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putty/pageant.c

1722 строки
46 KiB
C
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/*
* pageant.c: cross-platform code to implement Pageant.
*/
#include <stddef.h>
#include <stdlib.h>
#include <assert.h>
#include "putty.h"
#include "ssh.h"
#include "pageant.h"
/*
* We need this to link with the RSA code, because rsaencrypt()
* pads its data with random bytes. Since we only use rsadecrypt()
* and the signing functions, which are deterministic, this should
* never be called.
*
* If it _is_ called, there is a _serious_ problem, because it
* won't generate true random numbers. So we must scream, panic,
* and exit immediately if that should happen.
*/
int random_byte(void)
{
modalfatalbox("Internal error: attempt to use random numbers in Pageant");
exit(0);
return 0; /* unreachable, but placate optimiser */
}
static int pageant_local = FALSE;
/*
* rsakeys stores SSH-1 RSA keys. ssh2keys stores all SSH-2 keys.
*/
static tree234 *rsakeys, *ssh2keys;
/*
* Blob structure for passing to the asymmetric SSH-2 key compare
* function, prototyped here.
*/
struct blob {
const unsigned char *blob;
int len;
};
static int cmpkeys_ssh2_asymm(void *av, void *bv);
/*
* Key comparison function for the 2-3-4 tree of RSA keys.
*/
static int cmpkeys_rsa(void *av, void *bv)
{
struct RSAKey *a = (struct RSAKey *) av;
struct RSAKey *b = (struct RSAKey *) bv;
Bignum am, bm;
int alen, blen;
am = a->modulus;
bm = b->modulus;
/*
* Compare by length of moduli.
*/
alen = bignum_bitcount(am);
blen = bignum_bitcount(bm);
if (alen > blen)
return +1;
else if (alen < blen)
return -1;
/*
* Now compare by moduli themselves.
*/
alen = (alen + 7) / 8; /* byte count */
while (alen-- > 0) {
int abyte, bbyte;
abyte = bignum_byte(am, alen);
bbyte = bignum_byte(bm, alen);
if (abyte > bbyte)
return +1;
else if (abyte < bbyte)
return -1;
}
/*
* Give up.
*/
return 0;
}
/*
* Key comparison function for the 2-3-4 tree of SSH-2 keys.
*/
static int cmpkeys_ssh2(void *av, void *bv)
{
struct ssh2_userkey *a = (struct ssh2_userkey *) av;
struct ssh2_userkey *b = (struct ssh2_userkey *) bv;
int i;
int alen, blen;
unsigned char *ablob, *bblob;
int c;
/*
* Compare purely by public blob.
*/
ablob = a->alg->public_blob(a->data, &alen);
bblob = b->alg->public_blob(b->data, &blen);
c = 0;
for (i = 0; i < alen && i < blen; i++) {
if (ablob[i] < bblob[i]) {
c = -1;
break;
} else if (ablob[i] > bblob[i]) {
c = +1;
break;
}
}
if (c == 0 && i < alen)
c = +1; /* a is longer */
if (c == 0 && i < blen)
c = -1; /* a is longer */
sfree(ablob);
sfree(bblob);
return c;
}
/*
* Key comparison function for looking up a blob in the 2-3-4 tree
* of SSH-2 keys.
*/
static int cmpkeys_ssh2_asymm(void *av, void *bv)
{
struct blob *a = (struct blob *) av;
struct ssh2_userkey *b = (struct ssh2_userkey *) bv;
int i;
int alen, blen;
const unsigned char *ablob;
unsigned char *bblob;
int c;
/*
* Compare purely by public blob.
*/
ablob = a->blob;
alen = a->len;
bblob = b->alg->public_blob(b->data, &blen);
c = 0;
for (i = 0; i < alen && i < blen; i++) {
if (ablob[i] < bblob[i]) {
c = -1;
break;
} else if (ablob[i] > bblob[i]) {
c = +1;
break;
}
}
if (c == 0 && i < alen)
c = +1; /* a is longer */
if (c == 0 && i < blen)
c = -1; /* a is longer */
sfree(bblob);
return c;
}
/*
* Create an SSH-1 key list in a malloc'ed buffer; return its
* length.
*/
void *pageant_make_keylist1(int *length)
{
int i, nkeys, len;
struct RSAKey *key;
unsigned char *blob, *p, *ret;
int bloblen;
/*
* Count up the number and length of keys we hold.
*/
len = 4;
nkeys = 0;
for (i = 0; NULL != (key = index234(rsakeys, i)); i++) {
nkeys++;
blob = rsa_public_blob(key, &bloblen);
len += bloblen;
sfree(blob);
len += 4 + strlen(key->comment);
}
/* Allocate the buffer. */
p = ret = snewn(len, unsigned char);
if (length) *length = len;
PUT_32BIT(p, nkeys);
p += 4;
for (i = 0; NULL != (key = index234(rsakeys, i)); i++) {
blob = rsa_public_blob(key, &bloblen);
memcpy(p, blob, bloblen);
p += bloblen;
sfree(blob);
PUT_32BIT(p, strlen(key->comment));
memcpy(p + 4, key->comment, strlen(key->comment));
p += 4 + strlen(key->comment);
}
assert(p - ret == len);
return ret;
}
/*
* Create an SSH-2 key list in a malloc'ed buffer; return its
* length.
*/
void *pageant_make_keylist2(int *length)
{
struct ssh2_userkey *key;
int i, len, nkeys;
unsigned char *blob, *p, *ret;
int bloblen;
/*
* Count up the number and length of keys we hold.
