#
# This patch contains an important bug fix for the PAM password userauth
# conversation function. This bug fix was contributed back to the upstream in
# 2009, but it was not accepted by the upstream. For more information, see
#
--- orig/auth-pam.c Mon Aug 15 16:16:17 2016
+++ new/auth-pam.c Mon Aug 15 16:26:40 2016
@@ -1138,11 +1138,13 @@
free(env);
}
+#ifndef PAM_BUGFIX
/*
* "Blind" conversation function for password authentication. Assumes that
* echo-off prompts are for the password and stores messages for later
* display.
*/
+#endif
static int
sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
struct pam_response **resp, void *data)
@@ -1164,6 +1166,17 @@
for (i = 0; i < n; ++i) {
switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
case PAM_PROMPT_ECHO_OFF:
+#ifdef PAM_BUGFIX
+ /*
+ * PAM conversation function for the password userauth
+ * method (non-interactive) really cannot do any
+ * prompting. We set the PAM_AUTHTOK item in
+ * sshpam_auth_passwd()to avoid conversation. If some
+ * modules still try to converse, then the password
+ * userauth will fail.
+ */
+ goto fail;
+#else
if (sshpam_password == NULL)
goto fail;
if ((reply[i].resp = strdup(sshpam_password)) == NULL)
@@ -1170,6 +1183,7 @@
goto fail;
reply[i].resp_retcode = PAM_SUCCESS;
break;
+#endif
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
len = strlen(PAM_MSG_MEMBER(msg, i, msg));
@@ -1205,6 +1219,9 @@
int
sshpam_auth_passwd(Authctxt *authctxt, const char *password)
{
+#ifdef PAM_BUGFIX
+ int set_item_rtn;
+#endif
int flags = (options.permit_empty_passwd == 0 ?
PAM_DISALLOW_NULL_AUTHTOK : 0);
char *fake = NULL;
@@ -1225,6 +1242,15 @@
options.permit_root_login != PERMIT_YES))
sshpam_password = fake = fake_password(password);
+#ifdef PAM_BUGFIX
+ sshpam_err = pam_set_item(sshpam_handle, PAM_AUTHTOK, sshpam_password);
+ if (sshpam_err != PAM_SUCCESS) {
+ debug("PAM: %s: failed to set PAM_AUTHTOK: %s", __func__,
+ pam_strerror(sshpam_handle, sshpam_err));
+ return 0;
+ }
+#endif
+
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
(const void *)&passwd_conv);
if (sshpam_err != PAM_SUCCESS)
@@ -1236,6 +1262,16 @@
free(fake);
if (sshpam_err == PAM_MAXTRIES)
sshpam_set_maxtries_reached(1);
+
+#ifdef PAM_BUGFIX
+ set_item_rtn = pam_set_item(sshpam_handle, PAM_AUTHTOK, NULL);
+ if (set_item_rtn != PAM_SUCCESS) {
+ debug("PAM: %s: failed to set PAM_AUTHTOK: %s", __func__,
+ pam_strerror(sshpam_handle, set_item_rtn));
+ return 0;
+ }
+#endif
+
if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
debug("PAM: password authentication accepted for %.100s",
authctxt->user);