Adding upstream version 1.8.27.upstream/1.8.27upstream

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

1 files changed, 335 insertions, 0 deletions

diff --git a/plugins/sudoers/auth/kerb5.c b/plugins/sudoers/auth/kerb5.c
new file mode 100644
index 0000000..247981c
--- /dev/null
+++ b/plugins/sudoers/auth/kerb5.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (c) 1999-2005, 2007-2008, 2010-2015
+ *	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>
+
+#ifdef HAVE_KERB5
+
+#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_STRING_H */
+#include <unistd.h>
+#include <pwd.h>
+#include <krb5.h>
+#ifdef HAVE_HEIMDAL
+#include <com_err.h>
+#endif
+
+#include "sudoers.h"
+#include "sudo_auth.h"
+
+#ifdef HAVE_HEIMDAL
+# define extract_name(c, p)		krb5_principal_get_comp_string(c, p, 1)
+# define krb5_free_data_contents(c, d)	krb5_data_free(d)
+#else
+# define extract_name(c, p)		(krb5_princ_component(c, p, 1)->data)
+#endif
+
+#ifndef HAVE_KRB5_VERIFY_USER
+static int verify_krb_v5_tgt(krb5_context, krb5_creds *, char *);
+#endif
+static struct _sudo_krb5_data {
+    krb5_context	sudo_context;
+    krb5_principal	princ;
+    krb5_ccache		ccache;
+} sudo_krb5_data = { NULL, NULL, NULL };
+typedef struct _sudo_krb5_data *sudo_krb5_datap;
+
+#ifdef SUDO_KRB5_INSTANCE
+static const char *sudo_krb5_instance = SUDO_KRB5_INSTANCE;
+#else
+static const char *sudo_krb5_instance = NULL;
+#endif
+
+#ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_ALLOC
+static krb5_error_code
+krb5_get_init_creds_opt_alloc(krb5_context context,
+    krb5_get_init_creds_opt **opts)
+{
+    *opts = malloc(sizeof(krb5_get_init_creds_opt));
+    if (*opts == NULL)
+	return KRB5_CC_NOMEM;
+    krb5_get_init_creds_opt_init(*opts);
+    return 0;
+}
+
+static void
+krb5_get_init_creds_opt_free(krb5_get_init_creds_opt *opts)
+{
+    free(opts);
+}
+#endif
+
+int
+sudo_krb5_setup(struct passwd *pw, char **promptp, sudo_auth *auth)
+{
+    static char	*krb5_prompt;
+    debug_decl(sudo_krb5_init, SUDOERS_DEBUG_AUTH)
+
+    if (krb5_prompt == NULL) {
+	krb5_context	sudo_context;
+	krb5_principal	princ;
+	char		*pname;
+	krb5_error_code	error;
+
+	sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
+	princ = ((sudo_krb5_datap) auth->data)->princ;
+
+	/*
+	 * Really, we need to tell the caller not to prompt for password. The
+	 * API does not currently provide this unless the auth is standalone.
+	 */
+	if ((error = krb5_unparse_name(sudo_context, princ, &pname))) {
+	    log_warningx(0,
+		N_("%s: unable to convert principal to string ('%s'): %s"),
+		auth->name, pw->pw_name, error_message(error));
+	    debug_return_int(AUTH_FAILURE);
+	}
+
+	/* Only rewrite prompt if user didn't specify their own. */
+	/*if (!strcmp(prompt, PASSPROMPT)) { */
+	    if (asprintf(&krb5_prompt, "Password for %s: ", pname) == -1) {
+		log_warningx(0, N_("unable to allocate memory"));
+		free(pname);
+		debug_return_int(AUTH_FATAL);
+	    }
+	/*}*/
+	free(pname);
+    }
+    *promptp = krb5_prompt;
+
+    debug_return_int(AUTH_SUCCESS);
+}
+
+int
+sudo_krb5_init(struct passwd *pw, sudo_auth *auth)
+{
+    krb5_context	sudo_context;
+    krb5_error_code 	error;
+    char		cache_name[64], *pname = pw->pw_name;
+    debug_decl(sudo_krb5_init, SUDOERS_DEBUG_AUTH)
+
+    auth->data = (void *) &sudo_krb5_data; /* Stash all our data here */
+
+    if (sudo_krb5_instance != NULL) {
+	int len = asprintf(&pname, "%s%s%s", pw->pw_name,
+	    sudo_krb5_instance[0] != '/' ? "/" : "", sudo_krb5_instance);
+	if (len == -1) {
+	    log_warningx(0, N_("unable to allocate memory"));
+	    debug_return_int(AUTH_FATAL);
+	}
+    }
+
+#ifdef HAVE_KRB5_INIT_SECURE_CONTEXT
+    error = krb5_init_secure_context(&(sudo_krb5_data.sudo_context));
+#else
+    error = krb5_init_context(&(sudo_krb5_data.sudo_context));
+#endif
+    if (error)
+	goto done;
+    sudo_context = sudo_krb5_data.sudo_context;
+
+    error = krb5_parse_name(sudo_context, pname, &(sudo_krb5_data.princ));
+    if (error) {
+	log_warningx(0, N_("%s: unable to parse '%s': %s"), auth->name, pname,
+	    error_message(error));
+	goto done;
+    }
+
+    (void) snprintf(cache_name, sizeof(cache_name), "MEMORY:sudocc_%ld",
+		    (long) getpid());
+    if ((error = krb5_cc_resolve(sudo_context, cache_name,
+	&(sudo_krb5_data.ccache)))) {
