->hd;
el = el->tl;
epubkey = &el->hd;
if(!is_int(eserial, &c->serial)) {
if(!is_bigint(eserial, &b))
goto errret;
c->serial = -1; /* else we have to change cert struct */
}
c->issuer = parse_name(eissuer);
if(c->issuer == nil)
goto errret;
/* Validity */
if(!is_seq(evalidity, &elvalidity))
goto errret;
if(elistlen(elvalidity) != 2)
goto errret;
e = &elvalidity->hd;
if(!is_time(e, &c->validity_start))
goto errret;
e->val.u.stringval = nil; /* string ownership transfer */
e = &elvalidity->tl->hd;
if(!is_time(e, &c->validity_end))
goto errret;
e->val.u.stringval = nil; /* string ownership transfer */
/* resume CertificateInfo */
c->subject = parse_name(esubj);
if(c->subject == nil)
goto errret;
/* SubjectPublicKeyInfo */
if(!is_seq(epubkey, &elpubkey))
goto errret;
if(elistlen(elpubkey) != 2)
goto errret;
c->publickey_alg = parse_alg(&elpubkey->hd);
if(c->publickey_alg < 0)
goto errret;
if(!is_bitstring(&elpubkey->tl->hd, &bits))
goto errret;
if(bits->unusedbits != 0)
goto errret;
c->publickey = makebytes(bits->data, bits->len);
/*resume Certificate */
if(c->signature_alg < 0)
goto errret;
if(!is_bitstring(esig, &bits))
goto errret;
c->signature = makebytes(bits->data, bits->len);
ok = 1;
errret:
freevalfields(&ecert.val); /* recurses through lists, too */
if(!ok){
freecert(c);
c = nil;
}
return c;
}
/*
* RSAPublickKey :: SEQUENCE {
* modulus INTEGER,
* publicExponent INTEGER
* }
*/
static RSApub*
decode_rsapubkey(Bytes* a)
{
Elem e;
Elist *el, *l;
mpint *mp;
RSApub* key;
l = nil;
key = rsapuballoc();
if(decode(a->data, a->len, &e) != ASN_OK)
goto errret;
if(!is_seq(&e, &el) || elistlen(el) != 2)
goto errret;
l = el;
key->n = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->ek = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
freeelist(l);
return key;
errret:
freeelist(l);
rsapubfree(key);
return nil;
}
/*
* RSAPrivateKey ::= SEQUENCE {
* version Version,
* modulus INTEGER, -- n
* publicExponent INTEGER, -- e
* privateExponent INTEGER, -- d
* prime1 INTEGER, -- p
* prime2 INTEGER, -- q
* exponent1 INTEGER, -- d mod (p-1)
* exponent2 INTEGER, -- d mod (q-1)
* coefficient INTEGER -- (inverse of q) mod p }
*/
static RSApriv*
decode_rsaprivkey(Bytes* a)
{
int version;
Elem e;
Elist *el;
mpint *mp;
RSApriv* key;
key = rsaprivalloc();
if(decode(a->data, a->len, &e) != ASN_OK)
goto errret;
if(!is_seq(&e, &el) || elistlen(el) != 9)
goto errret;
if(!is_int(&el->hd, &version) || version != 0)
goto errret;
el = el->tl;
key->pub.n = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->pub.ek = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->dk = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->q = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->p = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->kq = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->kp = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->c2 = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
return key;
errret:
rsaprivfree(key);
return nil;
}
/*
* DSAPrivateKey ::= SEQUENCE{
* version Version,
* p INTEGER,
* q INTEGER,
* g INTEGER, -- alpha
* pub_key INTEGER, -- key
* priv_key INTEGER, -- secret
* }
*/
static DSApriv*
decode_dsaprivkey(Bytes* a)
{
int version;
Elem e;
Elist *el;
mpint *mp;
DSApriv* key;
key = dsaprivalloc();
if(decode(a->data, a->len, &e) != ASN_OK)
goto errret;
if(!is_seq(&e, &el) || elistlen(el) != 6)
