ref: c78edf544d755f68094101224be16fdc5ab5e788
dir: /libsec/tlshand.c/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <mp.h>
#include <libsec.h>
// The main groups of functions are:
// client/server - main handshake protocol definition
// message functions - formating handshake messages
// cipher choices - catalog of digest and encrypt algorithms
// security functions - PKCS#1, sslHMAC, session keygen
// general utility functions - malloc, serialization
// The handshake protocol builds on the TLS/SSL3 record layer protocol,
// which is implemented in kernel device #a. See also /lib/rfc/rfc2246.
enum {
TLSFinishedLen = 12,
SSL3FinishedLen = MD5dlen+SHA1dlen,
MaxKeyData = 160, // amount of secret we may need
MAXdlen = SHA2_512dlen,
RandomSize = 32,
MasterSecretSize = 48,
AQueue = 0,
AFlush = 1,
};
typedef struct Bytes{
int len;
uchar data[];
} Bytes;
typedef struct Ints{
int len;
int data[];
} Ints;
typedef struct Algs{
char *enc;
char *digest;
int nsecret;
int tlsid;
int ok;
} Algs;
typedef struct Namedcurve{
int tlsid;
void (*init)(mpint *p, mpint *a, mpint *b, mpint *x, mpint *y, mpint *n, mpint *h);
} Namedcurve;
typedef struct Finished{
uchar verify[SSL3FinishedLen];
int n;
} Finished;
typedef struct HandshakeHash {
MD5state md5;
SHAstate sha1;
SHA2_256state sha2_256;
} HandshakeHash;
typedef struct TlsSec TlsSec;
struct TlsSec {
RSApub *rsapub;
AuthRpc *rpc; // factotum for rsa private key
uchar *psk; // pre-shared key
int psklen;
int clientVers; // version in ClientHello
uchar sec[MasterSecretSize]; // master secret
uchar srandom[RandomSize]; // server random
uchar crandom[RandomSize]; // client random
Namedcurve *nc; // selected curve for ECDHE
// diffie hellman state
DHstate dh;
struct {
ECdomain dom;
ECpriv Q;
} ec;
uchar X[32];
// byte generation and handshake checksum
void (*prf)(uchar*, int, uchar*, int, char*, uchar*, int);
void (*setFinished)(TlsSec*, HandshakeHash, uchar*, int);
int nfin;
};
typedef struct TlsConnection{
TlsSec sec[1]; // security management goo
int hand, ctl; // record layer file descriptors
int erred; // set when tlsError called
int (*trace)(char*fmt, ...); // for debugging
int version; // protocol we are speaking
Bytes *cert; // server certificate; only last - no chain
int cipher;
int nsecret; // amount of secret data to init keys
char *digest; // name of digest algorithm to use
char *enc; // name of encryption algorithm to use
// for finished messages
HandshakeHash handhash;
Finished finished;
uchar *sendp;
uchar buf[1<<16];
} TlsConnection;
typedef struct Msg{
int tag;
union {
struct {
int version;
uchar random[RandomSize];
Bytes* sid;
Ints* ciphers;
Bytes* compressors;
Bytes* extensions;
} clientHello;
struct {
int version;
uchar random[RandomSize];
Bytes* sid;
int cipher;
int compressor;
Bytes* extensions;
} serverHello;
struct {
int ncert;
Bytes **certs;
} certificate;
struct {
Bytes *types;
Ints *sigalgs;
int nca;
Bytes **cas;
} certificateRequest;
struct {
Bytes *pskid;
Bytes *key;
} clientKeyExchange;
struct {
Bytes *pskid;
Bytes *dh_p;
Bytes *dh_g;
Bytes *dh_Ys;
Bytes *dh_parameters;
Bytes *dh_signature;
int sigalg;
int curve;
} serverKeyExchange;
struct {
int sigalg;
Bytes *signature;
} certificateVerify;
Finished finished;
} u;
} Msg;
enum {
SSL3Version = 0x0300,
TLS10Version = 0x0301,
TLS11Version = 0x0302,
TLS12Version = 0x0303,
ProtocolVersion = TLS12Version, // maximum version we speak
MinProtoVersion = 0x0300, // limits on version we accept
MaxProtoVersion = 0x03ff,
};
// handshake type
enum {
HHelloRequest,
HClientHello,
HServerHello,
HSSL2ClientHello = 9, /* local convention; see devtls.c */
HCertificate = 11,
HServerKeyExchange,
HCertificateRequest,
HServerHelloDone,
HCertificateVerify,
HClientKeyExchange,
HFinished = 20,
HMax
};
// alerts
enum {
ECloseNotify = 0,
EUnexpectedMessage = 10,
EBadRecordMac = 20,
EDecryptionFailed = 21,
ERecordOverflow = 22,
EDecompressionFailure = 30,
EHandshakeFailure = 40,
ENoCertificate = 41,
EBadCertificate = 42,
EUnsupportedCertificate = 43,
ECertificateRevoked = 44,
ECertificateExpired = 45,
ECertificateUnknown = 46,
EIllegalParameter = 47,
EUnknownCa = 48,
EAccessDenied = 49,
EDecodeError = 50,
EDecryptError = 51,
EExportRestriction = 60,
EProtocolVersion = 70,
EInsufficientSecurity = 71,
EInternalError = 80,
EInappropriateFallback = 86,
EUserCanceled = 90,
ENoRenegotiation = 100,
EUnknownPSKidentity = 115,
EMax = 256
};
// cipher suites
enum {
TLS_RSA_WITH_3DES_EDE_CBC_SHA = 0X000A,
TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA = 0X0016,
TLS_RSA_WITH_AES_128_CBC_SHA = 0X002F,
TLS_DHE_RSA_WITH_AES_128_CBC_SHA = 0X0033,
TLS_RSA_WITH_AES_256_CBC_SHA = 0X0035,
TLS_DHE_RSA_WITH_AES_256_CBC_SHA = 0X0039,
TLS_RSA_WITH_AES_128_CBC_SHA256 = 0X003C,
TLS_RSA_WITH_AES_256_CBC_SHA256 = 0X003D,
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 = 0X0067,
TLS_RSA_WITH_AES_128_GCM_SHA256 = 0x009C,
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 = 0x009E,
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA = 0xC013,
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA = 0xC014,
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 = 0xC023,
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 = 0xC027,
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 = 0xC02B,
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 = 0xC02F,
GOOGLE_ECDHE_RSA_WITH_CHACHA20_POLY1305 = 0xCC13,
GOOGLE_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 = 0xCC14,
GOOGLE_DHE_RSA_WITH_CHACHA20_POLY1305 = 0xCC15,
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 = 0xCCA8,
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 = 0xCCA9,
TLS_DHE_RSA_WITH_CHACHA20_POLY1305 = 0xCCAA,
TLS_PSK_WITH_CHACHA20_POLY1305 = 0xCCAB,
TLS_PSK_WITH_AES_128_CBC_SHA256 = 0x00AE,
TLS_PSK_WITH_AES_128_CBC_SHA = 0x008C,
TLS_FALLBACK_SCSV = 0x5600,
};
// compression methods
enum {
CompressionNull = 0,
CompressionMax
};
// curves
enum {
X25519 = 0x001d,
};
// extensions
enum {
Extsni = 0x0000,
Extec = 0x000a,
Extecp = 0x000b,
Extsigalgs = 0x000d,
};
static Algs cipherAlgs[] = {
// ECDHE-ECDSA
{"ccpoly96_aead", "clear", 2*(32+12), TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305},
{"ccpoly64_aead", "clear", 2*32, GOOGLE_ECDHE_ECDSA_WITH_CHACHA20_POLY1305},
{"aes_128_gcm_aead", "clear", 2*(16+4), TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256},
// ECDHE-RSA
{"ccpoly96_aead", "clear", 2*(32+12), TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305},
{"ccpoly64_aead", "clear", 2*32, GOOGLE_ECDHE_RSA_WITH_CHACHA20_POLY1305},
{"aes_128_gcm_aead", "clear", 2*(16+4), TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256},
{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256},
{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA},
{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA},
// DHE-RSA
{"ccpoly96_aead", "clear", 2*(32+12), TLS_DHE_RSA_WITH_CHACHA20_POLY1305},
{"ccpoly64_aead", "clear", 2*32, GOOGLE_DHE_RSA_WITH_CHACHA20_POLY1305},
{"aes_128_gcm_aead", "clear", 2*(16+4), TLS_DHE_RSA_WITH_AES_128_GCM_SHA256},
{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_DHE_RSA_WITH_AES_128_CBC_SHA256},
{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_DHE_RSA_WITH_AES_128_CBC_SHA},
{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_DHE_RSA_WITH_AES_256_CBC_SHA},
{"3des_ede_cbc","sha1", 2*(4*8+SHA1dlen), TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA},
// RSA
{"aes_128_gcm_aead", "clear", 2*(16+4), TLS_RSA_WITH_AES_128_GCM_SHA256},
{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_RSA_WITH_AES_128_CBC_SHA256},
{"aes_256_cbc", "sha256", 2*(32+16+SHA2_256dlen), TLS_RSA_WITH_AES_256_CBC_SHA256},
{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_RSA_WITH_AES_128_CBC_SHA},
{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_RSA_WITH_AES_256_CBC_SHA},
{"3des_ede_cbc","sha1", 2*(4*8+SHA1dlen), TLS_RSA_WITH_3DES_EDE_CBC_SHA},
// PSK
{"ccpoly96_aead", "clear", 2*(32+12), TLS_PSK_WITH_CHACHA20_POLY1305},
{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_PSK_WITH_AES_128_CBC_SHA256},
{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_PSK_WITH_AES_128_CBC_SHA},
};
static uchar compressors[] = {
CompressionNull,
};
static Namedcurve namedcurves[] = {
X25519, nil,
0x0017, secp256r1,
