This patch adds support for relaying PAM_ERROR_MSG to clients. This
is useful when PAM_ERROR_MSG returns meaningful information, an
example of this is when pam_nologin is being used and '/etc/nologin'
contains a message for clients attempting to connect.
-Martin
diff -ubNr dropbear-2013.58.orig/auth.h dropbear-2013.58/auth.h
--- dropbear-2013.58.orig/auth.h 2013-04-18 15:58:14.000000000 +0100
+++ dropbear-2013.58/auth.h 2013-04-30 17:37:33.317480220 +0100
@@ -36,6 +36,7 @@
void recv_msg_userauth_request();
void send_msg_userauth_failure(int partial, int incrfail);
void send_msg_userauth_success();
+void send_msg_userauth_banner(buffer **msg);
void svr_auth_password();
void svr_auth_pubkey();
void svr_auth_pam();
diff -ubNr dropbear-2013.58.orig/common-session.c
dropbear-2013.58/common-session.c
--- dropbear-2013.58.orig/common-session.c 2013-04-18 15:58:14.000000000
+0100
+++ dropbear-2013.58/common-session.c 2013-05-01 15:55:20.687368142 +0100
@@ -122,6 +122,8 @@
ses.allowprivport = 0;
+ ses.pam_err = NULL;
+
TRACE(("leave session_init"))
}
diff -ubNr dropbear-2013.58.orig/session.h dropbear-2013.58/session.h
--- dropbear-2013.58.orig/session.h 2013-04-18 15:58:14.000000000 +0100
+++ dropbear-2013.58/session.h 2013-05-02 11:32:32.610072021 +0100
@@ -197,6 +197,8 @@
* really belong here, but nowhere else fits nicely */
int allowprivport;
+ /* buffer for storing PAM error messages */
+ buffer * pam_err;
};
struct serversession {
diff -ubNr dropbear-2013.58.orig/svr-auth.c dropbear-2013.58/svr-auth.c
--- dropbear-2013.58.orig/svr-auth.c 2013-04-18 15:58:14.000000000 +0100
+++ dropbear-2013.58/svr-auth.c 2013-05-01 17:36:28.249791834 +0100
@@ -37,7 +37,6 @@
static void authclear();
static int checkusername(unsigned char *username, unsigned int userlen);
-static void send_msg_userauth_banner();
/* initialise the first time for a session, resetting all parameters */
void svr_authinitialise() {
@@ -82,10 +81,10 @@
/* Send a banner message if specified to the client. The client might
* ignore this, but possibly serves as a legal "no trespassing" sign */
-static void send_msg_userauth_banner() {
+void send_msg_userauth_banner(buffer **banner) {
TRACE(("enter send_msg_userauth_banner"))
- if (svr_opts.banner == NULL) {
+ if ((banner == NULL) || (*banner == NULL)) {
TRACE(("leave send_msg_userauth_banner: banner is NULL"))
return;
}
@@ -93,13 +92,13 @@
CHECKCLEARTOWRITE();
buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_BANNER);
- buf_putstring(ses.writepayload, buf_getptr(svr_opts.banner,
- svr_opts.banner->len), svr_opts.banner->len);
+ buf_putstring(ses.writepayload, buf_getptr(*banner,
+ (*banner)->len), (*banner)->len);
buf_putstring(ses.writepayload, "en", 2);
encrypt_packet();
- buf_free(svr_opts.banner);
- svr_opts.banner = NULL;
+ buf_free(*banner);
+ *banner = NULL;
TRACE(("leave send_msg_userauth_banner"))
}
@@ -121,7 +120,7 @@
/* send the banner if it exists, it will only exist once */
if (svr_opts.banner) {
- send_msg_userauth_banner();
+ send_msg_userauth_banner(&svr_opts.banner);
}
diff -ubNr dropbear-2013.58.orig/svr-authpam.c dropbear-2013.58/svr-authpam.c
--- dropbear-2013.58.orig/svr-authpam.c 2013-04-18 15:58:14.000000000 +0100
+++ dropbear-2013.58/svr-authpam.c 2013-05-01 15:18:38.603729862 +0100
@@ -142,6 +142,22 @@
(*respp) = resp;
break;
+ case PAM_ERROR_MSG:
+
+ if (msg_len > 0) {
+ ses.pam_err = buf_new(msg_len + 4);
+ buf_setpos(ses.pam_err, 0);
+ buf_putbytes(ses.pam_err, "\r\n", 2);
+ buf_putbytes(ses.pam_err, (*msg)->msg, msg_len);
+ buf_putbytes(ses.pam_err, "\r\n", 2);
+ buf_setpos(ses.pam_err, 0);
+
+ send_msg_userauth_banner(&ses.pam_err);
+ }
+
+ rc = PAM_AUTH_ERR;
+ break;
+
default:
TRACE(("Unknown message type"))
rc = PAM_CONV_ERR;
