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Pageant server: parse requests using BinarySource.
pageant_handle_msg was _particularly_ full of painful manual packet decoding with error checks at every stage, so it's a great relief to throw it all away and replace it with short sequences of calls to the shiny new API!
This commit is contained in:
Simon Tatham
parent
e43605ee05
commit
392a8c00f6
335
pageant.c
335
pageant.c
@ -80,7 +80,7 @@ static int cmpkeys_rsa(void *av, void *bv)
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*/
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static int cmpkeys_ssh2_asymm(void *av, void *bv)
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{
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strbuf *ablob = (strbuf *) av;
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ptrlen *ablob = (ptrlen *) av;
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struct ssh2_userkey *b = (struct ssh2_userkey *) bv;
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strbuf *bblob;
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int i, c;
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@ -93,10 +93,11 @@ static int cmpkeys_ssh2_asymm(void *av, void *bv)
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c = 0;
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for (i = 0; i < ablob->len && i < bblob->len; i++) {
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if (ablob->u[i] < bblob->u[i]) {
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unsigned char abyte = ((unsigned char *)ablob->ptr)[i];
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if (abyte < bblob->u[i]) {
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c = -1;
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break;
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} else if (ablob->u[i] > bblob->u[i]) {
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} else if (abyte > bblob->u[i]) {
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c = +1;
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break;
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}
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@ -118,11 +119,14 @@ static int cmpkeys_ssh2(void *av, void *bv)
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{
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struct ssh2_userkey *a = (struct ssh2_userkey *) av;
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strbuf *ablob;
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ptrlen apl;
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int toret;
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ablob = strbuf_new();
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a->alg->public_blob(a->data, BinarySink_UPCAST(ablob));
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toret = cmpkeys_ssh2_asymm(ablob, bv);
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apl.ptr = ablob->u;
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apl.len = ablob->len;
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toret = cmpkeys_ssh2_asymm(&apl, bv);
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strbuf_free(ablob);
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return toret;
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}
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@ -178,24 +182,20 @@ static void plog(void *logctx, pageant_logfn_t logfn, const char *fmt, ...)
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}
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void pageant_handle_msg(BinarySink *bs,
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const void *msg, int msglen,
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const void *msgdata, int msglen,
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void *logctx, pageant_logfn_t logfn)
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{
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const unsigned char *p = msg;
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const unsigned char *msgend;
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BinarySource msg[1];
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int type;
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msgend = p + msglen;
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BinarySource_BARE_INIT(msg, msgdata, msglen);
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/*
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* Get the message type.
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*/
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if (msgend < p+1) {
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type = get_byte(msg);
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if (get_err(msg)) {
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pageant_failure_msg(bs, "message contained no type code",
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logctx, logfn);
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return;
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}
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type = *p++;
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switch (type) {
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case SSH1_AGENTC_REQUEST_RSA_IDENTITIES:
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@ -253,59 +253,34 @@ void pageant_handle_msg(BinarySink *bs,
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{
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struct RSAKey reqkey, *key;
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Bignum challenge, response;
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unsigned char response_source[48], response_md5[16];
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ptrlen session_id;
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unsigned response_type;
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unsigned char response_md5[16];
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struct MD5Context md5c;
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int i;
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plog(logctx, logfn, "request: SSH1_AGENTC_RSA_CHALLENGE");
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reqkey.exponent = reqkey.modulus = challenge = response = NULL;
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response = NULL;
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memset(&reqkey, 0, sizeof(reqkey));
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p += 4;
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i = ssh1_read_bignum(p, msgend - p, &reqkey.exponent);
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if (i < 0) {
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pageant_failure_msg(
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bs, "request truncated before key exponent",
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logctx, logfn);
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get_rsa_ssh1_pub(msg, &reqkey, NULL, RSA_SSH1_EXPONENT_FIRST);
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challenge = get_mp_ssh1(msg);
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session_id = get_data(msg, 16);
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response_type = get_uint32(msg);
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if (get_err(msg)) {
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pageant_failure_msg(bs, "unable to decode request",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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p += i;
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i = ssh1_read_bignum(p, msgend - p, &reqkey.modulus);
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if (i < 0) {
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pageant_failure_msg(
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bs, "request truncated before key modulus",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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p += i;
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i = ssh1_read_bignum(p, msgend - p, &challenge);
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if (i < 0) {
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pageant_failure_msg(
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bs, "request truncated before challenge",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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p += i;
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if (msgend < p+16) {
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pageant_failure_msg(
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bs, "request truncated before session id",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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memcpy(response_source + 32, p, 16);
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p += 16;
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before response type",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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if (GET_32BIT(p) != 1) {
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if (response_type != 1) {
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pageant_failure_msg(