0x0018, secp384r1,
};
static uchar pointformats[] = {
CompressionNull /* support of uncompressed point format is mandatory */
};
static struct {
DigestState* (*fun)(uchar*, ulong, uchar*, DigestState*);
int len;
} hashfun[] = {
/* [0x00] is reserved for MD5+SHA1 for < TLS1.2 */
[0x01] {md5, MD5dlen},
[0x02] {sha1, SHA1dlen},
[0x03] {sha2_224, SHA2_224dlen},
[0x04] {sha2_256, SHA2_256dlen},
[0x05] {sha2_384, SHA2_384dlen},
[0x06] {sha2_512, SHA2_512dlen},
};
// signature algorithms (only RSA and ECDSA at the moment)
static int sigalgs[] = {
0x0603, /* SHA512 ECDSA */
0x0503, /* SHA384 ECDSA */
0x0403, /* SHA256 ECDSA */
0x0203, /* SHA1 ECDSA */
0x0601, /* SHA512 RSA */
0x0501, /* SHA384 RSA */
0x0401, /* SHA256 RSA */
0x0201, /* SHA1 RSA */
};
static TlsConnection *tlsServer2(int ctl, int hand,
uchar *cert, int certlen,
char *pskid, uchar *psk, int psklen,
int (*trace)(char*fmt, ...), PEMChain *chain);
static TlsConnection *tlsClient2(int ctl, int hand,
uchar *cert, int certlen,
char *pskid, uchar *psk, int psklen,
uchar *ext, int extlen, int (*trace)(char*fmt, ...));
static void msgClear(Msg *m);
static char* msgPrint(char *buf, int n, Msg *m);
static int msgRecv(TlsConnection *c, Msg *m);
static int msgSend(TlsConnection *c, Msg *m, int act);
static void tlsError(TlsConnection *c, int err, char *msg, ...);
static int setVersion(TlsConnection *c, int version);
static int setSecrets(TlsConnection *c, int isclient);
static int finishedMatch(TlsConnection *c, Finished *f);
static void tlsConnectionFree(TlsConnection *c);
static int isDHE(int tlsid);
static int isECDHE(int tlsid);
static int isPSK(int tlsid);
static int isECDSA(int tlsid);
static int setAlgs(TlsConnection *c, int a);
static int okCipher(Ints *cv, int ispsk, int canec);
static int okCompression(Bytes *cv);
static int initCiphers(void);
static Ints* makeciphers(int ispsk);
static AuthRpc* factotum_rsa_open(RSApub *rsapub);
static mpint* factotum_rsa_decrypt(AuthRpc *rpc, mpint *cipher);
static void factotum_rsa_close(AuthRpc *rpc);
static void tlsSecInits(TlsSec *sec, int cvers, uchar *crandom);
static int tlsSecRSAs(TlsSec *sec, Bytes *epm);
static Bytes* tlsSecECDHEs1(TlsSec *sec);
static int tlsSecECDHEs2(TlsSec *sec, Bytes *Yc);
static void tlsSecInitc(TlsSec *sec, int cvers);
static Bytes* tlsSecRSAc(TlsSec *sec, uchar *cert, int ncert);
static Bytes* tlsSecDHEc(TlsSec *sec, Bytes *p, Bytes *g, Bytes *Ys);
static Bytes* tlsSecECDHEc(TlsSec *sec, int curve, Bytes *Ys);
static void tlsSecVers(TlsSec *sec, int v);
static int tlsSecFinished(TlsSec *sec, HandshakeHash hsh, uchar *fin, int nfin, int isclient);
static void setMasterSecret(TlsSec *sec, Bytes *pm);
static int digestDHparams(TlsSec *sec, Bytes *par, uchar digest[MAXdlen], int sigalg);
static char* verifyDHparams(TlsSec *sec, Bytes *par, Bytes *cert, Bytes *sig, int sigalg);
static Bytes* pkcs1_encrypt(Bytes* data, RSApub* key);
static Bytes* pkcs1_decrypt(TlsSec *sec, Bytes *data);
static Bytes* pkcs1_sign(TlsSec *sec, uchar *digest, int digestlen, int sigalg);
static void* emalloc(int);
static void* erealloc(void*, int);
static void put32(uchar *p, u32int);
static void put24(uchar *p, int);
static void put16(uchar *p, int);
static int get24(uchar *p);
static int get16(uchar *p);
static Bytes* newbytes(int len);
static Bytes* makebytes(uchar* buf, int len);
static Bytes* mptobytes(mpint* big, int len);
static mpint* bytestomp(Bytes* bytes);
static void freebytes(Bytes* b);
static Ints* newints(int len);
static void freeints(Ints* b);
static int lookupid(Ints* b, int id);
/* x509.c */
extern mpint* pkcs1padbuf(uchar *buf, int len, mpint *modulus, int blocktype);
extern int pkcs1unpadbuf(uchar *buf, int len, mpint *modulus, int blocktype);
extern int asn1encodedigest(DigestState* (*fun)(uchar*, ulong, uchar*, DigestState*), uchar *digest, uchar *buf, int len);
//================= client/server ========================
// push TLS onto fd, returning new (application) file descriptor
// or -1 if error.
int
tlsServer(int fd, TLSconn *conn)
{
char buf[8];
char dname[64];
uchar seed[2*RandomSize];
int n, data, ctl, hand;
TlsConnection *tls;
if(conn == nil)
return -1;
ctl = open("#a/tls/clone", ORDWR|OCEXEC);
if(ctl < 0)
return -1;
n = read(ctl, buf, sizeof(buf)-1);
if(n < 0){
close(ctl);
return -1;
}
buf[n] = 0;
snprint(conn->dir, sizeof(conn->dir), "#a/tls/%s", buf);
snprint(dname, sizeof(dname), "#a/tls/%s/hand", buf);
hand = open(dname, ORDWR|OCEXEC);
if(hand < 0){
close(ctl);
return -1;
}
data = -1;
fprint(ctl, "fd %d 0x%x", fd, ProtocolVersion);
tls = tlsServer2(ctl, hand,
conn->cert, conn->certlen,
conn->pskID, conn->psk, conn->psklen,
conn->trace, conn->chain);
if(tls != nil){
snprint(dname, sizeof(dname), "#a/tls/%s/data", buf);
data = open(dname, ORDWR);
}
close(hand);
close(ctl);
if(data < 0){
tlsConnectionFree(tls);
return -1;
}
free(conn->cert);
conn->cert = nil; // client certificates are not yet implemented
conn->certlen = 0;
conn->sessionIDlen = 0;
conn->sessionID = nil;
if(conn->sessionKey != nil
&& conn->sessionType != nil
&& strcmp(conn->sessionType, "ttls") == 0){
memmove(seed, tls->sec->crandom, RandomSize);
memmove(seed+RandomSize, tls->sec->srandom, RandomSize);
tls->sec->prf(
conn->sessionKey, conn->sessionKeylen,
tls->sec->sec, MasterSecretSize,
conn->sessionConst,
seed, sizeof(seed));
}
tlsConnectionFree(tls);
close(fd);
return data;
}
static uchar*
tlsClientExtensions(TLSconn *conn, int *plen)
{
uchar *b, *p;
int i, n, m;
p = b = nil;
// RFC6066 - Server Name Identification
if(conn->serverName != nil && (n = strlen(conn->serverName)) > 0){
m = p - b;
b = erealloc(b, m + 2+2+2+1+2+n);
p = b + m;
put16(p, Extsni), p += 2; /* Type: server_name */
put16(p, 2+1+2+n), p += 2; /* Length */
put16(p, 1+2+n), p += 2; /* Server Name list length */
*p++ = 0; /* Server Name Type: host_name */
put16(p, n), p += 2; /* Server Name length */
memmove(p, conn->serverName, n);
p += n;
}
// Elliptic Curves (also called Supported Groups)
if(ProtocolVersion >= TLS10Version){
m = p - b;
b = erealloc(b, m + 2+2+2+nelem(namedcurves)*2 + 2+2+1+nelem(pointformats));
p = b + m;
n = nelem(namedcurves);
put16(p, Extec), p += 2; /* Type: elliptic_curves / supported_groups */
put16(p, (n+1)*2), p += 2; /* Length */
put16(p, n*2), p += 2; /* Elliptic Curves Length */
for(i=0; i < n; i++){ /* Elliptic Curves */
put16(p, namedcurves[i].tlsid);
p += 2;
}
n = nelem(pointformats);
put16(p, Extecp), p += 2; /* Type: ec_point_formats */
put16(p, n+1), p += 2; /* Length */
*p++ = n; /* EC point formats Length */
for(i=0; i < n; i++) /* EC point formats */
*p++ = pointformats[i];
}
// signature algorithms
if(ProtocolVersion >= TLS12Version){
n = nelem(sigalgs);
m = p - b;
b = erealloc(b, m + 2+2+2+n*2);
p = b + m;
put16(p, Extsigalgs), p += 2;
put16(p, n*2 + 2), p += 2;
put16(p, n*2), p += 2;
for(i=0; i < n; i++){
put16(p, sigalgs[i]);
p += 2;
}
}
*plen = p - b;
return b;
}
// push TLS onto fd, returning new (application) file descriptor
// or -1 if error.
int
tlsClient(int fd, TLSconn *conn)
{
char buf[8];
char dname[64];
uchar seed[2*RandomSize];
int n, data, ctl, hand;
TlsConnection *tls;
uchar *ext;
if(conn == nil)
return -1;
ctl = open("#a/tls/clone", ORDWR|OCEXEC);
if(ctl < 0)
return -1;
n = read(ctl, buf, sizeof(buf)-1);
if(n < 0){
close(ctl);
return -1;
}
buf[n] = 0;
snprint(conn->dir, sizeof(conn->dir), "#a/tls/%s", buf);
snprint(dname, sizeof(dname), "#a/tls/%s/hand", buf);
hand = open(dname, ORDWR|OCEXEC);
if(hand < 0){
close(ctl);
return -1;
}
snprint(dname, sizeof(dname), "#a/tls/%s/data", buf);
data = open(dname, ORDWR);
if(data < 0){
close(hand);
close(ctl);
return -1;
}
fprint(ctl, "fd %d 0x%x", fd, ProtocolVersion);
ext = tlsClientExtensions(conn, &n);
tls = tlsClient2(ctl, hand,
conn->cert, conn->certlen,
conn->pskID, conn->psk, conn->psklen,
ext, n, conn->trace);
free(ext);
close(hand);
close(ctl);
if(tls == nil){
close(data);
return -1;
}
free(conn->cert);
if(tls->cert != nil){
conn->certlen = tls->cert->len;
conn->cert = emalloc(conn->certlen);
memcpy(conn->cert, tls->cert->data, conn->certlen);
} else {
conn->certlen = 0;
conn->cert = nil;
}
conn->sessionIDlen = 0;
conn->sessionID = nil;
if(conn->sessionKey != nil
&& conn->sessionType != nil
&& strcmp(conn->sessionType, "ttls") == 0){