*/
len = 4;
nkeys = 0;
for (i = 0; NULL != (key = index234(ssh2keys, i)); i++) {
nkeys++;
len += 4; /* length field */
blob = key->alg->public_blob(key->data, &bloblen);
len += bloblen;
sfree(blob);
len += 4 + strlen(key->comment);
}
/* Allocate the buffer. */
p = ret = snewn(len, unsigned char);
if (length) *length = len;
/*
* Packet header is the obvious five bytes, plus four
* bytes for the key count.
*/
PUT_32BIT(p, nkeys);
p += 4;
for (i = 0; NULL != (key = index234(ssh2keys, i)); i++) {
blob = key->alg->public_blob(key->data, &bloblen);
PUT_32BIT(p, bloblen);
p += 4;
memcpy(p, blob, bloblen);
p += bloblen;
sfree(blob);
PUT_32BIT(p, strlen(key->comment));
memcpy(p + 4, key->comment, strlen(key->comment));
p += 4 + strlen(key->comment);
}
assert(p - ret == len);
return ret;
}
char *fingerprint_ssh2_blob(const void *blob, int bloblen)
{
unsigned char digest[16];
char fingerprint_str[16*3];
unsigned stringlen;
int i;
MD5Simple(blob, bloblen, digest);
for (i = 0; i < 16; i++)
sprintf(fingerprint_str + i*3, "%02x%s", digest[i], i==15 ? "" : ":");
stringlen = GET_32BIT((const unsigned char *)blob);
if (stringlen < bloblen-4)
return dupprintf("%.*s %s", (int)stringlen, (const char *)blob + 4,
fingerprint_str);
else
return dupstr(fingerprint_str);
}
static void plog(void *logctx, pageant_logfn_t logfn, const char *fmt, ...)
#ifdef __GNUC__
__attribute__ ((format (printf, 3, 4)))
#endif
;
static void plog(void *logctx, pageant_logfn_t logfn, const char *fmt, ...)
{
/*
* This is the wrapper that takes a variadic argument list and
* turns it into the va_list that the log function really expects.
* It's safe to call this with logfn==NULL, because we
* double-check that below; but if you're going to do lots of work
* before getting here (such as looping, or hashing things) then
* you should probably check logfn manually before doing that.
*/
if (logfn) {
va_list ap;
va_start(ap, fmt);
logfn(logctx, fmt, ap);
va_end(ap);
}
}
void *pageant_handle_msg(const void *msg, int msglen, int *outlen,
void *logctx, pageant_logfn_t logfn)
{
const unsigned char *p = msg;
const unsigned char *msgend;
unsigned char *ret = snewn(AGENT_MAX_MSGLEN, unsigned char);
int type;
const char *fail_reason;
msgend = p + msglen;
/*
* Get the message type.
*/
if (msgend < p+1) {
fail_reason = "message contained no type code";
goto failure;
}
type = *p++;
switch (type) {
case SSH1_AGENTC_REQUEST_RSA_IDENTITIES:
/*
* Reply with SSH1_AGENT_RSA_IDENTITIES_ANSWER.
*/
{
int len;
void *keylist;
plog(logctx, logfn, "request: SSH1_AGENTC_REQUEST_RSA_IDENTITIES");
ret[4] = SSH1_AGENT_RSA_IDENTITIES_ANSWER;
keylist = pageant_make_keylist1(&len);
if (len + 5 > AGENT_MAX_MSGLEN) {
sfree(keylist);
fail_reason = "output would exceed max msglen";
goto failure;
}
PUT_32BIT(ret, len + 1);
memcpy(ret + 5, keylist, len);
plog(logctx, logfn, "reply: SSH1_AGENT_RSA_IDENTITIES_ANSWER");
if (logfn) { /* skip this loop if not logging */
int i;
struct RSAKey *rkey;
for (i = 0; NULL != (rkey = pageant_nth_ssh1_key(i)); i++) {
char fingerprint[128];
rsa_fingerprint(fingerprint, sizeof(fingerprint), rkey);
plog(logctx, logfn, "returned key: %s", fingerprint);
}
}
sfree(keylist);
}
break;
case SSH2_AGENTC_REQUEST_IDENTITIES:
/*
* Reply with SSH2_AGENT_IDENTITIES_ANSWER.
*/
{
int len;
void *keylist;
plog(logctx, logfn, "request: SSH2_AGENTC_REQUEST_IDENTITIES");
ret[4] = SSH2_AGENT_IDENTITIES_ANSWER;
keylist = pageant_make_keylist2(&len);
if (len + 5 > AGENT_MAX_MSGLEN) {
sfree(keylist);
fail_reason = "output would exceed max msglen";
goto failure;
}
PUT_32BIT(ret, len + 1);
memcpy(ret + 5, keylist, len);
plog(logctx, logfn, "reply: SSH2_AGENT_IDENTITIES_ANSWER");
if (logfn) { /* skip this loop if not logging */
int i;
struct ssh2_userkey *skey;
for (i = 0; NULL != (skey = pageant_nth_ssh2_key(i)); i++) {
char *fingerprint = skey->alg->fingerprint(skey->data);
plog(logctx, logfn, "returned key: %s %s",
fingerprint, skey->comment);
sfree(fingerprint);
}
}
sfree(keylist);
}
break;
case SSH1_AGENTC_RSA_CHALLENGE:
/*
* Reply with either SSH1_AGENT_RSA_RESPONSE or
* SSH_AGENT_FAILURE, depending on whether we have that key
* or not.