goto errret;
version = -1;
if(!is_int(&el->hd, &version) || version != 0)
{
fprint(2, "version %d\n", version);
goto errret;
}
el = el->tl;
key->pub.p = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->pub.q = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->pub.alpha = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->pub.key = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
el = el->tl;
key->secret = mp = asn1mpint(&el->hd);
if(mp == nil)
goto errret;
return key;
errret:
dsaprivfree(key);
return nil;
}
static mpint*
asn1mpint(Elem *e)
{
Bytes *b;
mpint *mp;
int v;
if(is_int(e, &v))
return itomp(v, nil);
if(is_bigint(e, &b)) {
mp = betomp(b->data, b->len, nil);
freebytes(b);
return mp;
}
return nil;
}
mpint*
pkcs1padbuf(uchar *buf, int len, mpint *modulus)
{
int n = (mpsignif(modulus)+7)/8;
int pm1, i;
uchar *p;
mpint *mp;
pm1 = n - 1 - len;
p = (uchar*)emalloc(n);
p[0] = 0;
p[1] = 1;
for(i = 2; i < pm1; i++)
p[i] = 0xFF;
p[pm1] = 0;
memcpy(&p[pm1+1], buf, len);
mp = betomp(p, n, nil);
free(p);
return mp;
}
static mpint*
pkcs1pad(Bytes *b, mpint *modulus)
{
return pkcs1padbuf(b->data, b->len, modulus);
}
RSApriv*
asn1toRSApriv(uchar *kd, int kn)
{
Bytes *b;
RSApriv *key;
b = makebytes(kd, kn);
key = decode_rsaprivkey(b);
freebytes(b);
return key;
}
DSApriv*
asn1toDSApriv(uchar *kd, int kn)
{
Bytes *b;
DSApriv *key;
b = makebytes(kd, kn);
key = decode_dsaprivkey(b);
freebytes(b);
return key;
}
/*
* digest(CertificateInfo)
* Our ASN.1 library doesn't return pointers into the original
* data array, so we need to do a little hand decoding.
*/
static int
digest_certinfo(Bytes *cert, DigestAlg *da, uchar *digest)
{
uchar *info, *p, *pend;
ulong infolen;
int isconstr, length;
Tag tag;
Elem elem;
p = cert->data;
pend = cert->data + cert->len;
if(tag_decode(&p, pend, &tag, &isconstr) != ASN_OK ||
tag.class != Universal || tag.num != SEQUENCE ||
length_decode(&p, pend, &length) != ASN_OK ||
p+length > pend ||
p+length < p)
return -1;
info = p;
if(ber_decode(&p, pend, &elem) != ASN_OK)
return -1;
freevalfields(&elem.val);
if(elem.tag.num != SEQUENCE)
return -1;
infolen = p - info;
(*da->fun)(info, infolen, digest, nil);
return da->len;
}
static char*
verify_signature(Bytes* signature, RSApub *pk, uchar *edigest, int edigestlen, Elem **psigalg)
{
Elem e;
Elist *el;
Bytes *digest;
uchar *pkcs1buf, *buf;
int buflen;
mpint *pkcs1;
int nlen;
char *err;
err = nil;
pkcs1buf = nil;
/* one less than the byte length of the modulus */
nlen = (mpsignif(pk->n)-1)/8;
/* see 9.2.1 of rfc2437 */
pkcs1 = betomp(signature->data, signature->len, nil);
mpexp(pkcs1, pk->ek, pk->n, pkcs1);
buflen = mptobe(pkcs1, nil, 0, &pkcs1buf);
buf = pkcs1buf;
if(buflen != nlen || buf[0] != 1) {
err = "expected 1";
goto end;
}
buf++, buflen--;
while(buflen > 0 && buf[0] == 0xff)
buf++, buflen--;
if(buflen < 1 || buf[0] != 0) {
err = "expected 0";
goto end;
}
buf++, buflen--;
if(decode(buf, buflen, &e) != ASN_OK || !is_seq(&e, &el) || elistlen(el) != 2 ||
!is_octetstring(&el->tl->hd, &digest)) {
err = "signature parse error";
goto end;
}
*psigalg = &el->hd;
if(digest->len != edigestlen) {
err = "bad digest length";
goto end;
}
if(memcmp(digest->data, edigest, edigestlen) != 0)
err = "digests did not match";
end:
mpfree(pkcs1);
free(pkcs1buf);
return err;
}
RSApub*
X509toRSApub(uchar *cert, int ncert, char *name, int nname)