memmove(seed, tls->sec->crandom, RandomSize);
memmove(seed+RandomSize, tls->sec->srandom, RandomSize);
tls->sec->prf(
conn->sessionKey, conn->sessionKeylen,
tls->sec->sec, MasterSecretSize,
conn->sessionConst,
seed, sizeof(seed));
}
tlsConnectionFree(tls);
close(fd);
return data;
}
static int
countchain(PEMChain *p)
{
int i = 0;
while (p) {
i++;
p = p->next;
}
return i;
}
static int
checkClientExtensions(TlsConnection *c, Bytes *ext)
{
uchar *p, *e;
int i, j, n;
if(ext == nil)
return 0;
for(p = ext->data, e = p+ext->len; p < e; p += n){
if(e-p < 4)
goto Short;
p += 4;
if(e-p < (n = get16(p-2)))
goto Short;
switch(get16(p-4)){
case Extec:
if(n < 4 || n % 2 || get16(p) != (n -= 2))
goto Short;
p += 2;
for(i = 0; i < nelem(namedcurves) && c->sec->nc == nil; i++)
for(j = 0; j < n; j += 2)
if(namedcurves[i].tlsid == get16(p+j)){
c->sec->nc = &namedcurves[i];
break;
}
break;
}
}
return 0;
Short:
tlsError(c, EDecodeError, "clienthello extensions has invalid length");
return -1;
}
static TlsConnection *
tlsServer2(int ctl, int hand,
uchar *cert, int certlen,
char *pskid, uchar *psk, int psklen,
int (*trace)(char*fmt, ...), PEMChain *chp)
{
int cipher, compressor, numcerts, i;
TlsConnection *c;
Msg m;
if(trace)
trace("tlsServer2\n");
if(!initCiphers())
return nil;
c = emalloc(sizeof(TlsConnection));
c->ctl = ctl;
c->hand = hand;
c->trace = trace;
c->version = ProtocolVersion;
c->sendp = c->buf;
memset(&m, 0, sizeof(m));
if(!msgRecv(c, &m)){
if(trace)
trace("initial msgRecv failed\n");
goto Err;
}
if(m.tag != HClientHello) {
tlsError(c, EUnexpectedMessage, "expected a client hello");
goto Err;
}
if(trace)
trace("ClientHello version %x\n", m.u.clientHello.version);
if(setVersion(c, m.u.clientHello.version) < 0) {
tlsError(c, EIllegalParameter, "incompatible version");
goto Err;
}
if(c->version < ProtocolVersion
&& lookupid(m.u.clientHello.ciphers, TLS_FALLBACK_SCSV) >= 0){
tlsError(c, EInappropriateFallback, "inappropriate fallback");
goto Err;
}
tlsSecInits(c->sec, m.u.clientHello.version, m.u.clientHello.random);
tlsSecVers(c->sec, c->version);
if(psklen > 0){
c->sec->psk = psk;
c->sec->psklen = psklen;
}
if(certlen > 0){
/* server certificate */
c->sec->rsapub = X509toRSApub(cert, certlen, nil, 0);
if(c->sec->rsapub == nil){
tlsError(c, EHandshakeFailure, "invalid X509/rsa certificate");
goto Err;
}
c->sec->rpc = factotum_rsa_open(c->sec->rsapub);
if(c->sec->rpc == nil){
tlsError(c, EHandshakeFailure, "factotum_rsa_open: %r");
goto Err;
}
}
if(checkClientExtensions(c, m.u.clientHello.extensions) < 0)
goto Err;
cipher = okCipher(m.u.clientHello.ciphers, psklen > 0, c->sec->nc != nil);
if(cipher < 0 || !setAlgs(c, cipher)) {
tlsError(c, EHandshakeFailure, "no matching cipher suite");
goto Err;
}
compressor = okCompression(m.u.clientHello.compressors);
if(compressor < 0) {
tlsError(c, EHandshakeFailure, "no matching compressor");
goto Err;
}
if(trace)
trace(" cipher %x, compressor %x\n", cipher, compressor);
msgClear(&m);
m.tag = HServerHello;
m.u.serverHello.version = c->version;
memmove(m.u.serverHello.random, c->sec->srandom, RandomSize);
m.u.serverHello.cipher = cipher;
m.u.serverHello.compressor = compressor;
m.u.serverHello.sid = makebytes(nil, 0);
if(!msgSend(c, &m, AQueue))
goto Err;
if(certlen > 0){
m.tag = HCertificate;
numcerts = countchain(chp);
m.u.certificate.ncert = 1 + numcerts;
m.u.certificate.certs = emalloc(m.u.certificate.ncert * sizeof(Bytes*));
m.u.certificate.certs[0] = makebytes(cert, certlen);
for (i = 0; i < numcerts && chp; i++, chp = chp->next)
m.u.certificate.certs[i+1] = makebytes(chp->pem, chp->pemlen);
if(!msgSend(c, &m, AQueue))
goto Err;
}
if(isECDHE(cipher)){
m.tag = HServerKeyExchange;
m.u.serverKeyExchange.curve = c->sec->nc->tlsid;
m.u.serverKeyExchange.dh_parameters = tlsSecECDHEs1(c->sec);
if(m.u.serverKeyExchange.dh_parameters == nil){
tlsError(c, EInternalError, "can't set DH parameters");
goto Err;
}
/* sign the DH parameters */
if(certlen > 0){
uchar digest[MAXdlen];
int digestlen;
if(c->version >= TLS12Version)
m.u.serverKeyExchange.sigalg = 0x0401; /* RSA SHA256 */
digestlen = digestDHparams(c->sec, m.u.serverKeyExchange.dh_parameters,
digest, m.u.serverKeyExchange.sigalg);
if((m.u.serverKeyExchange.dh_signature = pkcs1_sign(c->sec, digest, digestlen,
m.u.serverKeyExchange.sigalg)) == nil){
tlsError(c, EHandshakeFailure, "pkcs1_sign: %r");
goto Err;
}
}
if(!msgSend(c, &m, AQueue))
goto Err;
}
m.tag = HServerHelloDone;
if(!msgSend(c, &m, AFlush))
goto Err;
if(!msgRecv(c, &m))
goto Err;
if(m.tag != HClientKeyExchange) {
tlsError(c, EUnexpectedMessage, "expected a client key exchange");
goto Err;
}
if(pskid != nil){
if(m.u.clientKeyExchange.pskid == nil
|| m.u.clientKeyExchange.pskid->len != strlen(pskid)
|| memcmp(pskid, m.u.clientKeyExchange.pskid->data, m.u.clientKeyExchange.pskid->len) != 0){
tlsError(c, EUnknownPSKidentity, "unknown or missing pskid");
goto Err;
}
}
if(isECDHE(cipher)){
if(tlsSecECDHEs2(c->sec, m.u.clientKeyExchange.key) < 0){
tlsError(c, EHandshakeFailure, "couldn't set keys: %r");
goto Err;
}
} else if(certlen > 0){
if(tlsSecRSAs(c->sec, m.u.clientKeyExchange.key) < 0){
tlsError(c, EHandshakeFailure, "couldn't set keys: %r");
goto Err;
}
} else if(psklen > 0){
setMasterSecret(c->sec, newbytes(psklen));
} else {
tlsError(c, EInternalError, "no psk or certificate");
goto Err;
}
if(trace)
trace("tls secrets\n");
if(setSecrets(c, 0) < 0){
tlsError(c, EHandshakeFailure, "can't set secrets: %r");
goto Err;
}
/* no CertificateVerify; skip to Finished */
if(tlsSecFinished(c->sec, c->handhash, c->finished.verify, c->finished.n, 1) < 0){
tlsError(c, EInternalError, "can't set finished: %r");
goto Err;
}
if(!msgRecv(c, &m))
goto Err;
if(m.tag != HFinished) {
tlsError(c, EUnexpectedMessage, "expected a finished");
goto Err;
}
if(!finishedMatch(c, &m.u.finished)) {
tlsError(c, EHandshakeFailure, "finished verification failed");
goto Err;
}
msgClear(&m);
/* change cipher spec */
if(fprint(c->ctl, "changecipher") < 0){
tlsError(c, EInternalError, "can't enable cipher: %r");
goto Err;
}
if(tlsSecFinished(c->sec, c->handhash, c->finished.verify, c->finished.n, 0) < 0){
tlsError(c, EInternalError, "can't set finished: %r");
goto Err;
}
m.tag = HFinished;
m.u.finished = c->finished;
if(!msgSend(c, &m, AFlush))
goto Err;
if(trace)
trace("tls finished\n");
if(fprint(c->ctl, "opened") < 0)
goto Err;
return c;
Err:
msgClear(&m);
tlsConnectionFree(c);
return nil;
}
static Bytes*
tlsSecDHEc(TlsSec *sec, Bytes *p, Bytes *g, Bytes *Ys)
{
DHstate *dh = &sec->dh;
mpint *G, *P, *Y, *K;
Bytes *Yc;
int n;
if(p == nil || g == nil || Ys == nil)
return nil;
// reject dh primes that is susceptible to logjam
if(p->len <= 1024/8)
return nil;
Yc = nil;
P = bytestomp(p);
G = bytestomp(g);
Y = bytestomp(Ys);
K = nil;
if(dh_new(dh, P, nil, G) == nil)
goto Out;
n = (mpsignif(P)+7)/8;
Yc = mptobytes(dh->y, n);
K = dh_finish(dh, Y); /* zeros dh */
if(K == nil){
freebytes(Yc);
Yc = nil;
goto Out;
}
setMasterSecret(sec, mptobytes(K, n));
Out:
mpfree(K);
mpfree(Y);
mpfree(G);
mpfree(P);
return Yc;
}
static Bytes*
tlsSecECDHEc(TlsSec *sec, int curve, Bytes *Ys)
{
ECdomain *dom = &sec->ec.dom;
ECpriv *Q = &sec->ec.Q;
ECpub *pub;
ECpoint K;
Namedcurve *nc;
Bytes *Yc;
Bytes *Z;
int n;
if(Ys == nil)
return nil;
if(curve == X25519){
if(Ys->len != 32)
return nil;
Yc = newbytes(32);
curve25519_dh_new(sec->X, Yc->data);
Z = newbytes(32);
if(!curve25519_dh_finish(sec->X, Ys->data, Z->data)){
freebytes(Yc);
freebytes(Z);
return nil;
}
setMasterSecret(sec, Z);
}else{
for(nc = namedcurves; nc->tlsid != curve; nc++)
if(nc == &namedcurves[nelem(namedcurves)])
return nil;
ecdominit(dom, nc->init);
pub = ecdecodepub(dom, Ys->data, Ys->len);
if(pub == nil)
return nil;
memset(Q, 0, sizeof(*Q));
Q->a.x = mpnew(0);
Q->a.y = mpnew(0);
Q->d = mpnew(0);
memset(&K, 0, sizeof(K));
K.x = mpnew(0);
K.y = mpnew(0);
ecgen(dom, Q);
ecmul(dom, pub, Q->d, &K);
n = (mpsignif(dom->p)+7)/8;
setMasterSecret(sec, mptobytes(K.x, n));
Yc = newbytes(1 + 2*n);
Yc->len = ecencodepub(dom, &Q->a, Yc->data, Yc->len);
mpfree(K.x);
mpfree(K.y);
ecpubfree(pub);
}
return Yc;
}
static TlsConnection *
tlsClient2(int ctl, int hand,
uchar *cert, int certlen,
char *pskid, uchar *psk, int psklen,
uchar *ext, int extlen,
int (*trace)(char*fmt, ...))