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bs, "response type other than 1 not supported",
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logctx, logfn);
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goto challenge1_cleanup;
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}
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if (logfn) {
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char fingerprint[128];
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reqkey.comment = NULL;
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@ -317,13 +292,12 @@ void pageant_handle_msg(BinarySink *bs,
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goto challenge1_cleanup;
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}
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response = rsa_ssh1_decrypt(challenge, key);
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for (i = 0; i < 32; i++)
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response_source[i] = bignum_byte(response, 31 - i);
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MD5Init(&md5c);
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put_data(&md5c, response_source, 48);
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for (i = 0; i < 32; i++)
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put_byte(&md5c, bignum_byte(response, 31 - i));
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put_data(&md5c, session_id.ptr, session_id.len);
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MD5Final(response_md5, &md5c);
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smemclr(response_source, 48); /* burn the evidence */
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put_byte(bs, SSH1_AGENT_RSA_RESPONSE);
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put_data(bs, response_md5, 16);
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@ -331,10 +305,11 @@ void pageant_handle_msg(BinarySink *bs,
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plog(logctx, logfn, "reply: SSH1_AGENT_RSA_RESPONSE");
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challenge1_cleanup:
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if (response) freebn(response);
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if (challenge) freebn(challenge);
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if (reqkey.exponent) freebn(reqkey.exponent);
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if (reqkey.modulus) freebn(reqkey.modulus);
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if (response)
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freebn(response);
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freebn(challenge);
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freebn(reqkey.exponent);
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freebn(reqkey.modulus);
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}
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break;
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case SSH2_AGENTC_SIGN_REQUEST:
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@ -345,56 +320,20 @@ void pageant_handle_msg(BinarySink *bs,
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*/
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{
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struct ssh2_userkey *key;
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const void *blobp;
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int bloblen;
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const unsigned char *data;
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ptrlen keyblob, sigdata;
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strbuf *signature;
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int datalen;
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plog(logctx, logfn, "request: SSH2_AGENTC_SIGN_REQUEST");
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before public key",
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logctx, logfn);
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return;
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}
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bloblen = toint(GET_32BIT(p));
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if (bloblen < 0 || bloblen > msgend - (p+4)) {
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pageant_failure_msg(
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bs, "request truncated before public key",
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logctx, logfn);
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return;
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}
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p += 4;
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blobp = p;
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p += bloblen;
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before string to sign",
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logctx, logfn);
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return;
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}
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datalen = toint(GET_32BIT(p));
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p += 4;
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if (datalen < 0 || datalen > msgend - p) {
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pageant_failure_msg(
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bs, "request truncated before string to sign",
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logctx, logfn);
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return;
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}
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data = p;
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keyblob = get_string(msg);
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sigdata = get_string(msg);
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if (logfn) {
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char *fingerprint = ssh2_fingerprint_blob(blobp, bloblen);
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char *fingerprint = ssh2_fingerprint_blob(
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keyblob.ptr, keyblob.len);
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plog(logctx, logfn, "requested key: %s", fingerprint);
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sfree(fingerprint);
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}
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{
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strbuf *blob = strbuf_new();
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put_data(blob, blobp, bloblen);
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key = find234(ssh2keys, blob, cmpkeys_ssh2_asymm);
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strbuf_free(blob);
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}
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key = find234(ssh2keys, &keyblob, cmpkeys_ssh2_asymm);
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if (!key) {
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pageant_failure_msg(bs, "key not found", logctx, logfn);
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return;
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@ -403,7 +342,7 @@ void pageant_handle_msg(BinarySink *bs,
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put_byte(bs, SSH2_AGENT_SIGN_RESPONSE);
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signature = strbuf_new();
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key->alg->sign(key->data, data, datalen,
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key->alg->sign(key->data, sigdata.ptr, sigdata.len,
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BinarySink_UPCAST(signature));
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put_stringsb(bs, signature);
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@ -417,88 +356,35 @@ void pageant_handle_msg(BinarySink *bs,
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*/
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{
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struct RSAKey *key;
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char *comment;
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int n, commentlen;
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plog(logctx, logfn, "request: SSH1_AGENTC_ADD_RSA_IDENTITY");
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key = snew(struct RSAKey);
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memset(key, 0, sizeof(struct RSAKey));
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n = rsa_ssh1_readpub(p, msgend - p, key, NULL,
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RSA_SSH1_MODULUS_FIRST);
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if (n < 0) {
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pageant_failure_msg(
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bs, "request truncated before public key",
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logctx, logfn);
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goto add1_cleanup;
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}