*/
{
struct RSAKey reqkey, *key;
Bignum challenge, response;
unsigned char response_source[48], response_md5[16];
struct MD5Context md5c;
int i, len;
plog(logctx, logfn, "request: SSH1_AGENTC_RSA_CHALLENGE");
p += 4;
i = ssh1_read_bignum(p, msgend - p, &reqkey.exponent);
if (i < 0) {
fail_reason = "request truncated before key exponent";
goto failure;
}
p += i;
i = ssh1_read_bignum(p, msgend - p, &reqkey.modulus);
if (i < 0) {
freebn(reqkey.exponent);
fail_reason = "request truncated before key modulus";
goto failure;
}
p += i;
i = ssh1_read_bignum(p, msgend - p, &challenge);
if (i < 0) {
freebn(reqkey.exponent);
freebn(reqkey.modulus);
fail_reason = "request truncated before challenge";
goto failure;
}
p += i;
if (msgend < p+16) {
freebn(reqkey.exponent);
freebn(reqkey.modulus);
freebn(challenge);
fail_reason = "request truncated before session id";
goto failure;
}
memcpy(response_source + 32, p, 16);
p += 16;
if (msgend < p+4) {
freebn(reqkey.exponent);
freebn(reqkey.modulus);
freebn(challenge);
fail_reason = "request truncated before response type";
goto failure;
}
if (GET_32BIT(p) != 1) {
freebn(reqkey.exponent);
freebn(reqkey.modulus);
freebn(challenge);
fail_reason = "response type other than 1 not supported";
goto failure;
}
if (logfn) {
char fingerprint[128];
reqkey.comment = NULL;
rsa_fingerprint(fingerprint, sizeof(fingerprint), &reqkey);
plog(logctx, logfn, "requested key: %s", fingerprint);
}
if ((key = find234(rsakeys, &reqkey, NULL)) == NULL) {
freebn(reqkey.exponent);
freebn(reqkey.modulus);
freebn(challenge);
fail_reason = "key not found";
goto failure;
}
response = rsadecrypt(challenge, key);
for (i = 0; i < 32; i++)
response_source[i] = bignum_byte(response, 31 - i);
MD5Init(&md5c);
MD5Update(&md5c, response_source, 48);
MD5Final(response_md5, &md5c);
smemclr(response_source, 48); /* burn the evidence */
freebn(response); /* and that evidence */
freebn(challenge); /* yes, and that evidence */
freebn(reqkey.exponent); /* and free some memory ... */
freebn(reqkey.modulus); /* ... while we're at it. */
/*
* Packet is the obvious five byte header, plus sixteen
* bytes of MD5.
*/
len = 5 + 16;
PUT_32BIT(ret, len - 4);
ret[4] = SSH1_AGENT_RSA_RESPONSE;
memcpy(ret + 5, response_md5, 16);
plog(logctx, logfn, "reply: SSH1_AGENT_RSA_RESPONSE");
}
break;
case SSH2_AGENTC_SIGN_REQUEST:
/*
* Reply with either SSH2_AGENT_SIGN_RESPONSE or
* SSH_AGENT_FAILURE, depending on whether we have that key
* or not.
*/
{
struct ssh2_userkey *key;
struct blob b;
const unsigned char *data;
unsigned char *signature;
int datalen, siglen, len;
plog(logctx, logfn, "request: SSH2_AGENTC_SIGN_REQUEST");
if (msgend < p+4) {
fail_reason = "request truncated before public key";
goto failure;
}
b.len = toint(GET_32BIT(p));
if (b.len < 0 || b.len > msgend - (p+4)) {
fail_reason = "request truncated before public key";
goto failure;
}
p += 4;
b.blob = p;
p += b.len;
if (msgend < p+4) {
fail_reason = "request truncated before string to sign";
goto failure;
}
datalen = toint(GET_32BIT(p));
p += 4;
if (datalen < 0 || datalen > msgend - p) {
fail_reason = "request truncated before string to sign";
goto failure;
}
data = p;
if (logfn) {
char *fingerprint = fingerprint_ssh2_blob(b.blob, b.len);
plog(logctx, logfn, "requested key: %s", fingerprint);
sfree(fingerprint);
}
key = find234(ssh2keys, &b, cmpkeys_ssh2_asymm);
if (!key) {
fail_reason = "key not found";
goto failure;
}
signature = key->alg->sign(key->data, (const char *)data,
datalen, &siglen);
len = 5 + 4 + siglen;
PUT_32BIT(ret, len - 4);
ret[4] = SSH2_AGENT_SIGN_RESPONSE;
PUT_32BIT(ret + 5, siglen);
memcpy(ret + 5 + 4, signature, siglen);
sfree(signature);
plog(logctx, logfn, "reply: SSH2_AGENT_SIGN_RESPONSE");
}
break;
case SSH1_AGENTC_ADD_RSA_IDENTITY:
/*
* Add to the list and return SSH_AGENT_SUCCESS, or
* SSH_AGENT_FAILURE if the key was malformed.