{
int creq, dhx, cipher;
TlsConnection *c;
Bytes *epm;
Msg m;
if(!initCiphers())
return nil;
epm = nil;
memset(&m, 0, sizeof(m));
c = emalloc(sizeof(TlsConnection));
c->ctl = ctl;
c->hand = hand;
c->trace = trace;
c->cert = nil;
c->sendp = c->buf;
c->version = ProtocolVersion;
tlsSecInitc(c->sec, c->version);
if(psklen > 0){
c->sec->psk = psk;
c->sec->psklen = psklen;
}
if(certlen > 0){
/* client certificate */
c->sec->rsapub = X509toRSApub(cert, certlen, nil, 0);
if(c->sec->rsapub == nil){
tlsError(c, EInternalError, "invalid X509/rsa certificate");
goto Err;
}
c->sec->rpc = factotum_rsa_open(c->sec->rsapub);
if(c->sec->rpc == nil){
tlsError(c, EInternalError, "factotum_rsa_open: %r");
goto Err;
}
}
/* client hello */
m.tag = HClientHello;
m.u.clientHello.version = c->version;
memmove(m.u.clientHello.random, c->sec->crandom, RandomSize);
m.u.clientHello.sid = makebytes(nil, 0);
m.u.clientHello.ciphers = makeciphers(psklen > 0);
m.u.clientHello.compressors = makebytes(compressors,sizeof(compressors));
m.u.clientHello.extensions = makebytes(ext, extlen);
if(!msgSend(c, &m, AFlush))
goto Err;
/* server hello */
if(!msgRecv(c, &m))
goto Err;
if(m.tag != HServerHello) {
tlsError(c, EUnexpectedMessage, "expected a server hello");
goto Err;
}
if(setVersion(c, m.u.serverHello.version) < 0) {
tlsError(c, EIllegalParameter, "incompatible version: %r");
goto Err;
}
tlsSecVers(c->sec, c->version);
memmove(c->sec->srandom, m.u.serverHello.random, RandomSize);
cipher = m.u.serverHello.cipher;
if((psklen > 0) != isPSK(cipher) || !setAlgs(c, cipher)) {
tlsError(c, EIllegalParameter, "invalid cipher suite");
goto Err;
}
if(m.u.serverHello.compressor != CompressionNull) {
tlsError(c, EIllegalParameter, "invalid compression");
goto Err;
}
dhx = isDHE(cipher) || isECDHE(cipher);
if(!msgRecv(c, &m))
goto Err;
if(m.tag == HCertificate){
if(m.u.certificate.ncert < 1) {
tlsError(c, EIllegalParameter, "runt certificate");
goto Err;
}
c->cert = makebytes(m.u.certificate.certs[0]->data, m.u.certificate.certs[0]->len);
if(!msgRecv(c, &m))
goto Err;
} else if(psklen == 0) {
tlsError(c, EUnexpectedMessage, "expected a certificate");
goto Err;
}
if(m.tag == HServerKeyExchange) {
if(dhx){
char *err = verifyDHparams(c->sec,
m.u.serverKeyExchange.dh_parameters,
c->cert,
m.u.serverKeyExchange.dh_signature,
c->version<TLS12Version ? 0x01 : m.u.serverKeyExchange.sigalg);
if(err != nil){
tlsError(c, EBadCertificate, "can't verify DH parameters: %s", err);
goto Err;
}
if(isECDHE(cipher))
epm = tlsSecECDHEc(c->sec,
m.u.serverKeyExchange.curve,
m.u.serverKeyExchange.dh_Ys);
else
epm = tlsSecDHEc(c->sec,
m.u.serverKeyExchange.dh_p,
m.u.serverKeyExchange.dh_g,
m.u.serverKeyExchange.dh_Ys);
if(epm == nil){
tlsError(c, EHandshakeFailure, "bad DH parameters");
goto Err;
}
} else if(psklen == 0){
tlsError(c, EUnexpectedMessage, "got an server key exchange");
goto Err;
}
if(!msgRecv(c, &m))
goto Err;
} else if(dhx){
tlsError(c, EUnexpectedMessage, "expected server key exchange");
goto Err;
}
/* certificate request (optional) */
creq = 0;
if(m.tag == HCertificateRequest) {
creq = 1;
if(!msgRecv(c, &m))
goto Err;
}
if(m.tag != HServerHelloDone) {
tlsError(c, EUnexpectedMessage, "expected a server hello done");
goto Err;
}
msgClear(&m);
if(!dhx){
if(c->cert != nil){
epm = tlsSecRSAc(c->sec, c->cert->data, c->cert->len);
if(epm == nil){
tlsError(c, EBadCertificate, "bad certificate: %r");
goto Err;
}
} else if(psklen > 0){
setMasterSecret(c->sec, newbytes(psklen));
} else {
tlsError(c, EInternalError, "no psk or certificate");
goto Err;
}
}
if(trace)
trace("tls secrets\n");
if(setSecrets(c, 1) < 0){
tlsError(c, EHandshakeFailure, "can't set secrets: %r");
goto Err;
}
if(creq) {
m.tag = HCertificate;
if(certlen > 0){
m.u.certificate.ncert = 1;
m.u.certificate.certs = emalloc(m.u.certificate.ncert * sizeof(Bytes*));
m.u.certificate.certs[0] = makebytes(cert, certlen);
}
if(!msgSend(c, &m, AFlush))
goto Err;
}
/* client key exchange */
m.tag = HClientKeyExchange;
if(psklen > 0){
if(pskid == nil)
pskid = "";
m.u.clientKeyExchange.pskid = makebytes((uchar*)pskid, strlen(pskid));
}
m.u.clientKeyExchange.key = epm;
epm = nil;
if(!msgSend(c, &m, AFlush))
goto Err;
/* certificate verify */
if(creq && certlen > 0) {
HandshakeHash hsave;
uchar digest[MAXdlen];
int digestlen;
/* save the state for the Finish message */
hsave = c->handhash;
if(c->version < TLS12Version){
md5(nil, 0, digest, &c->handhash.md5);
sha1(nil, 0, digest+MD5dlen, &c->handhash.sha1);
digestlen = MD5dlen+SHA1dlen;
} else {
m.u.certificateVerify.sigalg = 0x0401; /* RSA SHA256 */
sha2_256(nil, 0, digest, &c->handhash.sha2_256);
digestlen = SHA2_256dlen;
}
c->handhash = hsave;
if((m.u.certificateVerify.signature = pkcs1_sign(c->sec, digest, digestlen,
m.u.certificateVerify.sigalg)) == nil){
tlsError(c, EHandshakeFailure, "pkcs1_sign: %r");
goto Err;
}
m.tag = HCertificateVerify;
if(!msgSend(c, &m, AFlush))
goto Err;
}
/* change cipher spec */
if(fprint(c->ctl, "changecipher") < 0){
tlsError(c, EInternalError, "can't enable cipher: %r");
goto Err;
}
// Cipherchange must occur immediately before Finished to avoid
// potential hole; see section 4.3 of Wagner Schneier 1996.
if(tlsSecFinished(c->sec, c->handhash, c->finished.verify, c->finished.n, 1) < 0){
tlsError(c, EInternalError, "can't set finished 1: %r");
goto Err;
}
m.tag = HFinished;
m.u.finished = c->finished;
if(!msgSend(c, &m, AFlush)) {
tlsError(c, EInternalError, "can't flush after client Finished: %r");
goto Err;
}
if(tlsSecFinished(c->sec, c->handhash, c->finished.verify, c->finished.n, 0) < 0){
tlsError(c, EInternalError, "can't set finished 0: %r");
goto Err;
}
if(!msgRecv(c, &m)) {
tlsError(c, EInternalError, "can't read server Finished: %r");
goto Err;
}
if(m.tag != HFinished) {
tlsError(c, EUnexpectedMessage, "expected a Finished msg from server");
goto Err;
}
if(!finishedMatch(c, &m.u.finished)) {
tlsError(c, EHandshakeFailure, "finished verification failed");
goto Err;
}
msgClear(&m);
if(fprint(c->ctl, "opened") < 0){
if(trace)
trace("unable to do final open: %r\n");
goto Err;
}
return c;
Err:
free(epm);
msgClear(&m);
tlsConnectionFree(c);
return nil;
}
//================= message functions ========================
static void
msgHash(TlsConnection *c, uchar *p, int n)
{
md5(p, n, 0, &c->handhash.md5);
sha1(p, n, 0, &c->handhash.sha1);
if(c->version >= TLS12Version)
sha2_256(p, n, 0, &c->handhash.sha2_256);
}
static int
msgSend(TlsConnection *c, Msg *m, int act)
{
uchar *p, *e; // sendp = start of new message; p = write pointer; e = end pointer
int n, i;
p = c->sendp;
e = &c->buf[sizeof(c->buf)];
if(c->trace)
c->trace("send %s", msgPrint((char*)p, e - p, m));
p[0] = m->tag; // header - fill in size later
p += 4;
switch(m->tag) {
default:
tlsError(c, EInternalError, "can't encode a %d", m->tag);
goto Err;
case HClientHello:
if(p+2+RandomSize > e)
goto Overflow;
put16(p, m->u.clientHello.version), p += 2;
memmove(p, m->u.clientHello.random, RandomSize);
p += RandomSize;
if(p+1+(n = m->u.clientHello.sid->len) > e)
goto Overflow;
*p++ = n;
memmove(p, m->u.clientHello.sid->data, n);
p += n;
if(p+2+(n = m->u.clientHello.ciphers->len) > e)
goto Overflow;
put16(p, n*2), p += 2;
for(i=0; i<n; i++)
put16(p, m->u.clientHello.ciphers->data[i]), p += 2;
if(p+1+(n = m->u.clientHello.compressors->len) > e)
goto Overflow;
*p++ = n;
memmove(p, m->u.clientHello.compressors->data, n);
p += n;
if(m->u.clientHello.extensions == nil
|| (n = m->u.clientHello.extensions->len) == 0)
break;
if(p+2+n > e)
goto Overflow;
put16(p, n), p += 2;
memmove(p, m->u.clientHello.extensions->data, n);
p += n;
break;
case HServerHello:
if(p+2+RandomSize > e)
goto Overflow;
put16(p, m->u.serverHello.version), p += 2;
memmove(p, m->u.serverHello.random, RandomSize);
p += RandomSize;
if(p+1+(n = m->u.serverHello.sid->len) > e)
goto Overflow;
*p++ = n;
memmove(p, m->u.serverHello.sid->data, n);
p += n;
if(p+2+1 > e)
goto Overflow;
put16(p, m->u.serverHello.cipher), p += 2;
*p++ = m->u.serverHello.compressor;
if(m->u.serverHello.extensions == nil
|| (n = m->u.serverHello.extensions->len) == 0)
break;
if(p+2+n > e)
goto Overflow;
put16(p, n), p += 2;
memmove(p, m->u.serverHello.extensions->data, n);
p += n;
break;
case HServerHelloDone:
break;
case HCertificate:
n = 0;
for(i = 0; i < m->u.certificate.ncert; i++)
n += 3 + m->u.certificate.certs[i]->len;
if(p+3+n > e)
goto Overflow;
put24(p, n), p += 3;
for(i = 0; i < m->u.certificate.ncert; i++){
n = m->u.certificate.certs[i]->len;
put24(p, n), p += 3;
memmove(p, m->u.certificate.certs[i]->data, n);
p += n;
}
break;
case HCertificateVerify:
if(p+2+2+(n = m->u.certificateVerify.signature->len) > e)
goto Overflow;
if(m->u.certificateVerify.sigalg != 0)
put16(p, m->u.certificateVerify.sigalg), p += 2;
put16(p, n), p += 2;
memmove(p, m->u.certificateVerify.signature->data, n);
p += n;
break;
case HServerKeyExchange:
if(m->u.serverKeyExchange.pskid != nil){
if(p+2+(n = m->u.serverKeyExchange.pskid->len) > e)
goto Overflow;
put16(p, n), p += 2;
memmove(p, m->u.serverKeyExchange.pskid->data, n);
p += n;
}
if(m->u.serverKeyExchange.dh_parameters == nil)
break;
if(p+(n = m->u.serverKeyExchange.dh_parameters->len) > e)
goto Overflow;
memmove(p, m->u.serverKeyExchange.dh_parameters->data, n);
p += n;
if(m->u.serverKeyExchange.dh_signature == nil)
break;
if(p+2+2+(n = m->u.serverKeyExchange.dh_signature->len) > e)
goto Overflow;
if(c->version >= TLS12Version)
put16(p, m->u.serverKeyExchange.sigalg), p += 2;
put16(p, n), p += 2;
memmove(p, m->u.serverKeyExchange.dh_signature->data, n);
p += n;
break;
case HClientKeyExchange:
if(m->u.clientKeyExchange.pskid != nil){
if(p+2+(n = m->u.clientKeyExchange.pskid->len) > e)
goto Overflow;
put16(p, n), p += 2;
memmove(p, m->u.clientKeyExchange.pskid->data, n);
p += n;
}
if(m->u.clientKeyExchange.key == nil)
break;
if(p+2+(n = m->u.clientKeyExchange.key->len) > e)
goto Overflow;
if(isECDHE(c->cipher))
*p++ = n;
else if(isDHE(c->cipher) || c->version != SSL3Version)
put16(p, n), p += 2;
memmove(p, m->u.clientKeyExchange.key->data, n);
p += n;
break;
case HFinished:
if(p+m->u.finished.n > e)
goto Overflow;
memmove(p, m->u.finished.verify, m->u.finished.n);
p += m->u.finished.n;
break;
}
// go back and fill in size
n = p - c->sendp;
put24(c->sendp+1, n-4);
// remember hash of Handshake messages
if(m->tag != HHelloRequest)
msgHash(c, c->sendp, n);
c->sendp = p;
if(act == AFlush){
c->sendp = c->buf;
if(write(c->hand, c->buf, p - c->buf) < 0){
fprint(2, "write error: %r\n");
goto Err;
}
}
msgClear(m);
return 1;
Overflow:
tlsError(c, EInternalError, "not enougth send buffer for message (%d)", m->tag);
Err:
msgClear(m);
return 0;
}
static uchar*
tlsReadN(TlsConnection *c, int n)
{
uchar *p, *w, *e;
e = &c->buf[sizeof(c->buf)];
p = e - n;
if(n > sizeof(c->buf) || p < c->sendp){
tlsError(c, EDecodeError, "handshake message too long %d", n);
return nil;
}
for(w = p; w < e; w += n)
if((n = read(c->hand, w, e - w)) <= 0)
return nil;
return p;
}
static int
msgRecv(TlsConnection *c, Msg *m)
{
uchar *p, *s;
int type, n, nn, i;
msgClear(m);
for(;;) {
p = tlsReadN(c, 4);
if(p == nil)
return 0;
type = p[0];
n = get24(p+1);
if(type != HHelloRequest)
break;
if(n != 0) {
tlsError(c, EDecodeError, "invalid hello request during handshake");
return 0;
}
}
if(type == HSSL2ClientHello){
/* Cope with an SSL3 ClientHello expressed in SSL2 record format.
