From 0a66ad22e54c72690ec2a29a019767c55c5281fc Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 18 Oct 2024 20:22:57 +1100 Subject: [PATCH] pppd: Remove passprompt plugin This is prompted by a number of factors: * It was more useful back in the dial-up days, but no-one uses dial-up any more * In many cases there will be no terminal accessible to the prompter program at the point where the prompter is run * The passwordfd plugin does much the same thing but does it more cleanly and securely * The handling of privileges and file descriptors needs to be audited thoroughly. Signed-off-by: Paul Mackerras CVE: CVE-2024-58250 Upstream-Status: Backport [https://github.com/ppp-project/ppp/commit/0a66ad22e54c72690ec2a29a019767c55c5281fc] Signed-off-by: Peter Marko --- pppd/plugins/Makefile.am | 6 +- pppd/plugins/passprompt.c | 137 -------------------------------------- 2 files changed, 1 insertion(+), 142 deletions(-) delete mode 100644 pppd/plugins/passprompt.c diff --git a/pppd/plugins/Makefile.am b/pppd/plugins/Makefile.am index 2826148..9480d51 100644 --- a/pppd/plugins/Makefile.am +++ b/pppd/plugins/Makefile.am @@ -1,4 +1,4 @@ -pppd_plugin_LTLIBRARIES = minconn.la passprompt.la passwordfd.la winbind.la +pppd_plugin_LTLIBRARIES = minconn.la passwordfd.la winbind.la pppd_plugindir = $(PPPD_PLUGIN_DIR) PLUGIN_CPPFLAGS = -I${top_srcdir} @@ -8,10 +8,6 @@ minconn_la_CPPFLAGS = $(PLUGIN_CPPFLAGS) minconn_la_LDFLAGS = $(PLUGIN_LDFLAGS) minconn_la_SOURCES = minconn.c -passprompt_la_CPPFLAGS = $(PLUGIN_CPPFLAGS) -passprompt_la_LDFLAGS = $(PLUGIN_LDFLAGS) -passprompt_la_SOURCES = passprompt.c - passwordfd_la_CPPFLAGS = $(PLUGIN_CPPFLAGS) passwordfd_la_LDFLAGS = $(PLUGIN_LDFLAGS) passwordfd_la_SOURCES = passwordfd.c diff --git a/pppd/plugins/passprompt.c b/pppd/plugins/passprompt.c deleted file mode 100644 index 7779d51..0000000 --- a/pppd/plugins/passprompt.c +++ /dev/null @@ -1,137 +0,0 @@ -/* - * passprompt.c - pppd plugin to invoke an external PAP password prompter - * - * Copyright 1999 Paul Mackerras, Alan Curry. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include - -char pppd_version[] = PPPD_VERSION; - -static char promptprog[PATH_MAX+1]; -static int promptprog_refused = 0; - -static struct option options[] = { - { "promptprog", o_string, promptprog, - "External PAP password prompting program", - OPT_STATIC, NULL, PATH_MAX }, - { NULL } -}; - -static int promptpass(char *user, char *passwd) -{ - int p[2]; - pid_t kid; - int readgood, wstat, ret; - ssize_t red; - - if (promptprog_refused || promptprog[0] == 0 || access(promptprog, X_OK) < 0) - return -1; /* sorry, can't help */ - - if (!passwd) - return 1; - - if (pipe(p)) { - warn("Can't make a pipe for %s", promptprog); - return 0; - } - if ((kid = fork()) == (pid_t) -1) { - warn("Can't fork to run %s", promptprog); - close(p[0]); - close(p[1]); - return 0; - } - if (!kid) { - /* we are the child, exec the program */ - char *argv[5], fdstr[32]; - ppp_sys_close(); - closelog(); - close(p[0]); - ret = seteuid(getuid()); - if (ret != 0) { - warn("Couldn't set effective user id"); - } - ret = setegid(getgid()); - if (ret != 0) { - warn("Couldn't set effective user id"); - } - sprintf(fdstr, "%d", p[1]); - argv[0] = promptprog; - argv[1] = strdup(user); - argv[2] = strdup(ppp_remote_name()); - argv[3] = fdstr; - argv[4] = 0; - execv(*argv, argv); - _exit(127); - } - - /* we are the parent, read the password from the pipe */ - close(p[1]); - readgood = 0; - do { - red = read(p[0], passwd + readgood, MAXSECRETLEN-1 - readgood); - if (red == 0) - break; - if (red < 0) { - if (errno == EINTR && !ppp_signaled(SIGTERM)) - continue; - error("Can't read secret from %s: %m", promptprog); - readgood = -1; - break; - } - readgood += red; - } while (readgood < MAXSECRETLEN - 1); - close(p[0]); - - /* now wait for child to exit */ - while (waitpid(kid, &wstat, 0) < 0) { - if (errno != EINTR || ppp_signaled(SIGTERM)) { - warn("error waiting for %s: %m", promptprog); - break; - } - } - - if (readgood < 0) - return 0; - passwd[readgood] = 0; - if (!WIFEXITED(wstat)) - warn("%s terminated abnormally", promptprog); - if (WEXITSTATUS(wstat)) { - warn("%s exited with code %d", promptprog, WEXITSTATUS(wstat)); - /* code when cancel was hit in the prompt prog */ - if (WEXITSTATUS(wstat) == 128) { - promptprog_refused = 1; - } - return -1; - } - return 1; -} - -void plugin_init(void) -{ - ppp_add_options(options); - pap_passwd_hook = promptpass; -#ifdef PPP_WITH_EAPTLS - eaptls_passwd_hook = promptpass; -#endif -}