{
char *e;
Bytes *b;
CertX509 *c;
RSApub *pk;
b = makebytes(cert, ncert);
c = decode_cert(b);
freebytes(b);
if(c == nil)
return nil;
if(name != nil && c->subject != nil){
e = strchr(c->subject, ',');
if(e != nil)
*e = 0; /* take just CN part of Distinguished Name */
strncpy(name, c->subject, nname);
}
pk = decode_rsapubkey(c->publickey);
freecert(c);
return pk;
}
char*
X509verify(uchar *cert, int ncert, RSApub *pk)
{
char *e;
Bytes *b;
CertX509 *c;
int digestlen;
uchar digest[MAXdlen];
Elem *sigalg;
b = makebytes(cert, ncert);
c = decode_cert(b);
if(c == nil){
freebytes(b);
return "cannot decode cert";
}
digestlen = digest_certinfo(b, digestalg[c->signature_alg], digest);
freebytes(b);
if(digestlen <= 0){
freecert(c);
return "cannot decode certinfo";
}
e = verify_signature(c->signature, pk, digest, digestlen, &sigalg);
freecert(c);
return e;
}
/* ------- Elem constructors ---------- */
static Elem
Null(void)
{
Elem e;
e.tag.class = Universal;
e.tag.num = NULLTAG;
e.val.tag = VNull;
return e;
}
static Elem
mkint(int j)
{
Elem e;
e.tag.class = Universal;
e.tag.num = INTEGER;
e.val.tag = VInt;
e.val.u.intval = j;
return e;
}
static Elem
mkbigint(mpint *p)
{
Elem e;
uchar *buf;
int buflen;
e.tag.class = Universal;
e.tag.num = INTEGER;
e.val.tag = VBigInt;
buflen = mptobe(p, nil, 0, &buf);
e.val.u.bigintval = makebytes(buf, buflen);
free(buf);
return e;
}
static Elem
mkstring(char *s)
{
Elem e;
e.tag.class = Universal;
e.tag.num = IA5String;
e.val.tag = VString;
e.val.u.stringval = estrdup(s);
return e;
}
static Elem
mkoctet(uchar *buf, int buflen)
{
Elem e;
e.tag.class = Universal;
e.tag.num = OCTET_STRING;
e.val.tag = VOctets;
e.val.u.octetsval = makebytes(buf, buflen);
return e;
}
static Elem
mkbits(uchar *buf, int buflen)
{
Elem e;
e.tag.class = Universal;
e.tag.num = BIT_STRING;
e.val.tag = VBitString;
e.val.u.bitstringval = makebits(buf, buflen, 0);
return e;
}
static Elem
mkutc(long t)
{
Elem e;
char utc[50];
Tm *tm = gmtime(t);
e.tag.class = Universal;
e.tag.num = UTCTime;
e.val.tag = VString;
snprint(utc, sizeof(utc), "%.2d%.2d%.2d%.2d%.2d%.2dZ",
tm->year % 100, tm->mon+1, tm->mday, tm->hour, tm->min, tm->sec);
e.val.u.stringval = estrdup(utc);
return e;
}
static Elem
mkoid(Ints *oid)
{
Elem e;
e.tag.class = Universal;
e.tag.num = OBJECT_ID;
e.val.tag = VObjId;
e.val.u.objidval = makeints(oid->data, oid->len);
return e;
}
static Elem
mkseq(Elist *el)
{
Elem e;
e.tag.class = Universal;
e.tag.num = SEQUENCE;
e.val.tag = VSeq;
e.val.u.seqval = el;
return e;
}
static Elem
mkset(Elist *el)
{
Elem e;
e.tag.class = Universal;
e.tag.num = SETOF;
e.val.tag = VSet;
e.val.u.setval = el;
return e;
}
static Elem
mkalg(int alg)
{
return mkseq(mkel(mkoid(alg_oid_tab[alg]), mkel(Null(), nil)));
}
typedef struct Ints7pref {
int len;
int data[7];
char prefix[4];
} Ints7pref;
Ints7pref DN_oid[] = {
{4, 2, 5, 4, 6, 0, 0, 0, "C="},
{4, 2, 5, 4, 8, 0, 0, 0, "ST="},
{4, 2, 5, 4, 7, 0, 0, 0, "L="},
{4, 2, 5, 4, 10, 0, 0, 0, "O="},
{4, 2, 5, 4, 11, 0, 0, 0, "OU="},
{4, 2, 5, 4, 3, 0, 0, 0, "CN="},
{7, 1,2,840,113549,1,9,1, "E="},
};
static Elem
mkname(Ints7pref *oid, char *subj)
{
return mkset(mkel(mkseq(mkel(mkoid((Ints*)oid), mkel(mkstring(subj), nil))), nil));
}
static Elem
mkDN(char *dn)
{
int i, j, nf;
char *f[20], *prefix, *d2 = estrdup(dn);
Elist* el = nil;
nf = tokenize(d2, f, nelem(f));
