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Use the packet dispatch table to handle USERAUTH_BANNER messages, which should

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hopefully solve `drop-banner'. I haven't been able to test the failure case,
but the behaviour with OpenSSH appears no worse.

[originally from svn r5772]
[this svn revision also touched putty-wishlist]
This commit is contained in:
Jacob Nevins 2005-05-12 15:09:35 +00:00
parent c2abdbc360
commit aa43d817d2
1 changed files with 34 additions and 8 deletions
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42
ssh.c
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@ -748,6 +748,7 @@ struct ssh_tag {
*/ */
int fallback_cmd; int fallback_cmd;
bufchain banner; /* accumulates banners during do_ssh2_authconn */
/* /*
* Used for username and password input. * Used for username and password input.
*/ */
@ -6387,6 +6388,21 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
} }
} }
/*
* Buffer banner messages for later display at some convenient point.
*/
static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
{
/* Arbitrary limit to prevent unbounded inflation of buffer */
if (bufchain_size(&ssh->banner) <= 131072) {
char *banner = NULL;
int size = 0;
ssh_pkt_getstring(pktin, &banner, &size);
if (banner)
bufchain_add(&ssh->banner, banner, size);
}
}
/* Helper function to deal with sending tty modes for "pty-req" */ /* Helper function to deal with sending tty modes for "pty-req" */
static void ssh2_send_ttymode(void *data, char *mode, char *val) static void ssh2_send_ttymode(void *data, char *mode, char *val)
{ {
@ -6511,6 +6527,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
*/ */
s->username[0] = '\0'; s->username[0] = '\0';
s->got_username = FALSE; s->got_username = FALSE;
bufchain_init(&ssh->banner);
ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
ssh2_msg_userauth_banner;
while (!s->we_are_in) { while (!s->we_are_in) {
/* /*
* Get a username. * Get a username.
@ -6611,9 +6630,14 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
*/ */
if (!s->gotit) if (!s->gotit)
crWaitUntilV(pktin); crWaitUntilV(pktin);
while (pktin->type == SSH2_MSG_USERAUTH_BANNER) { /*
char *banner; * Now is a convenient point to spew any banner material
int size; * that we've accumulated. (This should ensure that when
* we exit the auth loop, we haven't any left to deal
* with.)
*/
{
int size = bufchain_size(&ssh->banner);
/* /*
* Don't show the banner if we're operating in * Don't show the banner if we're operating in
* non-verbose non-interactive mode. (It's probably * non-verbose non-interactive mode. (It's probably
@ -6622,12 +6646,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
* the banner will screw up processing on the * the banner will screw up processing on the
* output of (say) plink.) * output of (say) plink.)
*/ */
if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) { if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
ssh_pkt_getstring(pktin, &banner, &size); char *banner = snewn(size, char);
if (banner) bufchain_fetch(&ssh->banner, banner, size);
c_write_untrusted(ssh, banner, size); c_write_untrusted(ssh, banner, size);
sfree(banner);
} }
crWaitUntilV(pktin); bufchain_clear(&ssh->banner);
} }
if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) { if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
logevent("Access granted"); logevent("Access granted");
@ -7253,6 +7278,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
} }
} }
} }
ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
/* /*
* Now the connection protocol has started, one way or another. * Now the connection protocol has started, one way or another.