*/
{
struct RSAKey *key;
char *comment;
int n, commentlen;
plog(logctx, logfn, "request: SSH1_AGENTC_ADD_RSA_IDENTITY");
key = snew(struct RSAKey);
memset(key, 0, sizeof(struct RSAKey));
n = makekey(p, msgend - p, key, NULL, 1);
if (n < 0) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before public key";
goto failure;
}
p += n;
n = makeprivate(p, msgend - p, key);
if (n < 0) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before private key";
goto failure;
}
p += n;
/* SSH-1 names p and q the other way round, i.e. we have
* the inverse of p mod q and not of q mod p. We swap the
* names, because our internal RSA wants iqmp. */
n = ssh1_read_bignum(p, msgend - p, &key->iqmp); /* p^-1 mod q */
if (n < 0) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before iqmp";
goto failure;
}
p += n;
n = ssh1_read_bignum(p, msgend - p, &key->q); /* p */
if (n < 0) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before p";
goto failure;
}
p += n;
n = ssh1_read_bignum(p, msgend - p, &key->p); /* q */
if (n < 0) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before q";
goto failure;
}
p += n;
if (msgend < p+4) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before key comment";
goto failure;
}
commentlen = toint(GET_32BIT(p));
if (commentlen < 0 || commentlen > msgend - p) {
freersakey(key);
sfree(key);
fail_reason = "request truncated before key comment";
goto failure;
}
comment = snewn(commentlen+1, char);
if (comment) {
memcpy(comment, p + 4, commentlen);
comment[commentlen] = '\0';
key->comment = comment;
}
if (logfn) {
char fingerprint[128];
rsa_fingerprint(fingerprint, sizeof(fingerprint), key);
plog(logctx, logfn, "submitted key: %s", fingerprint);
}
if (add234(rsakeys, key) == key) {
keylist_update();
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
} else {
freersakey(key);
sfree(key);
fail_reason = "key already present";
goto failure;
}
}
break;
case SSH2_AGENTC_ADD_IDENTITY:
/*
* Add to the list and return SSH_AGENT_SUCCESS, or
* SSH_AGENT_FAILURE if the key was malformed.
*/
{
struct ssh2_userkey *key;
char *comment;
const char *alg;
int alglen, commlen;
int bloblen;
plog(logctx, logfn, "request: SSH2_AGENTC_ADD_IDENTITY");
if (msgend < p+4) {
fail_reason = "request truncated before key algorithm";
goto failure;
}
alglen = toint(GET_32BIT(p));
p += 4;
if (alglen < 0 || alglen > msgend - p) {
fail_reason = "request truncated before key algorithm";
goto failure;
}
alg = (const char *)p;
p += alglen;
key = snew(struct ssh2_userkey);
key->alg = find_pubkey_alg_len(alglen, alg);
if (!key->alg) {
sfree(key);
fail_reason = "algorithm unknown";
goto failure;
}
bloblen = msgend - p;
key->data = key->alg->openssh_createkey(&p, &bloblen);
if (!key->data) {
sfree(key);
fail_reason = "key setup failed";
goto failure;
}
/*
* p has been advanced by openssh_createkey, but
* certainly not _beyond_ the end of the buffer.
*/
assert(p <= msgend);
if (msgend < p+4) {
key->alg->freekey(key->data);
sfree(key);
fail_reason = "request truncated before key comment";
goto failure;
}
commlen = toint(GET_32BIT(p));
p += 4;
if (commlen < 0 || commlen > msgend - p) {
key->alg->freekey(key->data);
sfree(key);
fail_reason = "request truncated before key comment";
goto failure;
}
comment = snewn(commlen + 1, char);
if (comment) {
memcpy(comment, p, commlen);
comment[commlen] = '\0';
}
key->comment = comment;
if (logfn) {
char *fingerprint = key->alg->fingerprint(key->data);
plog(logctx, logfn, "submitted key: %s %s",
fingerprint, key->comment);
sfree(fingerprint);
}
if (add234(ssh2keys, key) == key) {
keylist_update();
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
} else {
key->alg->freekey(key->data);
sfree(key->comment);
sfree(key);
fail_reason = "key already present";
goto failure;
}
}
break;
case SSH1_AGENTC_REMOVE_RSA_IDENTITY:
/*
* Remove from the list and return SSH_AGENT_SUCCESS, or
* perhaps SSH_AGENT_FAILURE if it wasn't in the list to
* start with.
*/
{
struct RSAKey reqkey, *key;
int n;
plog(logctx, logfn, "request: SSH1_AGENTC_REMOVE_RSA_IDENTITY");
n = makekey(p, msgend - p, &reqkey, NULL, 0);
if (n < 0) {
fail_reason = "request truncated before public key";
goto failure;
}
if (logfn) {
char fingerprint[128];
reqkey.comment = NULL;
rsa_fingerprint(fingerprint, sizeof(fingerprint), &reqkey);
plog(logctx, logfn, "unwanted key: %s", fingerprint);
}
key = find234(rsakeys, &reqkey, NULL);
freebn(reqkey.exponent);
freebn(reqkey.modulus);
PUT_32BIT(ret, 1);
if (key) {
plog(logctx, logfn, "found with comment: %s", key->comment);
del234(rsakeys, key);
keylist_update();
freersakey(key);
sfree(key);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
} else {
fail_reason = "key not found";
goto failure;
}
}
break;
case SSH2_AGENTC_REMOVE_IDENTITY:
/*
* Remove from the list and return SSH_AGENT_SUCCESS, or
* perhaps SSH_AGENT_FAILURE if it wasn't in the list to
* start with.
*/
{
struct ssh2_userkey *key;
struct blob b;
plog(logctx, logfn, "request: SSH2_AGENTC_REMOVE_IDENTITY");
if (msgend < p+4) {
fail_reason = "request truncated before public key";
goto failure;
}
b.len = toint(GET_32BIT(p));
p += 4;
if (b.len < 0 || b.len > msgend - p) {
fail_reason = "request truncated before public key";
goto failure;
}
b.blob = p;
p += b.len;
if (logfn) {
char *fingerprint = fingerprint_ssh2_blob(b.blob, b.len);
plog(logctx, logfn, "unwanted key: %s", fingerprint);
sfree(fingerprint);
}
key = find234(ssh2keys, &b, cmpkeys_ssh2_asymm);
if (!key) {
fail_reason = "key not found";
goto failure;
}
plog(logctx, logfn, "found with comment: %s", key->comment);
del234(ssh2keys, key);
keylist_update();
key->alg->freekey(key->data);
sfree(key);
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
}
break;
case SSH1_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
/*
* Remove all SSH-1 keys. Always returns success.