This is sent by some clients that we must interoperate
with, such as Java's JSSE and Microsoft's Internet Explorer. */
int nsid, nrandom, nciph;
p = tlsReadN(c, n);
if(p == nil)
return 0;
msgHash(c, p, n);
m->tag = HClientHello;
if(n < 22)
goto Short;
m->u.clientHello.version = get16(p+1);
p += 3;
n -= 3;
nn = get16(p); /* cipher_spec_len */
nsid = get16(p + 2);
nrandom = get16(p + 4);
p += 6;
n -= 6;
if(nsid != 0 /* no sid's, since shouldn't restart using ssl2 header */
|| nrandom < 16 || nn % 3 || n - nrandom < nn)
goto Err;
/* ignore ssl2 ciphers and look for {0x00, ssl3 cipher} */
nciph = 0;
for(i = 0; i < nn; i += 3)
if(p[i] == 0)
nciph++;
m->u.clientHello.ciphers = newints(nciph);
nciph = 0;
for(i = 0; i < nn; i += 3)
if(p[i] == 0)
m->u.clientHello.ciphers->data[nciph++] = get16(&p[i + 1]);
p += nn;
m->u.clientHello.sid = makebytes(nil, 0);
if(nrandom > RandomSize)
nrandom = RandomSize;
memset(m->u.clientHello.random, 0, RandomSize - nrandom);
memmove(&m->u.clientHello.random[RandomSize - nrandom], p, nrandom);
m->u.clientHello.compressors = newbytes(1);
m->u.clientHello.compressors->data[0] = CompressionNull;
goto Ok;
}
msgHash(c, p, 4);
p = tlsReadN(c, n);
if(p == nil)
return 0;
msgHash(c, p, n);
m->tag = type;
switch(type) {
default:
tlsError(c, EUnexpectedMessage, "can't decode a %d", type);
goto Err;
case HClientHello:
if(n < 2)
goto Short;
m->u.clientHello.version = get16(p);
p += 2, n -= 2;
if(n < RandomSize)
goto Short;
memmove(m->u.clientHello.random, p, RandomSize);
p += RandomSize, n -= RandomSize;
if(n < 1 || n < p[0]+1)
goto Short;
m->u.clientHello.sid = makebytes(p+1, p[0]);
p += m->u.clientHello.sid->len+1;
n -= m->u.clientHello.sid->len+1;
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn % 2 || n < nn || nn < 2)
goto Short;
m->u.clientHello.ciphers = newints(nn >> 1);
for(i = 0; i < nn; i += 2)
m->u.clientHello.ciphers->data[i >> 1] = get16(&p[i]);
p += nn, n -= nn;
if(n < 1 || n < p[0]+1 || p[0] == 0)
goto Short;
nn = p[0];
m->u.clientHello.compressors = makebytes(p+1, nn);
p += nn + 1, n -= nn + 1;
if(n < 2)
break;
nn = get16(p);
if(nn > n-2)
goto Short;
m->u.clientHello.extensions = makebytes(p+2, nn);
n -= nn + 2;
break;
case HServerHello:
if(n < 2)
goto Short;
m->u.serverHello.version = get16(p);
p += 2, n -= 2;
if(n < RandomSize)
goto Short;
memmove(m->u.serverHello.random, p, RandomSize);
p += RandomSize, n -= RandomSize;
if(n < 1 || n < p[0]+1)
goto Short;
m->u.serverHello.sid = makebytes(p+1, p[0]);
p += m->u.serverHello.sid->len+1;
n -= m->u.serverHello.sid->len+1;
if(n < 3)
goto Short;
m->u.serverHello.cipher = get16(p);
m->u.serverHello.compressor = p[2];
p += 3, n -= 3;
if(n < 2)
break;
nn = get16(p);
if(nn > n-2)
goto Short;
m->u.serverHello.extensions = makebytes(p+2, nn);
n -= nn + 2;
break;
case HCertificate:
if(n < 3)
goto Short;
nn = get24(p);
p += 3, n -= 3;
if(nn == 0 && n > 0)
goto Short;
/* certs */
i = 0;
while(n > 0) {
if(n < 3)
goto Short;
nn = get24(p);
p += 3, n -= 3;
if(nn > n)
goto Short;
m->u.certificate.ncert = i+1;
m->u.certificate.certs = erealloc(m->u.certificate.certs, (i+1)*sizeof(Bytes*));
m->u.certificate.certs[i] = makebytes(p, nn);
p += nn, n -= nn;
i++;
}
break;
case HCertificateRequest:
if(n < 1)
goto Short;
nn = p[0];
p++, n--;
if(nn > n)
goto Short;
m->u.certificateRequest.types = makebytes(p, nn);
p += nn, n -= nn;
if(c->version >= TLS12Version){
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn % 2)
goto Short;
m->u.certificateRequest.sigalgs = newints(nn>>1);
for(i = 0; i < nn; i += 2)
m->u.certificateRequest.sigalgs->data[i >> 1] = get16(&p[i]);
p += nn, n -= nn;
}
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
/* nn == 0 can happen; yahoo's servers do it */
if(nn != n)
goto Short;
/* cas */
i = 0;
while(n > 0) {
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn < 1 || nn > n)
goto Short;
m->u.certificateRequest.nca = i+1;
m->u.certificateRequest.cas = erealloc(
m->u.certificateRequest.cas, (i+1)*sizeof(Bytes*));
m->u.certificateRequest.cas[i] = makebytes(p, nn);
p += nn, n -= nn;
i++;
}
break;
case HServerHelloDone:
break;
case HServerKeyExchange:
if(isPSK(c->cipher)){
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn > n)
goto Short;
m->u.serverKeyExchange.pskid = makebytes(p, nn);
p += nn, n -= nn;
if(n == 0)
break;
}
if(n < 2)
goto Short;
s = p;
if(isECDHE(c->cipher)){
nn = *p;
p++, n--;
if(nn != 3 || nn > n) /* not a named curve */
goto Short;
nn = get16(p);
p += 2, n -= 2;
m->u.serverKeyExchange.curve = nn;
nn = *p++, n--;
if(nn < 1 || nn > n)
goto Short;
m->u.serverKeyExchange.dh_Ys = makebytes(p, nn);
p += nn, n -= nn;
}else if(isDHE(c->cipher)){
nn = get16(p);
p += 2, n -= 2;
if(nn < 1 || nn > n)
goto Short;
m->u.serverKeyExchange.dh_p = makebytes(p, nn);
p += nn, n -= nn;
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn < 1 || nn > n)
goto Short;
m->u.serverKeyExchange.dh_g = makebytes(p, nn);
p += nn, n -= nn;
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn < 1 || nn > n)
goto Short;
m->u.serverKeyExchange.dh_Ys = makebytes(p, nn);
p += nn, n -= nn;
} else {
/* should not happen */
goto Short;
}
m->u.serverKeyExchange.dh_parameters = makebytes(s, p - s);
if(n >= 2){
m->u.serverKeyExchange.sigalg = 0;
if(c->version >= TLS12Version){
m->u.serverKeyExchange.sigalg = get16(p);
p += 2, n -= 2;
if(n < 2)
goto Short;
}
nn = get16(p);
p += 2, n -= 2;
if(nn > 0 && nn <= n){
m->u.serverKeyExchange.dh_signature = makebytes(p, nn);
n -= nn;
}
}
break;
case HClientKeyExchange:
if(isPSK(c->cipher)){
if(n < 2)
goto Short;
nn = get16(p);
p += 2, n -= 2;
if(nn > n)
goto Short;
m->u.clientKeyExchange.pskid = makebytes(p, nn);
p += nn, n -= nn;
if(n == 0)
break;
}
if(n < 2)
goto Short;
if(isECDHE(c->cipher))
nn = *p++, n--;
else if(isDHE(c->cipher) || c->version != SSL3Version)
nn = get16(p), p += 2, n -= 2;
else
nn = n;
if(n < nn)
goto Short;
m->u.clientKeyExchange.key = makebytes(p, nn);
n -= nn;
break;
case HFinished:
m->u.finished.n = c->finished.n;
if(n < m->u.finished.n)
goto Short;
memmove(m->u.finished.verify, p, m->u.finished.n);
n -= m->u.finished.n;
break;
}
if(n != 0 && type != HClientHello && type != HServerHello)
goto Short;
Ok:
if(c->trace)
c->trace("recv %s", msgPrint((char*)c->sendp, &c->buf[sizeof(c->buf)] - c->sendp, m));
return 1;
Short:
tlsError(c, EDecodeError, "handshake message (%d) has invalid length", type);
Err:
msgClear(m);
return 0;
}
static void
msgClear(Msg *m)
{
int i;
switch(m->tag) {
case HHelloRequest:
break;
case HClientHello:
freebytes(m->u.clientHello.sid);
freeints(m->u.clientHello.ciphers);
freebytes(m->u.clientHello.compressors);
freebytes(m->u.clientHello.extensions);
break;
case HServerHello:
freebytes(m->u.serverHello.sid);
freebytes(m->u.serverHello.extensions);
break;
case HCertificate:
for(i=0; i<m->u.certificate.ncert; i++)
freebytes(m->u.certificate.certs[i]);
free(m->u.certificate.certs);
break;
case HCertificateRequest:
freebytes(m->u.certificateRequest.types);
freeints(m->u.certificateRequest.sigalgs);
for(i=0; i<m->u.certificateRequest.nca; i++)
freebytes(m->u.certificateRequest.cas[i]);
free(m->u.certificateRequest.cas);
break;
case HCertificateVerify:
freebytes(m->u.certificateVerify.signature);
break;
case HServerHelloDone:
break;
case HServerKeyExchange:
freebytes(m->u.serverKeyExchange.pskid);
freebytes(m->u.serverKeyExchange.dh_p);
freebytes(m->u.serverKeyExchange.dh_g);
freebytes(m->u.serverKeyExchange.dh_Ys);
freebytes(m->u.serverKeyExchange.dh_parameters);
freebytes(m->u.serverKeyExchange.dh_signature);
break;
case HClientKeyExchange:
