Merge pull request neutrinolabs#2439 from matt335672/v0_9_remove_pass…

…wd_from_auth_info

[V0.9] Remove unnecesssary data from struct auth_info

sesman/libscp/libscp_session.c

@@ -427,14 +427,29 @@ scp_session_set_guid(struct SCP_SESSION *s, const struct guid *guid)
  return 0;
 }
 
+/*******************************************************************/
+static void
+clear_and_free_string(char *p)
+{
+ if (p != NULL)
+ {
+ char *cp;
+ for (cp = p ; *cp != '\0'; ++cp)
+ {
+ *cp = '\0';
+ }
+ g_free(p);
+ }
+}
+
 /*******************************************************************/
 void
 scp_session_destroy(struct SCP_SESSION *s)
 {
  if (s != NULL)
  {
  g_free(s->username);
- g_free(s->password);
+ clear_and_free_string(s->password);
  g_free(s->hostname);
  g_free(s->domain);
  g_free(s->program);

sesman/verify_user_pam.c

@@ -36,21 +36,17 @@
 #include <stdio.h>
 #include <security/pam_appl.h>
 
-/* Defines the maximum size of a username or password. With pam there is no real limit */
-#define MAX_BUF 8192
-
+/* Allows the conversation function to find the username and password */
 struct t_user_pass
 {
- char user[MAX_BUF];
- char pass[MAX_BUF];
+ const char *user;
+ const char *pass;
 };
 
 struct t_auth_info
 {
- struct t_user_pass user_pass;
  int session_opened;
  int did_setcred;
- struct pam_conv pamc;
  pam_handle_t *ph;
 };
 
@@ -148,7 +144,18 @@ verify_pam_conv(int num_msg, const struct pam_message **msg,
  {
  case PAM_PROMPT_ECHO_OFF: /* password */
  user_pass = (struct t_user_pass *) appdata_ptr;
- reply[i].resp = g_strdup(user_pass->pass);
+ /* Check this function isn't being called
+ * later than we expected */
+ if (user_pass == NULL)
+ {
+ LOG(LOG_LEVEL_ERROR,
+ "verify_pam_conv: Password unavailable");
+ reply[i].resp = g_strdup("????");
+ }
+ else
+ {
+ reply[i].resp = g_strdup(user_pass->pass);
+ }
  break;
 
  case PAM_ERROR_MSG:
@@ -217,14 +224,19 @@ auth_userpass(const char *user, const char *pass, int *errorcode)
  int error;
  struct t_auth_info *auth_info;
  char service_name[256];
+ struct t_user_pass user_pass = {user, pass};
+ struct pam_conv pamc = {verify_pam_conv, (void *) &user_pass};
 
- get_service_name(service_name);
  auth_info = g_new0(struct t_auth_info, 1);
- g_strncpy(auth_info->user_pass.user, user, MAX_BUF - 1);
- g_strncpy(auth_info->user_pass.pass, pass, MAX_BUF - 1);
- auth_info->pamc.conv = &verify_pam_conv;
- auth_info->pamc.appdata_ptr = &(auth_info->user_pass);
- error = pam_start(service_name, user, &(auth_info->pamc), &(auth_info->ph));
+ if (auth_info == NULL)
+ {
+ LOG(LOG_LEVEL_ERROR, "auth_userpass: No memory");
+ error = PAM_BUF_ERR;
+ return 0;
+ }
+
+ get_service_name(service_name);
+ error = pam_start(service_name, user, &pamc, &(auth_info->ph));
 
  if (error != PAM_SUCCESS)
  {
@@ -281,6 +293,16 @@ auth_userpass(const char *user, const char *pass, int *errorcode)
  return 0;
  }
 
+ /* Set the appdata_ptr passed to the conversation function to
+ * NULL, as the existing value is going out of scope */
+ pamc.appdata_ptr = NULL;
+ error = pam_set_item(auth_info->ph, PAM_CONV, &pamc);
+ if (error != PAM_SUCCESS)
+ {
+ LOG(LOG_LEVEL_ERROR, "pam_set_item(PAM_CONV) failed: %s",
+ pam_strerror(auth_info->ph, error));
+ }
+
  return (long)auth_info;
 }