*/
{
struct RSAKey *rkey;
plog(logctx, logfn, "request:"
" SSH1_AGENTC_REMOVE_ALL_RSA_IDENTITIES");
while ((rkey = index234(rsakeys, 0)) != NULL) {
del234(rsakeys, rkey);
freersakey(rkey);
sfree(rkey);
}
keylist_update();
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
}
break;
case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
/*
* Remove all SSH-2 keys. Always returns success.
*/
{
struct ssh2_userkey *skey;
plog(logctx, logfn, "request: SSH2_AGENTC_REMOVE_ALL_IDENTITIES");
while ((skey = index234(ssh2keys, 0)) != NULL) {
del234(ssh2keys, skey);
skey->alg->freekey(skey->data);
sfree(skey);
}
keylist_update();
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_SUCCESS;
plog(logctx, logfn, "reply: SSH_AGENT_SUCCESS");
}
break;
default:
plog(logctx, logfn, "request: unknown message type %d", type);
fail_reason = "unrecognised message";
/* fall through */
failure:
/*
* Unrecognised message. Return SSH_AGENT_FAILURE.
*/
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_FAILURE;
plog(logctx, logfn, "reply: SSH_AGENT_FAILURE (%s)", fail_reason);
break;
}
*outlen = 4 + GET_32BIT(ret);
return ret;
}
void *pageant_failure_msg(int *outlen)
{
unsigned char *ret = snewn(5, unsigned char);
PUT_32BIT(ret, 1);
ret[4] = SSH_AGENT_FAILURE;
*outlen = 5;
return ret;
}
void pageant_init(void)
{
pageant_local = TRUE;
rsakeys = newtree234(cmpkeys_rsa);
ssh2keys = newtree234(cmpkeys_ssh2);
}
struct RSAKey *pageant_nth_ssh1_key(int i)
{
return index234(rsakeys, i);
}
struct ssh2_userkey *pageant_nth_ssh2_key(int i)
{
return index234(ssh2keys, i);
}
int pageant_count_ssh1_keys(void)
{
return count234(rsakeys);
}
int pageant_count_ssh2_keys(void)
{
return count234(ssh2keys);
}
int pageant_add_ssh1_key(struct RSAKey *rkey)
{
return add234(rsakeys, rkey) == rkey;
}
int pageant_add_ssh2_key(struct ssh2_userkey *skey)
{
return add234(ssh2keys, skey) == skey;
}
int pageant_delete_ssh1_key(struct RSAKey *rkey)
{
struct RSAKey *deleted = del234(rsakeys, rkey);
if (!deleted)
return FALSE;
assert(deleted == rkey);
return TRUE;
}
int pageant_delete_ssh2_key(struct ssh2_userkey *skey)
{
struct ssh2_userkey *deleted = del234(ssh2keys, skey);
if (!deleted)
return FALSE;
assert(deleted == skey);
return TRUE;
}
/* ----------------------------------------------------------------------
* The agent plug.
*/
/*
* Coroutine macros similar to, but simplified from, those in ssh.c.
*/
#define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
#define crFinish(z) } *crLine = 0; return (z); }
#define crGetChar(c) do \
{ \
while (len == 0) { \
*crLine =__LINE__; return 1; case __LINE__:; \
} \
len--; \
(c) = (unsigned char)*data++; \
} while (0)
struct pageant_conn_state {
const struct plug_function_table *fn;
/* the above variable absolutely *must* be the first in this structure */
Socket connsock;
void *logctx;
pageant_logfn_t logfn;
unsigned char lenbuf[4], pktbuf[AGENT_MAX_MSGLEN];
unsigned len, got;
int real_packet;
int crLine; /* for coroutine in pageant_conn_receive */
};
static int pageant_conn_closing(Plug plug, const char *error_msg,
int error_code, int calling_back)
{
struct pageant_conn_state *pc = (struct pageant_conn_state *)plug;
if (error_msg)
plog(pc->logctx, pc->logfn, "%p: error: %s", pc, error_msg);
else
plog(pc->logctx, pc->logfn, "%p: connection closed", pc);
sk_close(pc->connsock);
sfree(pc);
return 1;
}
static void pageant_conn_sent(Plug plug, int bufsize)
{
/* struct pageant_conn_state *pc = (struct pageant_conn_state *)plug; */
/*
* We do nothing here, because we expect that there won't be a
* need to throttle and unthrottle the connection to an agent -
* clients will typically not send many requests, and will wait
* until they receive each reply before sending a new request.