for(i=nf-1; i>=0; i--){
for(j=0; j<nelem(DN_oid); j++){
prefix = DN_oid[j].prefix;
if(strncmp(f[i],prefix,strlen(prefix))==0){
el = mkel(mkname(&DN_oid[j],f[i]+strlen(prefix)), el);
break;
}
}
}
free(d2);
return mkseq(el);
}
uchar*
X509gen(RSApriv *priv, char *subj, ulong valid[2], int *certlen)
{
int serial = 0, sigalg = ALG_sha256WithRSAEncryption;
uchar *cert = nil;
RSApub *pk = rsaprivtopub(priv);
Bytes *certbytes, *pkbytes, *certinfobytes, *sigbytes;
Elem e, certinfo, issuer, subject, pubkey, validity, sig;
DigestAlg *da;
uchar digest[MAXdlen], *buf;
int buflen;
mpint *pkcs1;
e.val.tag = VInt; /* so freevalfields at errret is no-op */
issuer = mkDN(subj);
subject = mkDN(subj);
pubkey = mkseq(mkel(mkbigint(pk->n),mkel(mkint(mptoi(pk->ek)),nil)));
if(encode(pubkey, &pkbytes) != ASN_OK)
goto errret;
freevalfields(&pubkey.val);
pubkey = mkseq(
mkel(mkalg(ALG_rsaEncryption),
mkel(mkbits(pkbytes->data, pkbytes->len),
nil)));
freebytes(pkbytes);
validity = mkseq(
mkel(mkutc(valid[0]),
mkel(mkutc(valid[1]),
nil)));
certinfo = mkseq(
mkel(mkint(serial),
mkel(mkalg(sigalg),
mkel(issuer,
mkel(validity,
mkel(subject,
mkel(pubkey,
nil)))))));
if(encode(certinfo, &certinfobytes) != ASN_OK)
goto errret;
da = digestalg[sigalg];
(*da->fun)(certinfobytes->data, certinfobytes->len, digest, 0);
freebytes(certinfobytes);
sig = mkseq(
mkel(mkalg(da->alg),
mkel(mkoctet(digest, da->len),
nil)));
if(encode(sig, &sigbytes) != ASN_OK)
goto errret;
pkcs1 = pkcs1pad(sigbytes, pk->n);
freebytes(sigbytes);
rsadecrypt(priv, pkcs1, pkcs1);
buflen = mptobe(pkcs1, nil, 0, &buf);
mpfree(pkcs1);
e = mkseq(
mkel(certinfo,
mkel(mkalg(sigalg),
mkel(mkbits(buf, buflen),
nil))));
free(buf);
if(encode(e, &certbytes) != ASN_OK)
goto errret;
if(certlen)
*certlen = certbytes->len;
cert = certbytes->data;
errret:
freevalfields(&e.val);
return cert;
}
uchar*
X509req(RSApriv *priv, char *subj, int *certlen)
{
/* RFC 2314, PKCS #10 Certification Request Syntax */
int version = 0, sigalg = ALG_sha256WithRSAEncryption;
uchar *cert = nil;
RSApub *pk = rsaprivtopub(priv);
Bytes *certbytes, *pkbytes, *certinfobytes, *sigbytes;
Elem e, certinfo, subject, pubkey, sig;
DigestAlg *da;
uchar digest[MAXdlen], *buf;
int buflen;
mpint *pkcs1;
e.val.tag = VInt; /* so freevalfields at errret is no-op */
subject = mkDN(subj);
pubkey = mkseq(mkel(mkbigint(pk->n),mkel(mkint(mptoi(pk->ek)),nil)));
if(encode(pubkey, &pkbytes) != ASN_OK)
goto errret;
freevalfields(&pubkey.val);
pubkey = mkseq(
mkel(mkalg(ALG_rsaEncryption),
mkel(mkbits(pkbytes->data, pkbytes->len),
nil)));
freebytes(pkbytes);
certinfo = mkseq(
mkel(mkint(version),
mkel(subject,
mkel(pubkey,
nil))));
if(encode(certinfo, &certinfobytes) != ASN_OK)
goto errret;
da = digestalg[sigalg];
(*da->fun)(certinfobytes->data, certinfobytes->len, digest, 0);
freebytes(certinfobytes);
sig = mkseq(
mkel(mkalg(da->alg),
mkel(mkoctet(digest, da->len),
nil)));
if(encode(sig, &sigbytes) != ASN_OK)
goto errret;
pkcs1 = pkcs1pad(sigbytes, pk->n);
freebytes(sigbytes);
rsadecrypt(priv, pkcs1, pkcs1);
buflen = mptobe(pkcs1, nil, 0, &buf);
mpfree(pkcs1);
e = mkseq(
mkel(certinfo,
mkel(mkalg(sigalg),
mkel(mkbits(buf, buflen),
nil))));
free(buf);
if(encode(e, &certbytes) != ASN_OK)
goto errret;
if(certlen)
*certlen = certbytes->len;
cert = certbytes->data;
errret:
freevalfields(&e.val);
return cert;
}
static char*
tagdump(Tag tag)
