Adding upstream version 1.8.27.upstream/1.8.27upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 333 insertions, 0 deletions

diff --git a/plugins/sudoers/check.c b/plugins/sudoers/check.c
new file mode 100644
index 0000000..92f859c
--- /dev/null
+++ b/plugins/sudoers/check.c
@@ -0,0 +1,333 @@
+/*
+ * Copyright (c) 1993-1996,1998-2005, 2007-2018
+ *	Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Sponsored in part by the Defense Advanced Research Projects
+ * Agency (DARPA) and Air Force Research Laboratory, Air Force
+ * Materiel Command, USAF, under agreement number F39502-99-1-0512.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <time.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <grp.h>
+
+#include "sudoers.h"
+#include "check.h"
+
+static bool display_lecture(int);
+static struct passwd *get_authpw(int);
+
+struct getpass_closure {
+    void *cookie;
+    struct passwd *auth_pw;
+};
+
+/*
+ * Called when getpass is suspended so we can drop the lock.
+ */
+static int
+getpass_suspend(int signo, void *vclosure)
+{
+    struct getpass_closure *closure = vclosure;
+
+    timestamp_close(closure->cookie);
+    closure->cookie = NULL;
+    return 0;
+}
+
+/*
+ * Called when getpass is resumed so we can reacquire the lock.
+ */
+static int
+getpass_resume(int signo, void *vclosure)
+{
+    struct getpass_closure *closure = vclosure;
+
+    closure->cookie = timestamp_open(user_name, user_sid);
+    if (closure->cookie == NULL)
+	return -1;
+    if (!timestamp_lock(closure->cookie, closure->auth_pw))
+	return -1;
+    return 0;
+}
+
+/*
+ * Returns true if the user successfully authenticates, false if not
+ * or -1 on fatal error.
+ */
+static int
+check_user_interactive(int validated, int mode, struct passwd *auth_pw)
+{
+    struct sudo_conv_callback cb, *callback = NULL;
+    struct getpass_closure closure;
+    int status = TS_ERROR;
+    int ret = -1;
+    char *prompt;
+    bool lectured;
+    debug_decl(check_user_interactive, SUDOERS_DEBUG_AUTH)
+
+    /* Setup closure for getpass_{suspend,resume} */
+    closure.auth_pw = auth_pw;
+    closure.cookie = NULL;
+    sudo_pw_addref(closure.auth_pw);
+
+    /* Open, lock and read time stamp file if we are using it. */
+    if (!ISSET(mode, MODE_IGNORE_TICKET)) {
+	/* Open time stamp file and check its status. */
+	closure.cookie = timestamp_open(user_name, user_sid);
+	if (timestamp_lock(closure.cookie, closure.auth_pw))
+	    status = timestamp_status(closure.cookie, closure.auth_pw);
+
+	/* Construct callback for getpass function. */
+	memset(&cb, 0, sizeof(cb));
+	cb.version = SUDO_CONV_CALLBACK_VERSION;
+	cb.closure = &closure;
+	cb.on_suspend = getpass_suspend;
+	cb.on_resume = getpass_resume;
+	callback = &cb;
+    }
+
+    switch (status) {
+    case TS_FATAL:
+	/* Fatal error (usually setuid failure), unsafe to proceed. */
+	goto done;
+
+    case TS_CURRENT:
+	/* Time stamp file is valid and current. */
+	if (!ISSET(validated, FLAG_CHECK_USER)) {
+	    ret = true;
+	    break;
+	}
+	sudo_debug_printf(SUDO_DEBUG_INFO,
+	    "%s: check user flag overrides time stamp", __func__);
+	/* FALLTHROUGH */
+
+    default:
+	/* Bail out if we are non-interactive and a password is required */
+	if (ISSET(mode, MODE_NONINTERACTIVE)) {
+	    validated |= FLAG_NON_INTERACTIVE;
+	    log_auth_failure(validated, 0);
+	    goto done;
+	}
+
+	/* XXX - should not lecture if askpass helper is being used. */
+	lectured = display_lecture(status);
+
+	/* Expand any escapes in the prompt. */
+	prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
+	    closure.auth_pw->pw_name);
+	if (prompt == NULL)
+	    goto done;
+
+	ret = verify_user(closure.auth_pw, prompt, validated, callback);
+	if (ret == true && lectured)
+	    (void)set_lectured();	/* lecture error not fatal */
+	free(prompt);
+	break;
+    }
+
+    /*
+     * Only update time stamp if user was validated.
+     * Failure to update the time stamp is not a fatal error.
+     */
+    if (ret == true && ISSET(validated, VALIDATE_SUCCESS) && status != TS_ERROR)
+	(void)timestamp_update(closure.cookie, closure.auth_pw);
+done:
+    if (closure.cookie != NULL)
+	timestamp_close(closure.cookie);
+    sudo_pw_delref(closure.auth_pw);
+
+    debug_return_int(ret);
+}
+
+/*
+ * Returns true if the user successfully authenticates, false if not
+ * or -1 on error.
+ */
+int
+check_user(int validated, int mode)
+{
+    struct passwd *auth_pw;
+    int ret = -1;
+    bool exempt = false;
+    debug_decl(check_user, SUDOERS_DEBUG_AUTH)
+
+    /*
+     * Init authentication system regardless of whether we need a password.