freebytes(m->u.clientKeyExchange.pskid);
freebytes(m->u.clientKeyExchange.key);
break;
case HFinished:
break;
}
memset(m, 0, sizeof(Msg));
}
static char *
bytesPrint(char *bs, char *be, char *s0, Bytes *b, char *s1)
{
int i;
if(s0)
bs = seprint(bs, be, "%s", s0);
if(b == nil)
bs = seprint(bs, be, "nil");
else {
bs = seprint(bs, be, "<%d> [ ", b->len);
for(i=0; i<b->len; i++)
bs = seprint(bs, be, "%.2x ", b->data[i]);
bs = seprint(bs, be, "]");
}
if(s1)
bs = seprint(bs, be, "%s", s1);
return bs;
}
static char *
intsPrint(char *bs, char *be, char *s0, Ints *b, char *s1)
{
int i;
if(s0)
bs = seprint(bs, be, "%s", s0);
if(b == nil)
bs = seprint(bs, be, "nil");
else {
bs = seprint(bs, be, "[ ");
for(i=0; i<b->len; i++)
bs = seprint(bs, be, "%x ", b->data[i]);
bs = seprint(bs, be, "]");
}
if(s1)
bs = seprint(bs, be, "%s", s1);
return bs;
}
static char*
msgPrint(char *buf, int n, Msg *m)
{
int i;
char *bs = buf, *be = buf+n;
switch(m->tag) {
default:
bs = seprint(bs, be, "unknown %d\n", m->tag);
break;
case HClientHello:
bs = seprint(bs, be, "ClientHello\n");
bs = seprint(bs, be, "\tversion: %.4x\n", m->u.clientHello.version);
bs = seprint(bs, be, "\trandom: ");
for(i=0; i<RandomSize; i++)
bs = seprint(bs, be, "%.2x", m->u.clientHello.random[i]);
bs = seprint(bs, be, "\n");
bs = bytesPrint(bs, be, "\tsid: ", m->u.clientHello.sid, "\n");
bs = intsPrint(bs, be, "\tciphers: ", m->u.clientHello.ciphers, "\n");
bs = bytesPrint(bs, be, "\tcompressors: ", m->u.clientHello.compressors, "\n");
if(m->u.clientHello.extensions != nil)
bs = bytesPrint(bs, be, "\textensions: ", m->u.clientHello.extensions, "\n");
break;
case HServerHello:
bs = seprint(bs, be, "ServerHello\n");
bs = seprint(bs, be, "\tversion: %.4x\n", m->u.serverHello.version);
bs = seprint(bs, be, "\trandom: ");
for(i=0; i<RandomSize; i++)
bs = seprint(bs, be, "%.2x", m->u.serverHello.random[i]);
bs = seprint(bs, be, "\n");
bs = bytesPrint(bs, be, "\tsid: ", m->u.serverHello.sid, "\n");
bs = seprint(bs, be, "\tcipher: %.4x\n", m->u.serverHello.cipher);
bs = seprint(bs, be, "\tcompressor: %.2x\n", m->u.serverHello.compressor);
if(m->u.serverHello.extensions != nil)
bs = bytesPrint(bs, be, "\textensions: ", m->u.serverHello.extensions, "\n");
break;
case HCertificate:
bs = seprint(bs, be, "Certificate\n");
for(i=0; i<m->u.certificate.ncert; i++)
bs = bytesPrint(bs, be, "\t", m->u.certificate.certs[i], "\n");
break;
case HCertificateRequest:
bs = seprint(bs, be, "CertificateRequest\n");
bs = bytesPrint(bs, be, "\ttypes: ", m->u.certificateRequest.types, "\n");
if(m->u.certificateRequest.sigalgs != nil)
bs = intsPrint(bs, be, "\tsigalgs: ", m->u.certificateRequest.sigalgs, "\n");
bs = seprint(bs, be, "\tcertificateauthorities\n");
for(i=0; i<m->u.certificateRequest.nca; i++)
bs = bytesPrint(bs, be, "\t\t", m->u.certificateRequest.cas[i], "\n");
break;
case HCertificateVerify:
bs = seprint(bs, be, "HCertificateVerify\n");
if(m->u.certificateVerify.sigalg != 0)
bs = seprint(bs, be, "\tsigalg: %.4x\n", m->u.certificateVerify.sigalg);
bs = bytesPrint(bs, be, "\tsignature: ", m->u.certificateVerify.signature,"\n");
break;
case HServerHelloDone:
bs = seprint(bs, be, "ServerHelloDone\n");
break;
case HServerKeyExchange:
bs = seprint(bs, be, "HServerKeyExchange\n");
if(m->u.serverKeyExchange.pskid != nil)
bs = bytesPrint(bs, be, "\tpskid: ", m->u.serverKeyExchange.pskid, "\n");
if(m->u.serverKeyExchange.dh_parameters == nil)
break;
if(m->u.serverKeyExchange.curve != 0){
bs = seprint(bs, be, "\tcurve: %.4x\n", m->u.serverKeyExchange.curve);
} else {
bs = bytesPrint(bs, be, "\tdh_p: ", m->u.serverKeyExchange.dh_p, "\n");
bs = bytesPrint(bs, be, "\tdh_g: ", m->u.serverKeyExchange.dh_g, "\n");
}
bs = bytesPrint(bs, be, "\tdh_Ys: ", m->u.serverKeyExchange.dh_Ys, "\n");
if(m->u.serverKeyExchange.sigalg != 0)
bs = seprint(bs, be, "\tsigalg: %.4x\n", m->u.serverKeyExchange.sigalg);
bs = bytesPrint(bs, be, "\tdh_parameters: ", m->u.serverKeyExchange.dh_parameters, "\n");
bs = bytesPrint(bs, be, "\tdh_signature: ", m->u.serverKeyExchange.dh_signature, "\n");
break;
case HClientKeyExchange:
bs = seprint(bs, be, "HClientKeyExchange\n");
if(m->u.clientKeyExchange.pskid != nil)
bs = bytesPrint(bs, be, "\tpskid: ", m->u.clientKeyExchange.pskid, "\n");
if(m->u.clientKeyExchange.key != nil)
bs = bytesPrint(bs, be, "\tkey: ", m->u.clientKeyExchange.key, "\n");
break;
case HFinished:
bs = seprint(bs, be, "HFinished\n");
for(i=0; i<m->u.finished.n; i++)
bs = seprint(bs, be, "%.2x", m->u.finished.verify[i]);
bs = seprint(bs, be, "\n");
break;
}
USED(bs);
return buf;
}
static void
tlsError(TlsConnection *c, int err, char *fmt, ...)
{
char msg[512];
va_list arg;
va_start(arg, fmt);
vseprint(msg, msg+sizeof(msg), fmt, arg);
va_end(arg);
if(c->trace)
c->trace("tlsError: %s\n", msg);
if(c->erred)
fprint(2, "double error: %r, %s", msg);
else
errstr(msg, sizeof(msg));
c->erred = 1;
fprint(c->ctl, "alert %d", err);
}
// commit to specific version number
static int
setVersion(TlsConnection *c, int version)
{
if(version > MaxProtoVersion || version < MinProtoVersion)
return -1;
if(version > c->version)
version = c->version;
if(version == SSL3Version) {
c->version = version;
c->finished.n = SSL3FinishedLen;
}else {
c->version = version;
c->finished.n = TLSFinishedLen;
}
return fprint(c->ctl, "version 0x%x", version);
}
// confirm that received Finished message matches the expected value
static int
finishedMatch(TlsConnection *c, Finished *f)
{
return tsmemcmp(f->verify, c->finished.verify, f->n) == 0;
}
// free memory associated with TlsConnection struct
// (but don't close the TLS channel itself)
static void
tlsConnectionFree(TlsConnection *c)
{
if(c == nil)
return;
dh_finish(&c->sec->dh, nil);
mpfree(c->sec->ec.Q.a.x);
mpfree(c->sec->ec.Q.a.y);
mpfree(c->sec->ec.Q.d);
ecdomfree(&c->sec->ec.dom);
factotum_rsa_close(c->sec->rpc);
rsapubfree(c->sec->rsapub);
freebytes(c->cert);
memset(c, 0, sizeof(*c));
free(c);
}
//================= cipher choices ========================
static int
isDHE(int tlsid)
{
switch(tlsid){
case TLS_DHE_RSA_WITH_AES_128_GCM_SHA256:
case TLS_DHE_RSA_WITH_AES_128_CBC_SHA256:
case TLS_DHE_RSA_WITH_AES_128_CBC_SHA:
case TLS_DHE_RSA_WITH_AES_256_CBC_SHA:
case TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA:
case TLS_DHE_RSA_WITH_CHACHA20_POLY1305:
case GOOGLE_DHE_RSA_WITH_CHACHA20_POLY1305:
return 1;
}
return 0;
}
static int
isECDHE(int tlsid)
{
switch(tlsid){
case TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305:
case TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305:
case GOOGLE_ECDHE_ECDSA_WITH_CHACHA20_POLY1305:
case GOOGLE_ECDHE_RSA_WITH_CHACHA20_POLY1305:
case TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
case TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256:
case TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256:
case TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256:
case TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA:
case TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA:
return 1;
}
return 0;
}
static int
isPSK(int tlsid)
{
switch(tlsid){
case TLS_PSK_WITH_CHACHA20_POLY1305:
case TLS_PSK_WITH_AES_128_CBC_SHA256:
case TLS_PSK_WITH_AES_128_CBC_SHA:
return 1;
}
return 0;
}
static int
isECDSA(int tlsid)
{
switch(tlsid){
case TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305:
case GOOGLE_ECDHE_ECDSA_WITH_CHACHA20_POLY1305:
case TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
case TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256:
return 1;
}
return 0;
}
static int
