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synced 2025-01-10 09:58:01 +00:00
Fix ssh2-cisco-pw-pad by reverting r5122. However, I've kept the
ability to easily re-enable the r5122 behaviour, in case we need to
conditionally switch between the two at a later date.
[originally from svn r7073]
[r5122 == 8a20515844]
[this svn revision also touched putty-wishlist]
This commit is contained in:
Simon Tatham
parent
720693cfab
commit
274f6a60f7
79
ssh.c
79
ssh.c
@ -1905,7 +1905,6 @@ static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
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ssh2_pkt_send_noqueue(ssh, pkt);
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}
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#if 0 /* disused */
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/*
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* Either queue or defer a packet, depending on whether queueing is
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* set.
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@ -1917,7 +1916,6 @@ static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
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else
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ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
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}
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#endif
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/*
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* Send the whole deferred data block constructed by
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@ -1950,6 +1948,74 @@ static void ssh_pkt_defersend(Ssh ssh)
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ssh->deferred_data_size = 0;
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}
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/*
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* Send a packet whose length needs to be disguised (typically
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* passwords or keyboard-interactive responses).
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*/
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static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
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int padsize)
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{
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#if 0
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if (0) {
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/*
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* The simplest way to do this is to adjust the
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* variable-length padding field in the outgoing packet.
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*
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* Currently compiled out, because some Cisco SSH servers
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* don't like excessively padded packets (bah, why's it
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* always Cisco?)
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*/
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pkt->forcepad = padsize;
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ssh2_pkt_send(ssh, pkt);
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} else
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#endif
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{
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/*
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* If we can't do that, however, an alternative approach is
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* to use the pkt_defer mechanism to bundle the packet
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* tightly together with an SSH_MSG_IGNORE such that their
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* combined length is a constant. So first we construct the
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* final form of this packet and defer its sending.
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*/
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ssh2_pkt_defer(ssh, pkt);
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/*
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* Now construct an SSH_MSG_IGNORE which includes a string
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* that's an exact multiple of the cipher block size. (If
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* the cipher is NULL so that the block size is
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* unavailable, we don't do this trick at all, because we
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* gain nothing by it.)
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*/
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if (ssh->cscipher) {
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int stringlen, i;
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stringlen = (256 - ssh->deferred_len);
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stringlen += ssh->cscipher->blksize - 1;
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stringlen -= (stringlen % ssh->cscipher->blksize);
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if (ssh->cscomp) {
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/*
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* Temporarily disable actual compression, so we
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* can guarantee to get this string exactly the
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* length we want it. The compression-disabling
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* routine should return an integer indicating how
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* many bytes we should adjust our string length
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* by.
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*/
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stringlen -=
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ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
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}
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pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
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ssh2_pkt_addstring_start(pkt);
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for (i = 0; i < stringlen; i++) {
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char c = (char) random_byte();
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ssh2_pkt_addstring_data(pkt, &c, 1);
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}
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ssh2_pkt_defer(ssh, pkt);
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}
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ssh_pkt_defersend(ssh);
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}
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}
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/*
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* Send all queued SSH-2 packets. We send them by means of
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* ssh2_pkt_defer_noqueue(), in case they included a pair of
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@ -7374,7 +7440,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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* Send the responses to the server.
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*/
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s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
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s->pktout->forcepad = 256;
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ssh2_pkt_adduint32(s->pktout, s->num_prompts);
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for (i=0; i < s->num_prompts; i++) {
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dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
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@ -7382,7 +7447,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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s->cur_prompt->prompts[i]->result);
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end_log_omission(ssh, s->pktout);
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}
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ssh2_pkt_send(ssh, s->pktout);
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ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
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/*
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* Get the next packet in case it's another
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@ -7452,7 +7517,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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* people who find out how long their password is!
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*/
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s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
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s->pktout->forcepad = 256;
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ssh2_pkt_addstring(s->pktout, s->username);
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ssh2_pkt_addstring(s->pktout, "ssh-connection");
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/* service requested */
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@ -7461,7 +7525,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
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ssh2_pkt_addstring(s->pktout, s->password);
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end_log_omission(ssh, s->pktout);
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ssh2_pkt_send(ssh, s->pktout);
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ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
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logevent("Sent password");
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s->type = AUTH_TYPE_PASSWORD;
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@ -7582,7 +7646,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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* (see above for padding rationale)
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*/
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s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
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s->pktout->forcepad = 256;
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ssh2_pkt_addstring(s->pktout, s->username);
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ssh2_pkt_addstring(s->pktout, "ssh-connection");
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/* service requested */
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@ -7594,7 +7657,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
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s->cur_prompt->prompts[1]->result);
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free_prompts(s->cur_prompt);
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end_log_omission(ssh, s->pktout);
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ssh2_pkt_send(ssh, s->pktout);
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ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
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logevent("Sent new password");
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/*
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