*/
}
static void pageant_conn_log(void *logctx, const char *fmt, va_list ap)
{
/* Wrapper on pc->logfn that prefixes the connection identifier */
struct pageant_conn_state *pc = (struct pageant_conn_state *)logctx;
char *formatted = dupvprintf(fmt, ap);
plog(pc->logctx, pc->logfn, "%p: %s", pc, formatted);
sfree(formatted);
}
static int pageant_conn_receive(Plug plug, int urgent, char *data, int len)
{
struct pageant_conn_state *pc = (struct pageant_conn_state *)plug;
char c;
crBegin(pc->crLine);
while (len > 0) {
pc->got = 0;
while (pc->got < 4) {
crGetChar(c);
pc->lenbuf[pc->got++] = c;
}
pc->len = GET_32BIT(pc->lenbuf);
pc->got = 0;
pc->real_packet = (pc->len < AGENT_MAX_MSGLEN-4);
while (pc->got < pc->len) {
crGetChar(c);
if (pc->real_packet)
pc->pktbuf[pc->got] = c;
pc->got++;
}
{
void *reply;
int replylen;
if (pc->real_packet) {
reply = pageant_handle_msg(pc->pktbuf, pc->len, &replylen, pc,
pc->logfn?pageant_conn_log:NULL);
} else {
plog(pc->logctx, pc->logfn, "%p: overlong message (%u)",
pc, pc->len);
plog(pc->logctx, pc->logfn, "%p: reply: SSH_AGENT_FAILURE "
"(message too long)", pc);
reply = pageant_failure_msg(&replylen);
}
sk_write(pc->connsock, reply, replylen);
smemclr(reply, replylen);
}
}
crFinish(1);
}
struct pageant_listen_state {
const struct plug_function_table *fn;
/* the above variable absolutely *must* be the first in this structure */
Socket listensock;
void *logctx;
pageant_logfn_t logfn;
};
static int pageant_listen_closing(Plug plug, const char *error_msg,
int error_code, int calling_back)
{
struct pageant_listen_state *pl = (struct pageant_listen_state *)plug;
if (error_msg)
plog(pl->logctx, pl->logfn, "listening socket: error: %s", error_msg);
sk_close(pl->listensock);
pl->listensock = NULL;
return 1;
}
static int pageant_listen_accepting(Plug plug,
accept_fn_t constructor, accept_ctx_t ctx)
{
static const struct plug_function_table connection_fn_table = {
NULL, /* no log function, because that's for outgoing connections */
pageant_conn_closing,
pageant_conn_receive,
pageant_conn_sent,
NULL /* no accepting function, because we've already done it */
};
struct pageant_listen_state *pl = (struct pageant_listen_state *)plug;
struct pageant_conn_state *pc;
const char *err;
pc = snew(struct pageant_conn_state);
pc->fn = &connection_fn_table;
pc->logfn = pl->logfn;
pc->logctx = pl->logctx;
pc->crLine = 0;
pc->connsock = constructor(ctx, (Plug) pc);
if ((err = sk_socket_error(pc->connsock)) != NULL) {
sk_close(pc->connsock);
sfree(pc);
return TRUE;
}
sk_set_frozen(pc->connsock, 0);
/* FIXME: can we get any useful peer id info? */
plog(pl->logctx, pl->logfn, "%p: new connection", pc);
return 0;
}
struct pageant_listen_state *pageant_listener_new(void)
{
static const struct plug_function_table listener_fn_table = {
NULL, /* no log function, because that's for outgoing connections */
pageant_listen_closing,
NULL, /* no receive function on a listening socket */
NULL, /* no sent function on a listening socket */
pageant_listen_accepting
};
struct pageant_listen_state *pl = snew(struct pageant_listen_state);
pl->fn = &listener_fn_table;
pl->logctx = NULL;
pl->logfn = NULL;
pl->listensock = NULL;
return pl;
}
void pageant_listener_got_socket(struct pageant_listen_state *pl, Socket sock)
{
pl->listensock = sock;
}
void pageant_listener_set_logfn(struct pageant_listen_state *pl,
void *logctx, pageant_logfn_t logfn)
{
pl->logctx = logctx;
pl->logfn = logfn;
}
void pageant_listener_free(struct pageant_listen_state *pl)
{
if (pl->listensock)
sk_close(pl->listensock);
sfree(pl);
}
/* ----------------------------------------------------------------------
* Code to perform agent operations either as a client, or within the
* same process as the running agent.
*/
static tree234 *passphrases = NULL;
/*
* After processing a list of filenames, we want to forget the
* passphrases.
*/
void pageant_forget_passphrases(void)
{
while (count234(passphrases) > 0) {
char *pp = index234(passphrases, 0);
smemclr(pp, strlen(pp));
delpos234(passphrases, 0);
free(pp);
}
}
void *pageant_get_keylist1(int *length)
{
void *ret;
if (!pageant_local) {
unsigned char request[5], *response;
void *vresponse;
int resplen, retval;
request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
PUT_32BIT(request, 1);
retval = agent_query(request, 5, &vresponse, &resplen, NULL, NULL);
assert(retval == 1);
response = vresponse;
if (resplen < 5 || response[4] != SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
sfree(response);
return NULL;
}
ret = snewn(resplen-5, unsigned char);
memcpy(ret, response+5, resplen-5);
sfree(response);
if (length)
*length = resplen-5;
} else {
ret = pageant_make_keylist1(length);
}
return ret;
}
void *pageant_get_keylist2(int *length)
{
void *ret;
if (!pageant_local) {
unsigned char request[5], *response;
void *vresponse;
int resplen, retval;
request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
PUT_32BIT(request, 1);
retval = agent_query(request, 5, &vresponse, &resplen, NULL, NULL);
assert(retval == 1);
response = vresponse;
if (resplen < 5 || response[4] != SSH2_AGENT_IDENTITIES_ANSWER) {
sfree(response);
return NULL;
}
ret = snewn(resplen-5, unsigned char);
memcpy(ret, response+5, resplen-5);
sfree(response);
if (length)
*length = resplen-5;
} else {
ret = pageant_make_keylist2(length);
}
return ret;
}
int pageant_add_keyfile(Filename *filename, const char *passphrase,
char **retstr)
{
struct RSAKey *rkey = NULL;
struct ssh2_userkey *skey = NULL;
int needs_pass;
int ret;
int attempts;
char *comment;
const char *this_passphrase;
const char *error = NULL;
int type;
if (!passphrases) {
passphrases = newtree234(NULL);
}
*retstr = NULL;
type = key_type(filename);
if (type != SSH_KEYTYPE_SSH1 && type != SSH_KEYTYPE_SSH2) {
*retstr = dupprintf("Couldn't load this key (%s)",
key_type_to_str(type));
return PAGEANT_ACTION_FAILURE;
}
/*
* See if the key is already loaded (in the primary Pageant,
* which may or may not be us).