setAlgs(TlsConnection *c, int a)
{
int i;
for(i = 0; i < nelem(cipherAlgs); i++){
if(cipherAlgs[i].tlsid == a){
c->cipher = a;
c->enc = cipherAlgs[i].enc;
c->digest = cipherAlgs[i].digest;
c->nsecret = cipherAlgs[i].nsecret;
if(c->nsecret > MaxKeyData)
return 0;
return 1;
}
}
return 0;
}
static int
okCipher(Ints *cv, int ispsk, int canec)
{
int i, c;
for(i = 0; i < nelem(cipherAlgs); i++) {
c = cipherAlgs[i].tlsid;
if(!cipherAlgs[i].ok || isECDSA(c) || isDHE(c))
continue;
if(isPSK(c) != ispsk)
continue;
if(isECDHE(c) && !canec)
continue;
if(lookupid(cv, c) >= 0)
return c;
}
return -1;
}
static int
okCompression(Bytes *cv)
{
int i, c;
for(i = 0; i < nelem(compressors); i++) {
c = compressors[i];
if(memchr(cv->data, c, cv->len) != nil)
return c;
}
return -1;
}
static Lock ciphLock;
static int nciphers;
static int
initCiphers(void)
{
enum {MaxAlgF = 1024, MaxAlgs = 10};
char s[MaxAlgF], *flds[MaxAlgs];
int i, j, n, ok;
lock(&ciphLock);
if(nciphers){
unlock(&ciphLock);
return nciphers;
}
j = open("#a/tls/encalgs", OREAD|OCEXEC);
if(j < 0){
werrstr("can't open #a/tls/encalgs: %r");
goto out;
}
n = read(j, s, MaxAlgF-1);
close(j);
if(n <= 0){
werrstr("nothing in #a/tls/encalgs: %r");
goto out;
}
s[n] = 0;
n = getfields(s, flds, MaxAlgs, 1, " \t\r\n");
for(i = 0; i < nelem(cipherAlgs); i++){
ok = 0;
for(j = 0; j < n; j++){
if(strcmp(cipherAlgs[i].enc, flds[j]) == 0){
ok = 1;
break;
}
}
cipherAlgs[i].ok = ok;
}
j = open("#a/tls/hashalgs", OREAD|OCEXEC);
if(j < 0){
werrstr("can't open #a/tls/hashalgs: %r");
goto out;
}
n = read(j, s, MaxAlgF-1);
close(j);
if(n <= 0){
werrstr("nothing in #a/tls/hashalgs: %r");
goto out;
}
s[n] = 0;
n = getfields(s, flds, MaxAlgs, 1, " \t\r\n");
for(i = 0; i < nelem(cipherAlgs); i++){
ok = 0;
for(j = 0; j < n; j++){
if(strcmp(cipherAlgs[i].digest, flds[j]) == 0){
ok = 1;
break;
}
}
cipherAlgs[i].ok &= ok;
if(cipherAlgs[i].ok)
nciphers++;
}
out:
unlock(&ciphLock);
return nciphers;
}
static Ints*
makeciphers(int ispsk)
{
Ints *is;
int i, j;
is = newints(nciphers);
j = 0;
for(i = 0; i < nelem(cipherAlgs); i++)
if(cipherAlgs[i].ok && isPSK(cipherAlgs[i].tlsid) == ispsk)
is->data[j++] = cipherAlgs[i].tlsid;
is->len = j;
return is;
}
//================= security functions ========================
// given a public key, set up connection to factotum
// for using corresponding private key
static AuthRpc*
factotum_rsa_open(RSApub *rsapub)
{
int afd;
char *s;
mpint *n;
AuthRpc *rpc;
// start talking to factotum
if((afd = open("/mnt/factotum/rpc", ORDWR|OCEXEC)) < 0)
return nil;
if((rpc = auth_allocrpc(afd)) == nil){
close(afd);
return nil;
}
s = "proto=rsa service=tls role=client";
if(auth_rpc(rpc, "start", s, strlen(s)) == ARok){
// roll factotum keyring around to match public key
n = mpnew(0);
while(auth_rpc(rpc, "read", nil, 0) == ARok){
if(strtomp(rpc->arg, nil, 16, n) != nil
&& mpcmp(n, rsapub->n) == 0){
mpfree(n);
return rpc;
}
}
mpfree(n);
}
factotum_rsa_close(rpc);
return nil;
}
static mpint*
factotum_rsa_decrypt(AuthRpc *rpc, mpint *cipher)
{
char *p;
int rv;
if(cipher == nil)
return nil;
p = mptoa(cipher, 16, nil, 0);
mpfree(cipher);
if(p == nil)
return nil;
rv = auth_rpc(rpc, "write", p, strlen(p));
free(p);
if(rv != ARok || auth_rpc(rpc, "read", nil, 0) != ARok)
return nil;
return strtomp(rpc->arg, nil, 16, nil);
}
static void
factotum_rsa_close(AuthRpc *rpc)
{
if(rpc == nil)
return;
close(rpc->afd);
auth_freerpc(rpc);
}
// buf ^= prf
static void
tlsP(uchar *buf, int nbuf, uchar *key, int nkey, uchar *label, int nlabel, uchar *seed, int nseed,
DigestState* (*x)(uchar*, ulong, uchar*, ulong, uchar*, DigestState*), int xlen)
{
uchar ai[SHA2_256dlen], tmp[SHA2_256dlen];
DigestState *s;
int n, i;
assert(xlen <= sizeof(ai) && xlen <= sizeof(tmp));
// generate a1
s = x(label, nlabel, key, nkey, nil, nil);
x(seed, nseed, key, nkey, ai, s);
while(nbuf > 0) {
s = x(ai, xlen, key, nkey, nil, nil);
s = x(label, nlabel, key, nkey, nil, s);
x(seed, nseed, key, nkey, tmp, s);
n = xlen;
if(n > nbuf)
n = nbuf;
for(i = 0; i < n; i++)
buf[i] ^= tmp[i];
buf += n;
nbuf -= n;
x(ai, xlen, key, nkey, tmp, nil);
memmove(ai, tmp, xlen);
}
}
// fill buf with md5(args)^sha1(args)
static void
tls10PRF(uchar *buf, int nbuf, uchar *key, int nkey, char *label, uchar *seed, int nseed)
{
int nlabel = strlen(label);
int n = (nkey + 1) >> 1;
memset(buf, 0, nbuf);
tlsP(buf, nbuf, key, n, (uchar*)label, nlabel, seed, nseed,
hmac_md5, MD5dlen);
tlsP(buf, nbuf, key+nkey-n, n, (uchar*)label, nlabel, seed, nseed,
hmac_sha1, SHA1dlen);
}
static void
tls12PRF(uchar *buf, int nbuf, uchar *key, int nkey, char *label, uchar *seed, int nseed)
{
memset(buf, 0, nbuf);
tlsP(buf, nbuf, key, nkey, (uchar*)label, strlen(label), seed, nseed,
hmac_sha2_256, SHA2_256dlen);
}
static void
sslPRF(uchar *buf, int nbuf, uchar *key, int nkey, char *label, uchar *seed, int nseed)
{
uchar sha1dig[SHA1dlen], md5dig[MD5dlen], tmp[26];
DigestState *s;
int i, n, len;
USED(label);
len = 1;
while(nbuf > 0){
if(len > 26)
return;
for(i = 0; i < len; i++)
tmp[i] = 'A' - 1 + len;
s = sha1(tmp, len, nil, nil);
s = sha1(key, nkey, nil, s);
sha1(seed, nseed, sha1dig, s);
s = md5(key, nkey, nil, nil);
md5(sha1dig, SHA1dlen, md5dig, s);
n = MD5dlen;
if(n > nbuf)
n = nbuf;
memmove(buf, md5dig, n);
buf += n;
nbuf -= n;
len++;
}
}
static void
sslSetFinished(TlsSec *sec, HandshakeHash hsh, uchar *finished, int isclient)
{
DigestState *s;
uchar h0[MD5dlen], h1[SHA1dlen], pad[48];
char *label;
if(isclient)
label = "CLNT";
else
label = "SRVR";
md5((uchar*)label, 4, nil, &hsh.md5);
md5(sec->sec, MasterSecretSize, nil, &hsh.md5);
memset(pad, 0x36, 48);
md5(pad, 48, nil, &hsh.md5);
md5(nil, 0, h0, &hsh.md5);
memset(pad, 0x5C, 48);
s = md5(sec->sec, MasterSecretSize, nil, nil);
s = md5(pad, 48, nil, s);
md5(h0, MD5dlen, finished, s);
sha1((uchar*)label, 4, nil, &hsh.sha1);
sha1(sec->sec, MasterSecretSize, nil, &hsh.sha1);
memset(pad, 0x36, 40);
sha1(pad, 40, nil, &hsh.sha1);
sha1(nil, 0, h1, &hsh.sha1);
memset(pad, 0x5C, 40);
s = sha1(sec->sec, MasterSecretSize, nil, nil);
s = sha1(pad, 40, nil, s);
sha1(h1, SHA1dlen, finished + MD5dlen, s);
}
// fill "finished" arg with md5(args)^sha1(args)
static void
tls10SetFinished(TlsSec *sec, HandshakeHash hsh, uchar *finished, int isclient)
{
uchar h[MD5dlen+SHA1dlen];
char *label;
// get current hash value, but allow further messages to be hashed in
md5(nil, 0, h, &hsh.md5);
sha1(nil, 0, h+MD5dlen, &hsh.sha1);
if(isclient)
label = "client finished";
else
label = "server finished";
tls10PRF(finished, TLSFinishedLen, sec->sec, MasterSecretSize, label, h, sizeof(h));
}
static void
tls12SetFinished(TlsSec *sec, HandshakeHash hsh, uchar *finished, int isclient)
{
uchar seed[SHA2_256dlen];
char *label;
// get current hash value, but allow further messages to be hashed in
sha2_256(nil, 0, seed, &hsh.sha2_256);
if(isclient)
label = "client finished";
else
label = "server finished";
tls12PRF(finished, TLSFinishedLen, sec->sec, MasterSecretSize, label, seed, SHA2_256dlen);
}
static void
tlsSecInits(TlsSec *sec, int cvers, uchar *crandom)
{
memset(sec, 0, sizeof(*sec));
sec->clientVers = cvers;
memmove(sec->crandom, crandom, RandomSize);
// putting time()'s output to the first 4 bytes is no
// longer recommended and is not useful
genrandom(sec->srandom, RandomSize);
}
static int
tlsSecRSAs(TlsSec *sec, Bytes *epm)
{
Bytes *pm;
if(epm == nil){
werrstr("no encrypted premaster secret");
return -1;
}
// if the client messed up, just continue as if everything is ok,
// to prevent attacks to check for correctly formatted messages.