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p += n;
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n = rsa_ssh1_readpriv(p, msgend - p, key);
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if (n < 0) {
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pageant_failure_msg(
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bs, "request truncated before private key",
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logctx, logfn);
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goto add1_cleanup;
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}
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p += n;
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get_rsa_ssh1_pub(msg, key, NULL, RSA_SSH1_MODULUS_FIRST);
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get_rsa_ssh1_priv(msg, key);
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/* SSH-1 names p and q the other way round, i.e. we have
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* the inverse of p mod q and not of q mod p. We swap the
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* names, because our internal RSA wants iqmp. */
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key->iqmp = get_mp_ssh1(msg);
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key->q = get_mp_ssh1(msg);
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key->p = get_mp_ssh1(msg);
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n = ssh1_read_bignum(p, msgend - p, &key->iqmp); /* p^-1 mod q */
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if (n < 0) {
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pageant_failure_msg(bs, "request truncated before iqmp",
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key->comment = mkstr(get_string(msg));
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if (get_err(msg)) {
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pageant_failure_msg(bs, "unable to decode request",
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logctx, logfn);
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goto add1_cleanup;
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}
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p += n;
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n = ssh1_read_bignum(p, msgend - p, &key->q); /* p */
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if (n < 0) {
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pageant_failure_msg(bs, "request truncated before p",
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logctx, logfn);
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goto add1_cleanup;
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}
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p += n;
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n = ssh1_read_bignum(p, msgend - p, &key->p); /* q */
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if (n < 0) {
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pageant_failure_msg(
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bs, "request truncated before q", logctx, logfn);
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goto add1_cleanup;
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}
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p += n;
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before key comment",
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logctx, logfn);
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goto add1_cleanup;
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}
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commentlen = toint(GET_32BIT(p));
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if (commentlen < 0 || commentlen > msgend - p) {
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pageant_failure_msg(
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bs, "request truncated before key comment",
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logctx, logfn);
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goto add1_cleanup;
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}
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goto add1_cleanup;
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}
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if (!rsa_verify(key)) {
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pageant_failure_msg(bs, "key is invalid", logctx, logfn);
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goto add1_cleanup;
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}
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comment = snewn(commentlen+1, char);
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if (comment) {
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memcpy(comment, p + 4, commentlen);
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comment[commentlen] = '\0';
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key->comment = comment;
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}
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if (logfn) {
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char fingerprint[128];
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rsa_fingerprint(fingerprint, sizeof(fingerprint), key);
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@ -529,73 +415,42 @@ void pageant_handle_msg(BinarySink *bs,
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*/
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{
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struct ssh2_userkey *key = NULL;
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char *comment;
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const char *alg;
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int alglen, commlen;
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int bloblen;
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ptrlen alg;
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plog(logctx, logfn, "request: SSH2_AGENTC_ADD_IDENTITY");
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before key algorithm",
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logctx, logfn);
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goto add2_cleanup;
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}
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alglen = toint(GET_32BIT(p));
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p += 4;
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if (alglen < 0 || alglen > msgend - p) {
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pageant_failure_msg(
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bs, "request truncated before key algorithm",
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logctx, logfn);
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goto add2_cleanup;
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}
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alg = (const char *)p;
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p += alglen;
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alg = get_string(msg);
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key = snew(struct ssh2_userkey);
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key->data = NULL;
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key->comment = NULL;
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key->alg = find_pubkey_alg_len(make_ptrlen(alg, alglen));
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key->alg = find_pubkey_alg_len(alg);
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if (!key->alg) {
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pageant_failure_msg(bs, "algorithm unknown", logctx, logfn);
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goto add2_cleanup;
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}
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|
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bloblen = msgend - p;
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key->data = key->alg->openssh_createkey(key->alg, &p, &bloblen);
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{
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const unsigned char *p = get_ptr(msg);
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int len = get_avail(msg);
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key->data = key->alg->openssh_createkey(key->alg, &p, &len);
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assert(len >= 0);
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assert(len < get_avail(msg));
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msg->pos += get_avail(msg) - len;
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}
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if (!key->data) {
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pageant_failure_msg(bs, "key setup failed", logctx, logfn);
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goto add2_cleanup;
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}
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|
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/*
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* p has been advanced by openssh_createkey, but
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* certainly not _beyond_ the end of the buffer.