*/
{
void *blob;
unsigned char *keylist, *p;
int i, nkeys, bloblen, keylistlen;
if (type == SSH_KEYTYPE_SSH1) {
if (!rsakey_pubblob(filename, &blob, &bloblen, NULL, &error)) {
*retstr = dupprintf("Couldn't load private key (%s)", error);
return PAGEANT_ACTION_FAILURE;
}
keylist = pageant_get_keylist1(&keylistlen);
} else {
unsigned char *blob2;
blob = ssh2_userkey_loadpub(filename, NULL, &bloblen,
NULL, &error);
if (!blob) {
*retstr = dupprintf("Couldn't load private key (%s)", error);
return PAGEANT_ACTION_FAILURE;
}
/* For our purposes we want the blob prefixed with its length */
blob2 = snewn(bloblen+4, unsigned char);
PUT_32BIT(blob2, bloblen);
memcpy(blob2 + 4, blob, bloblen);
sfree(blob);
blob = blob2;
keylist = pageant_get_keylist2(&keylistlen);
}
if (keylist) {
if (keylistlen < 4) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
nkeys = toint(GET_32BIT(keylist));
if (nkeys < 0) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
p = keylist + 4;
keylistlen -= 4;
for (i = 0; i < nkeys; i++) {
if (!memcmp(blob, p, bloblen)) {
/* Key is already present; we can now leave. */
sfree(keylist);
sfree(blob);
return PAGEANT_ACTION_OK;
}
/* Now skip over public blob */
if (type == SSH_KEYTYPE_SSH1) {
int n = rsa_public_blob_len(p, keylistlen);
if (n < 0) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
p += n;
keylistlen -= n;
} else {
int n;
if (keylistlen < 4) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
n = toint(4 + GET_32BIT(p));
if (n < 0 || keylistlen < n) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
p += n;
keylistlen -= n;
}
/* Now skip over comment field */
{
int n;
if (keylistlen < 4) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
n = toint(4 + GET_32BIT(p));
if (n < 0 || keylistlen < n) {
*retstr = dupstr("Received broken key list from agent");
return PAGEANT_ACTION_FAILURE;
}
p += n;
keylistlen -= n;
}
}
sfree(keylist);
}
sfree(blob);
}
error = NULL;
if (type == SSH_KEYTYPE_SSH1)
needs_pass = rsakey_encrypted(filename, &comment);
else
needs_pass = ssh2_userkey_encrypted(filename, &comment);
attempts = 0;
if (type == SSH_KEYTYPE_SSH1)
rkey = snew(struct RSAKey);
/*
* Loop round repeatedly trying to load the key, until we either
* succeed, fail for some serious reason, or run out of
* passphrases to try.
*/
while (1) {
if (needs_pass) {
/*
* If we've been given a passphrase on input, try using
* it. Otherwise, try one from our tree234 of previously
* useful passphrases.
*/
if (passphrase) {
this_passphrase = (attempts == 0 ? passphrase : NULL);
} else {
this_passphrase = (const char *)index234(passphrases, attempts);
}
if (!this_passphrase) {
/*
* Run out of passphrases to try.
*/
*retstr = comment;
return PAGEANT_ACTION_NEED_PP;
}
} else
this_passphrase = "";
if (type == SSH_KEYTYPE_SSH1)
ret = loadrsakey(filename, rkey, this_passphrase, &error);
else {
skey = ssh2_load_userkey(filename, this_passphrase, &error);
if (skey == SSH2_WRONG_PASSPHRASE)
ret = -1;
else if (!skey)
ret = 0;
else
ret = 1;
}
if (ret == 0) {
/*
* Failed to load the key file, for some reason other than
* a bad passphrase.
*/
*retstr = dupstr(error);
return PAGEANT_ACTION_FAILURE;
} else if (ret == 1) {
/*
* Successfully loaded the key file.
*/
break;
} else {
/*
* Passphrase wasn't right; go round again.
*/
attempts++;
}
}
/*
* If we get here, we've succesfully loaded the key into
* rkey/skey, but not yet added it to the agent.
*/
/*
* If the key was successfully decrypted, save the passphrase for
* use with other keys we try to load.