{
if(tag.class != Universal)
return smprint("class%d,num%d", tag.class, tag.num);
switch(tag.num){
case BOOLEAN: return "BOOLEAN";
case INTEGER: return "INTEGER";
case BIT_STRING: return "BIT STRING";
case OCTET_STRING: return "OCTET STRING";
case NULLTAG: return "NULLTAG";
case OBJECT_ID: return "OID";
case ObjectDescriptor: return "OBJECT_DES";
case EXTERNAL: return "EXTERNAL";
case REAL: return "REAL";
case ENUMERATED: return "ENUMERATED";
case EMBEDDED_PDV: return "EMBEDDED PDV";
case SEQUENCE: return "SEQUENCE";
case SETOF: return "SETOF";
case UTF8String: return "UTF8String";
case NumericString: return "NumericString";
case PrintableString: return "PrintableString";
case TeletexString: return "TeletexString";
case VideotexString: return "VideotexString";
case IA5String: return "IA5String";
case UTCTime: return "UTCTime";
case GeneralizedTime: return "GeneralizedTime";
case GraphicString: return "GraphicString";
case VisibleString: return "VisibleString";
case GeneralString: return "GeneralString";
case UniversalString: return "UniversalString";
case BMPString: return "BMPString";
default:
return smprint("Universal,num%d", tag.num);
}
}
static void
edump(Elem e)
{
Value v;
Elist *el;
int i;
print("%s{", tagdump(e.tag));
v = e.val;
switch(v.tag){
case VBool: print("Bool %d",v.u.boolval); break;
case VInt: print("Int %d",v.u.intval); break;
case VOctets: print("Octets[%d] %.2x%.2x...",v.u.octetsval->len,v.u.octetsval->data[0],v.u.octetsval->data[1]); break;
case VBigInt: print("BigInt[%d] %.2x%.2x...",v.u.bigintval->len,v.u.bigintval->data[0],v.u.bigintval->data[1]); break;
case VReal: print("Real..."); break;
case VOther: print("Other..."); break;
case VBitString: print("BitString..."); break;
case VNull: print("Null"); break;
case VEOC: print("EOC..."); break;
case VObjId: print("ObjId");
for(i = 0; i<v.u.objidval->len; i++)
print(" %d", v.u.objidval->data[i]);
break;
case VString: print("String \"%s\"",v.u.stringval); break;
case VSeq: print("Seq\n");
for(el = v.u.seqval; el!=nil; el = el->tl)
edump(el->hd);
break;
case VSet: print("Set\n");
for(el = v.u.setval; el!=nil; el = el->tl)
edump(el->hd);
break;
}
print("}\n");
}
void
asn1dump(uchar *der, int len)
{
Elem e;
if(decode(der, len, &e) != ASN_OK){
print("didn't parse\n");
exits("didn't parse");
}
edump(e);
}
void
X509dump(uchar *cert, int ncert)
{
char *e;
Bytes *b;
CertX509 *c;
RSApub *pk;
int digestlen;
uchar digest[MAXdlen];
Elem *sigalg;
print("begin X509dump\n");
b = makebytes(cert, ncert);
c = decode_cert(b);
if(c == nil){
freebytes(b);
print("cannot decode cert\n");
return;
}
digestlen = digest_certinfo(b, digestalg[c->signature_alg], digest);
freebytes(b);
if(digestlen <= 0){
freecert(c);
print("cannot decode certinfo\n");
return;
}
print("serial %d\n", c->serial);
print("issuer %s\n", c->issuer);
print("validity %s %s\n", c->validity_start, c->validity_end);
print("subject %s\n", c->subject);
pk = decode_rsapubkey(c->publickey);
print("pubkey e=%B n(%d)=%B\n", pk->ek, mpsignif(pk->n), pk->n);
print("sigalg=%d digest=%.*H\n", c->signature_alg, digestlen, digest);
e = verify_signature(c->signature, pk, digest, digestlen, &sigalg);
if(e==nil){
e = "nil (meaning ok)";
print("sigalg=\n");
if(sigalg)
edump(*sigalg);
}
print("self-signed verify_signature returns: %s\n", e);
rsapubfree(pk);
freecert(c);
print("end X509dump\n");
}