+     * Required for proper PAM session support.
+     */
+    if ((auth_pw = get_authpw(mode)) == NULL)
+	goto done;
+    if (sudo_auth_init(auth_pw) == -1)
+	goto done;
+
+    /*
+     * Don't prompt for the root passwd or if the user is exempt.
+     * If the user is not changing uid/gid, no need for a password.
+     */
+    if (!def_authenticate || user_is_exempt()) {
+	sudo_debug_printf(SUDO_DEBUG_INFO, "%s: %s", __func__,
+	    !def_authenticate ? "authentication disabled" :
+	    "user exempt from authentication");
+	exempt = true;
+	ret = true;
+	goto done;
+    }
+    if (user_uid == 0 || (user_uid == runas_pw->pw_uid &&
+	(!runas_gr || user_in_group(sudo_user.pw, runas_gr->gr_name)))) {
+#ifdef HAVE_SELINUX
+	if (user_role == NULL && user_type == NULL)
+#endif
+#ifdef HAVE_PRIV_SET
+	if (runas_privs == NULL && runas_limitprivs == NULL)
+#endif
+	{
+	    sudo_debug_printf(SUDO_DEBUG_INFO,
+		"%s: user running command as self", __func__);
+	    ret = true;
+	    goto done;
+	}
+    }
+
+    ret = check_user_interactive(validated, mode, auth_pw);
+
+done:
+    if (ret == true) {
+	/* The approval function may disallow a user post-authentication. */
+	ret = sudo_auth_approval(auth_pw, validated, exempt);
+    }
+    sudo_auth_cleanup(auth_pw);
+    sudo_pw_delref(auth_pw);
+
+    debug_return_int(ret);
+}
+
+/*
+ * Display sudo lecture (standard or custom).
+ * Returns true if the user was lectured, else false.
+ */
+static bool
+display_lecture(int status)
+{
+    FILE *fp;
+    char buf[BUFSIZ];
+    ssize_t nread;
+    struct sudo_conv_message msg;
+    struct sudo_conv_reply repl;
+    debug_decl(lecture, SUDOERS_DEBUG_AUTH)
+
+    if (def_lecture == never ||
+	(def_lecture == once && already_lectured(status)))
+	debug_return_bool(false);
+
+    memset(&msg, 0, sizeof(msg));
+    memset(&repl, 0, sizeof(repl));
+
+    if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
+	while ((nread = fread(buf, sizeof(char), sizeof(buf) - 1, fp)) != 0) {
+	    buf[nread] = '\0';
+	    msg.msg_type = SUDO_CONV_ERROR_MSG;
+	    msg.msg = buf;
+	    sudo_conv(1, &msg, &repl, NULL);
+	}
+	fclose(fp);
+    } else {
+	msg.msg_type = SUDO_CONV_ERROR_MSG;
+	msg.msg = _("\n"
+	    "We trust you have received the usual lecture from the local System\n"
+	    "Administrator. It usually boils down to these three things:\n\n"
+	    "    #1) Respect the privacy of others.\n"
+	    "    #2) Think before you type.\n"
+	    "    #3) With great power comes great responsibility.\n\n");
+	sudo_conv(1, &msg, &repl, NULL);
+    }
+    debug_return_bool(true);
+}
+
+/*
+ * Checks if the user is exempt from supplying a password.
+ */
+bool
+user_is_exempt(void)
+{
+    bool ret = false;
+    debug_decl(user_is_exempt, SUDOERS_DEBUG_AUTH)
+
+    if (def_exempt_group)
+	ret = user_in_group(sudo_user.pw, def_exempt_group);
+    debug_return_bool(ret);
+}
+
+/*
+ * Get passwd entry for the user we are going to authenticate as.
+ * By default, this is the user invoking sudo.  In the most common
+ * case, this matches sudo_user.pw or runas_pw.
+ */
+static struct passwd *
+get_authpw(int mode)
+{
+    struct passwd *pw = NULL;
+    debug_decl(get_authpw, SUDOERS_DEBUG_AUTH)
+
+    if (ISSET(mode, (MODE_CHECK|MODE_LIST))) {
+	/* In list mode we always prompt for the user's password. */
+	sudo_pw_addref(sudo_user.pw);
+	pw = sudo_user.pw;
+    } else {
+	if (def_rootpw) {
+	    if ((pw = sudo_getpwuid(ROOT_UID)) == NULL) {
+		log_warningx(SLOG_SEND_MAIL, N_("unknown uid: %u"), ROOT_UID);
+	    }
+	} else if (def_runaspw) {
+	    if ((pw = sudo_getpwnam(def_runas_default)) == NULL) {
+		log_warningx(SLOG_SEND_MAIL,
+		    N_("unknown user: %s"), def_runas_default);
+	    }
+	} else if (def_targetpw) {
+	    if (runas_pw->pw_name == NULL) {
+		/* This should never be NULL as we fake up the passwd struct */
+		log_warningx(SLOG_RAW_MSG, N_("unknown uid: %u"),
+		    (unsigned int) runas_pw->pw_uid);
+	    } else {
+		sudo_pw_addref(runas_pw);
+		pw = runas_pw;
+	    }
+	} else {
+	    sudo_pw_addref(sudo_user.pw);
+	    pw = sudo_user.pw;
+	}
+    }
+
+    debug_return_ptr(pw);
+}