pm = pkcs1_decrypt(sec, epm);
if(pm == nil || pm->len != MasterSecretSize || get16(pm->data) != sec->clientVers){
freebytes(pm);
pm = newbytes(MasterSecretSize);
genrandom(pm->data, pm->len);
}
setMasterSecret(sec, pm);
return 0;
}
static Bytes*
tlsSecECDHEs1(TlsSec *sec)
{
ECdomain *dom = &sec->ec.dom;
ECpriv *Q = &sec->ec.Q;
Bytes *par;
int n;
if(sec->nc == nil)
return nil;
if(sec->nc->tlsid == X25519){
par = newbytes(1+2+1+32);
par->data[0] = 3;
put16(par->data+1, X25519);
par->data[3] = 32;
curve25519_dh_new(sec->X, par->data+4);
}else{
ecdominit(dom, sec->nc->init);
memset(Q, 0, sizeof(*Q));
Q->a.x = mpnew(0);
Q->a.y = mpnew(0);
Q->d = mpnew(0);
ecgen(dom, Q);
n = 1 + 2*((mpsignif(dom->p)+7)/8);
par = newbytes(1+2+1+n);
par->data[0] = 3;
put16(par->data+1, sec->nc->tlsid);
n = ecencodepub(dom, &Q->a, par->data+4, par->len-4);
par->data[3] = n;
par->len = 1+2+1+n;
}
return par;
}
static int
tlsSecECDHEs2(TlsSec *sec, Bytes *Yc)
{
ECdomain *dom = &sec->ec.dom;
ECpriv *Q = &sec->ec.Q;
ECpoint K;
ECpub *Y;
Bytes *Z;
if(Yc == nil){
werrstr("no public key");
return -1;
}
if(sec->nc->tlsid == X25519){
if(Yc->len != 32){
werrstr("bad public key");
return -1;
}
Z = newbytes(32);
if(!curve25519_dh_finish(sec->X, Yc->data, Z->data)){
werrstr("unlucky shared key");
freebytes(Z);
return -1;
}
setMasterSecret(sec, Z);
}else{
if((Y = ecdecodepub(dom, Yc->data, Yc->len)) == nil){
werrstr("bad public key");
return -1;
}
memset(&K, 0, sizeof(K));
K.x = mpnew(0);
K.y = mpnew(0);
ecmul(dom, Y, Q->d, &K);
setMasterSecret(sec, mptobytes(K.x, (mpsignif(dom->p)+7)/8));
mpfree(K.x);
mpfree(K.y);
ecpubfree(Y);
}
return 0;
}
static void
tlsSecInitc(TlsSec *sec, int cvers)
{
memset(sec, 0, sizeof(*sec));
sec->clientVers = cvers;
// see the comment on tlsSecInits
genrandom(sec->crandom, RandomSize);
}
static Bytes*
tlsSecRSAc(TlsSec *sec, uchar *cert, int ncert)
{
RSApub *pub;
Bytes *pm, *epm;
pub = X509toRSApub(cert, ncert, nil, 0);
if(pub == nil){
werrstr("invalid x509/rsa certificate");
return nil;
}
pm = newbytes(MasterSecretSize);
put16(pm->data, sec->clientVers);
genrandom(pm->data+2, MasterSecretSize - 2);
epm = pkcs1_encrypt(pm, pub);
setMasterSecret(sec, pm);
rsapubfree(pub);
return epm;
}
static int
tlsSecFinished(TlsSec *sec, HandshakeHash hsh, uchar *fin, int nfin, int isclient)
{
if(sec->nfin != nfin){
werrstr("invalid finished exchange");
return -1;
}
hsh.md5.malloced = 0;
hsh.sha1.malloced = 0;
hsh.sha2_256.malloced = 0;
(*sec->setFinished)(sec, hsh, fin, isclient);
return 0;
}
static void
tlsSecVers(TlsSec *sec, int v)
{
if(v == SSL3Version){
sec->setFinished = sslSetFinished;
sec->nfin = SSL3FinishedLen;
sec->prf = sslPRF;
}else if(v < TLS12Version) {
sec->setFinished = tls10SetFinished;
sec->nfin = TLSFinishedLen;
sec->prf = tls10PRF;
}else {
sec->setFinished = tls12SetFinished;
sec->nfin = TLSFinishedLen;
sec->prf = tls12PRF;
}
}
static int
setSecrets(TlsConnection *c, int isclient)
{
uchar kd[MaxKeyData], seed[2*RandomSize];
char *secrets;
int rv;
assert(c->nsecret <= sizeof(kd));
secrets = emalloc(2*c->nsecret);
memmove(seed, c->sec->srandom, RandomSize);
memmove(seed+RandomSize, c->sec->crandom, RandomSize);
/*
* generate secret keys from the master secret.
*
* different cipher selections will require different amounts
* of key expansion and use of key expansion data,
* but it's all generated using the same function.
*/
(*c->sec->prf)(kd, c->nsecret, c->sec->sec, MasterSecretSize, "key expansion",
seed, sizeof(seed));
enc64(secrets, 2*c->nsecret, kd, c->nsecret);
memset(kd, 0, c->nsecret);
rv = fprint(c->ctl, "secret %s %s %d %s", c->digest, c->enc, isclient, secrets);
memset(secrets, 0, 2*c->nsecret);
free(secrets);
return rv;
}
/*
* set the master secret from the pre-master secret,
* destroys premaster.
*/
static void
setMasterSecret(TlsSec *sec, Bytes *pm)
{
uchar seed[2*RandomSize];
if(sec->psklen > 0){
Bytes *opm = pm;
uchar *p;
/* concatenate psk to pre-master secret */
pm = newbytes(4 + opm->len + sec->psklen);
p = pm->data;
put16(p, opm->len), p += 2;
memmove(p, opm->data, opm->len), p += opm->len;
put16(p, sec->psklen), p += 2;
memmove(p, sec->psk, sec->psklen);
memset(opm->data, 0, opm->len);
freebytes(opm);
}
memmove(seed, sec->crandom, RandomSize);
memmove(seed+RandomSize, sec->srandom, RandomSize);
(*sec->prf)(sec->sec, MasterSecretSize, pm->data, pm->len, "master secret",
seed, sizeof(seed));
memset(pm->data, 0, pm->len);
freebytes(pm);
}
static int
digestDHparams(TlsSec *sec, Bytes *par, uchar digest[MAXdlen], int sigalg)
{
int hashalg = (sigalg>>8) & 0xFF;
int digestlen;
Bytes *blob;
blob = newbytes(2*RandomSize + par->len);
memmove(blob->data+0*RandomSize, sec->crandom, RandomSize);
memmove(blob->data+1*RandomSize, sec->srandom, RandomSize);
memmove(blob->data+2*RandomSize, par->data, par->len);
if(hashalg == 0){
digestlen = MD5dlen+SHA1dlen;
md5(blob->data, blob->len, digest, nil);
sha1(blob->data, blob->len, digest+MD5dlen, nil);
} else {
digestlen = -1;
if(hashalg < nelem(hashfun) && hashfun[hashalg].fun != nil){
digestlen = hashfun[hashalg].len;
(*hashfun[hashalg].fun)(blob->data, blob->len, digest, nil);
}
}
freebytes(blob);
return digestlen;
}
static char*
verifyDHparams(TlsSec *sec, Bytes *par, Bytes *cert, Bytes *sig, int sigalg)
{
uchar digest[MAXdlen];
int digestlen;
ECdomain dom;
ECpub *ecpk;
RSApub *rsapk;
char *err;
if(par == nil || par->len <= 0)
return "no DH parameters";
if(sig == nil || sig->len <= 0){
if(sec->psklen > 0)
return nil;
return "no signature";
}
if(cert == nil)
return "no certificate";
digestlen = digestDHparams(sec, par, digest, sigalg);
if(digestlen <= 0)
return "unknown signature digest algorithm";
switch(sigalg & 0xFF){
case 0x01:
rsapk = X509toRSApub(cert->data, cert->len, nil, 0);
if(rsapk == nil)
return "bad certificate";
err = X509rsaverifydigest(sig->data, sig->len, digest, digestlen, rsapk);
rsapubfree(rsapk);
break;
case 0x03:
ecpk = X509toECpub(cert->data, cert->len, nil, 0, &dom);
if(ecpk == nil)
return "bad certificate";
err = X509ecdsaverifydigest(sig->data, sig->len, digest, digestlen, &dom, ecpk);
ecdomfree(&dom);
ecpubfree(ecpk);
break;
default:
err = "signaure algorithm not RSA or ECDSA";
}
return err;
}
// encrypt data according to PKCS#1, /lib/rfc/rfc2437 9.1.2.1
static Bytes*
pkcs1_encrypt(Bytes* data, RSApub* key)
{
mpint *x, *y;
x = pkcs1padbuf(data->data, data->len, key->n, 2);
if(x == nil)
return nil;
y = rsaencrypt(key, x, nil);
mpfree(x);
data = newbytes((mpsignif(key->n)+7)/8);
mptober(y, data->data, data->len);
mpfree(y);
return data;
}
// decrypt data according to PKCS#1, with given key.
static Bytes*
pkcs1_decrypt(TlsSec *sec, Bytes *data)
{
mpint *y;
if(data->len != (mpsignif(sec->rsapub->n)+7)/8)
return nil;
y = factotum_rsa_decrypt(sec->rpc, bytestomp(data));
if(y == nil)
return nil;
data = mptobytes(y, (mpsignif(y)+7)/8);
mpfree(y);
if((data->len = pkcs1unpadbuf(data->data, data->len, sec->rsapub->n, 2)) < 0){
freebytes(data);
return nil;
}
return data;
}
static Bytes*
pkcs1_sign(TlsSec *sec, uchar *digest, int digestlen, int sigalg)
{
int hashalg = (sigalg>>8)&0xFF;
mpint *signedMP;
Bytes *signature;
uchar buf[128];
if(hashalg > 0 && hashalg < nelem(hashfun) && hashfun[hashalg].len == digestlen)
digestlen = asn1encodedigest(hashfun[hashalg].fun, digest, buf, sizeof(buf));
else if(digestlen == MD5dlen+SHA1dlen)
memmove(buf, digest, digestlen);
else
digestlen = -1;
if(digestlen <= 0){
werrstr("bad digest algorithm");
return nil;
}
signedMP = factotum_rsa_decrypt(sec->rpc, pkcs1padbuf(buf, digestlen, sec->rsapub->n, 1));
if(signedMP == nil)
return nil;
signature = mptobytes(signedMP, (mpsignif(sec->rsapub->n)+7)/8);
mpfree(signedMP);
return signature;
}
//================= general utility functions ========================
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 void *
erealloc(void *ReallocP, int ReallocN)
{
if(ReallocN == 0)
ReallocN = 1;
if(ReallocP == nil)
ReallocP = emalloc(ReallocN);
else if((ReallocP = realloc(ReallocP, ReallocN)) == nil)
sysfatal("out of memory");
setrealloctag(ReallocP, getcallerpc(&ReallocP));
return(ReallocP);
}
static void
put32(uchar *p, u32int x)
{
p[0] = x>>24;
p[1] = x>>16;
p[2] = x>>8;
p[3] = x;
}
static void
put24(uchar *p, int x)
{
p[0] = x>>16;
p[1] = x>>8;
p[2] = x;
}
static void
put16(uchar *p, int x)
{
p[0] = x>>8;
p[1] = x;
}
static int
get24(uchar *p)
{
return (p[0]<<16)|(p[1]<<8)|p[2];
}
static int
get16(uchar *p)
{
return (p[0]<<8)|p[1];
}
static Bytes*
newbytes(int len)
{
Bytes* ans;
if(len < 0)
abort();
ans = emalloc(sizeof(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);
}
static mpint*
bytestomp(Bytes* bytes)
{
return betomp(bytes->data, bytes->len, nil);
}
/*
* Convert mpint* to Bytes, putting high order byte first.
*/
static Bytes*
mptobytes(mpint *big, int len)
{
Bytes* ans;
if(len == 0) len++;
ans = newbytes(len);
mptober(big, ans->data, ans->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 = emalloc(sizeof(Ints) + len*sizeof(int));
ans->len = len;
return ans;
}
static void
freeints(Ints* b)
{
free(b);
}
static int
lookupid(Ints* b, int id)
{
int i;
for(i=0; i<b->len; i++)
if(b->data[i] == id)
return i;
return -1;
}