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*/
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assert(p <= msgend);
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key->comment = mkstr(get_string(msg));
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|
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if (msgend < p+4) {
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pageant_failure_msg(
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bs, "request truncated before key comment",
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logctx, logfn);
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goto add2_cleanup;
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}
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commlen = toint(GET_32BIT(p));
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p += 4;
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|
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if (commlen < 0 || commlen > msgend - p) {
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pageant_failure_msg(
|
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bs, "request truncated before key comment",
|
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logctx, logfn);
|
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goto add2_cleanup;
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}
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comment = snewn(commlen + 1, char);
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if (comment) {
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memcpy(comment, p, commlen);
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comment[commlen] = '\0';
|
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}
|
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key->comment = comment;
|
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if (get_err(msg)) {
|
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pageant_failure_msg(bs, "unable to decode request",
|
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logctx, logfn);
|
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goto add2_cleanup;
|
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}
|
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|
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if (logfn) {
|
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char *fingerprint = ssh2_fingerprint(key->alg, key->data);
|
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@ -634,17 +489,17 @@ void pageant_handle_msg(BinarySink *bs,
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*/
|
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{
|
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struct RSAKey reqkey, *key;
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int n;
|
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|
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plog(logctx, logfn, "request: SSH1_AGENTC_REMOVE_RSA_IDENTITY");
|
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|
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n = rsa_ssh1_readpub(p, msgend - p, &reqkey, NULL,
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RSA_SSH1_EXPONENT_FIRST);
|
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if (n < 0) {
|
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pageant_failure_msg(
|
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bs, "request truncated before public key",
|
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logctx, logfn);
|
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return;
|
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get_rsa_ssh1_pub(msg, &reqkey, NULL, RSA_SSH1_EXPONENT_FIRST);
|
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|
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if (get_err(msg)) {
|
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pageant_failure_msg(bs, "unable to decode request",
|
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logctx, logfn);
|
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freebn(reqkey.exponent);
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freebn(reqkey.modulus);
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||||
return;
|
||||
}
|
||||
|
||||
if (logfn) {
|
||||
@ -680,41 +535,25 @@ void pageant_handle_msg(BinarySink *bs,
|
||||
*/
|
||||
{
|
||||
struct ssh2_userkey *key;
|
||||
const void *blobp;
|
||||
int bloblen;
|
||||
ptrlen blob;
|
||||
|
||||
plog(logctx, logfn, "request: SSH2_AGENTC_REMOVE_IDENTITY");
|
||||
|
||||
if (msgend < p+4) {
|
||||
pageant_failure_msg(
|
||||
bs, "request truncated before public key",
|
||||
logctx, logfn);
|
||||
return;
|
||||
}
|
||||
bloblen = toint(GET_32BIT(p));
|
||||
p += 4;
|
||||
blob = get_string(msg);
|
||||
|
||||
if (bloblen < 0 || bloblen > msgend - p) {
|
||||
pageant_failure_msg(
|
||||
bs, "request truncated before public key",
|
||||
logctx, logfn);
|
||||
if (get_err(msg)) {
|
||||
pageant_failure_msg(bs, "unable to decode request",
|
||||
logctx, logfn);
|
||||
return;
|
||||
}
|
||||
blobp = p;
|
||||
p += bloblen;
|
||||
|
||||
if (logfn) {
|
||||
char *fingerprint = ssh2_fingerprint_blob(blobp, bloblen);
|
||||
char *fingerprint = ssh2_fingerprint_blob(blob.ptr, blob.len);
|
||||
plog(logctx, logfn, "unwanted key: %s", fingerprint);
|
||||
sfree(fingerprint);
|
||||
}
|
||||
|
||||
{
|
||||
strbuf *blob = strbuf_new();
|
||||
put_data(blob, blobp, bloblen);
|
||||
key = find234(ssh2keys, blob, cmpkeys_ssh2_asymm);
|
||||
strbuf_free(blob);
|
||||
}
|
||||
key = find234(ssh2keys, &blob, cmpkeys_ssh2_asymm);
|
||||
if (!key) {
|
||||
pageant_failure_msg(bs, "key not found", logctx, logfn);
|
||||
return;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user