*/
{
char *pp_copy = dupstr(this_passphrase);
if (addpos234(passphrases, pp_copy, 0) != pp_copy) {
/* No need; it was already there. */
smemclr(pp_copy, strlen(pp_copy));
sfree(pp_copy);
}
}
if (comment)
sfree(comment);
if (type == SSH_KEYTYPE_SSH1) {
if (!pageant_local) {
unsigned char *request, *response;
void *vresponse;
int reqlen, clen, resplen, ret;
clen = strlen(rkey->comment);
reqlen = 4 + 1 + /* length, message type */
4 + /* bit count */
ssh1_bignum_length(rkey->modulus) +
ssh1_bignum_length(rkey->exponent) +
ssh1_bignum_length(rkey->private_exponent) +
ssh1_bignum_length(rkey->iqmp) +
ssh1_bignum_length(rkey->p) +
ssh1_bignum_length(rkey->q) + 4 + clen /* comment */
;
request = snewn(reqlen, unsigned char);
request[4] = SSH1_AGENTC_ADD_RSA_IDENTITY;
reqlen = 5;
PUT_32BIT(request + reqlen, bignum_bitcount(rkey->modulus));
reqlen += 4;
reqlen += ssh1_write_bignum(request + reqlen, rkey->modulus);
reqlen += ssh1_write_bignum(request + reqlen, rkey->exponent);
reqlen +=
ssh1_write_bignum(request + reqlen,
rkey->private_exponent);
reqlen += ssh1_write_bignum(request + reqlen, rkey->iqmp);
reqlen += ssh1_write_bignum(request + reqlen, rkey->p);
reqlen += ssh1_write_bignum(request + reqlen, rkey->q);
PUT_32BIT(request + reqlen, clen);
memcpy(request + reqlen + 4, rkey->comment, clen);
reqlen += 4 + clen;
PUT_32BIT(request, reqlen - 4);
ret = agent_query(request, reqlen, &vresponse, &resplen,
NULL, NULL);
assert(ret == 1);
response = vresponse;
if (resplen < 5 || response[4] != SSH_AGENT_SUCCESS) {
*retstr = dupstr("The already running Pageant "
"refused to add the key.");
return PAGEANT_ACTION_FAILURE;
}
sfree(request);
sfree(response);
} else {
if (!pageant_add_ssh1_key(rkey)) {
sfree(rkey); /* already present, don't waste RAM */
}
}
} else {
if (!pageant_local) {
unsigned char *request, *response;
void *vresponse;
int reqlen, alglen, clen, keybloblen, resplen, ret;
alglen = strlen(skey->alg->name);
clen = strlen(skey->comment);
keybloblen = skey->alg->openssh_fmtkey(skey->data, NULL, 0);
reqlen = 4 + 1 + /* length, message type */
4 + alglen + /* algorithm name */
keybloblen + /* key data */
4 + clen /* comment */
;
request = snewn(reqlen, unsigned char);
request[4] = SSH2_AGENTC_ADD_IDENTITY;
reqlen = 5;
PUT_32BIT(request + reqlen, alglen);
reqlen += 4;
memcpy(request + reqlen, skey->alg->name, alglen);
reqlen += alglen;
reqlen += skey->alg->openssh_fmtkey(skey->data,
request + reqlen,
keybloblen);
PUT_32BIT(request + reqlen, clen);
memcpy(request + reqlen + 4, skey->comment, clen);
reqlen += clen + 4;
PUT_32BIT(request, reqlen - 4);
ret = agent_query(request, reqlen, &vresponse, &resplen,
NULL, NULL);
assert(ret == 1);
response = vresponse;
if (resplen < 5 || response[4] != SSH_AGENT_SUCCESS) {
*retstr = dupstr("The already running Pageant "
"refused to add the key.");
return PAGEANT_ACTION_FAILURE;
}
sfree(request);
sfree(response);
} else {
if (!pageant_add_ssh2_key(skey)) {
skey->alg->freekey(skey->data);
sfree(skey); /* already present, don't waste RAM */
}
}
}
return PAGEANT_ACTION_OK;
}
int pageant_enum_keys(pageant_key_enum_fn_t callback, void *callback_ctx,
char **retstr)
{
unsigned char *keylist, *p;
int i, nkeys, keylistlen;
char *comment;
keylist = pageant_get_keylist1(&keylistlen);
if (keylistlen < 4) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
nkeys = toint(GET_32BIT(keylist));
if (nkeys < 0) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
p = keylist + 4;
keylistlen -= 4;
for (i = 0; i < nkeys; i++) {
struct RSAKey rkey;
char fingerprint[128];
int n;
/* public blob and fingerprint */
memset(&rkey, 0, sizeof(rkey));
n = makekey(p, keylistlen, &rkey, NULL, 0);
if (n < 0 || n > keylistlen) {
freersakey(&rkey);
*retstr = dupstr("Received broken SSH-1 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
p += n, keylistlen -= n;
rsa_fingerprint(fingerprint, sizeof(fingerprint), &rkey);
/* comment */
if (keylistlen < 4) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
freersakey(&rkey);
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
n = toint(GET_32BIT(p));
p += 4, keylistlen -= 4;
if (n < 0 || keylistlen < n) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
freersakey(&rkey);
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
comment = dupprintf("%.*s", (int)n, (const char *)p);
p += n, keylistlen -= n;
callback(callback_ctx, fingerprint, comment);
freersakey(&rkey);
sfree(comment);
}
sfree(keylist);
if (keylistlen != 0) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
return PAGEANT_ACTION_FAILURE;
}
keylist = pageant_get_keylist2(&keylistlen);
if (keylistlen < 4) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
nkeys = toint(GET_32BIT(keylist));
if (nkeys < 0) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
p = keylist + 4;
keylistlen -= 4;
for (i = 0; i < nkeys; i++) {
char *fingerprint;
int n;
/* public blob */
if (keylistlen < 4) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
n = toint(GET_32BIT(p));
p += 4, keylistlen -= 4;
if (n < 0 || keylistlen < n) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
fingerprint = fingerprint_ssh2_blob(p, n);
p += n, keylistlen -= n;
/* comment */
if (keylistlen < 4) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(fingerprint);
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
n = toint(GET_32BIT(p));
p += 4, keylistlen -= 4;
if (n < 0 || keylistlen < n) {
*retstr = dupstr("Received broken SSH-2 key list from agent");
sfree(fingerprint);
sfree(keylist);
return PAGEANT_ACTION_FAILURE;
}
comment = dupprintf("%.*s", (int)n, (const char *)p);
p += n, keylistlen -= n;
callback(callback_ctx, fingerprint, comment);
sfree(fingerprint);
sfree(comment);
}
sfree(keylist);
if (keylistlen != 0) {
*retstr = dupstr("Received broken SSH-1 key list from agent");
return PAGEANT_ACTION_FAILURE;
}
return PAGEANT_ACTION_OK;
}
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