+	log_warningx(0, N_("%s: unable to resolve credential cache: %s"),
+	    auth->name, error_message(error));
+	goto done;
+    }
+
+done:
+    if (sudo_krb5_instance != NULL)
+	free(pname);
+    debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
+}
+
+#ifdef HAVE_KRB5_VERIFY_USER
+int
+sudo_krb5_verify(struct passwd *pw, char *pass, sudo_auth *auth, struct sudo_conv_callback *callback)
+{
+    krb5_context	sudo_context;
+    krb5_principal	princ;
+    krb5_ccache		ccache;
+    krb5_error_code	error;
+    debug_decl(sudo_krb5_verify, SUDOERS_DEBUG_AUTH)
+
+    sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
+    princ = ((sudo_krb5_datap) auth->data)->princ;
+    ccache = ((sudo_krb5_datap) auth->data)->ccache;
+
+    error = krb5_verify_user(sudo_context, princ, ccache, pass, 1, NULL);
+    debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
+}
+#else
+int
+sudo_krb5_verify(struct passwd *pw, char *pass, sudo_auth *auth, struct sudo_conv_callback *callback)
+{
+    krb5_context	sudo_context;
+    krb5_principal	princ;
+    krb5_creds		credbuf, *creds = NULL;
+    krb5_ccache		ccache;
+    krb5_error_code	error;
+    krb5_get_init_creds_opt *opts = NULL;
+    debug_decl(sudo_krb5_verify, SUDOERS_DEBUG_AUTH)
+
+    sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
+    princ = ((sudo_krb5_datap) auth->data)->princ;
+    ccache = ((sudo_krb5_datap) auth->data)->ccache;
+
+    /* Set default flags based on the local config file. */
+    error = krb5_get_init_creds_opt_alloc(sudo_context, &opts);
+    if (error) {
+	log_warningx(0, N_("%s: unable to allocate options: %s"), auth->name,
+	    error_message(error));
+	goto done;
+    }
+#ifdef HAVE_HEIMDAL
+    krb5_get_init_creds_opt_set_default_flags(sudo_context, NULL,
+	krb5_principal_get_realm(sudo_context, princ), opts);
+#endif
+
+    /* Note that we always obtain a new TGT to verify the user */
+    if ((error = krb5_get_init_creds_password(sudo_context, &credbuf, princ,
+					     pass, krb5_prompter_posix,
+					     NULL, 0, NULL, opts))) {
+	/* Don't print error if just a bad password */
+	if (error != KRB5KRB_AP_ERR_BAD_INTEGRITY) {
+	    log_warningx(0, N_("%s: unable to get credentials: %s"),
+		auth->name, error_message(error));
+	}
+	goto done;
+    }
+    creds = &credbuf;
+
+    /* Verify the TGT to prevent spoof attacks. */
+    if ((error = verify_krb_v5_tgt(sudo_context, creds, auth->name)))
+	goto done;
+
+    /* Store credential in cache. */
+    if ((error = krb5_cc_initialize(sudo_context, ccache, princ))) {
+	log_warningx(0, N_("%s: unable to initialize credential cache: %s"),
+	    auth->name, error_message(error));
+    } else if ((error = krb5_cc_store_cred(sudo_context, ccache, creds))) {
+	log_warningx(0, N_("%s: unable to store credential in cache: %s"),
+	    auth->name, error_message(error));
+    }
+
+done:
+    if (opts) {
+#ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_FREE_TWO_ARGS
+	krb5_get_init_creds_opt_free(sudo_context, opts);
+#else
+	krb5_get_init_creds_opt_free(opts);
+#endif
+    }
+    if (creds)
+	krb5_free_cred_contents(sudo_context, creds);
+    debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
+}
+#endif
+
+int
+sudo_krb5_cleanup(struct passwd *pw, sudo_auth *auth)
+{
+    krb5_context	sudo_context;
+    krb5_principal	princ;
+    krb5_ccache		ccache;
+    debug_decl(sudo_krb5_cleanup, SUDOERS_DEBUG_AUTH)
+
+    sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
+    princ = ((sudo_krb5_datap) auth->data)->princ;
+    ccache = ((sudo_krb5_datap) auth->data)->ccache;
+
+    if (sudo_context) {
+	if (ccache)
+	    krb5_cc_destroy(sudo_context, ccache);
+	if (princ)
+	    krb5_free_principal(sudo_context, princ);
+	krb5_free_context(sudo_context);
+    }
+
+    debug_return_int(AUTH_SUCCESS);
+}
+
+#ifndef HAVE_KRB5_VERIFY_USER
+/*
+ * Verify the Kerberos ticket-granting ticket just retrieved for the
+ * user.  If the Kerberos server doesn't respond, assume the user is
+ * trying to fake us out (since we DID just get a TGT from what is
+ * supposedly our KDC).
+ *
+ * Returns 0 for successful authentication, non-zero for failure.
+ */
+static int
+verify_krb_v5_tgt(krb5_context sudo_context, krb5_creds *cred, char *auth_name)
+{
+    krb5_error_code	error;
+    krb5_principal	server;
+    krb5_verify_init_creds_opt vopt;
+    debug_decl(verify_krb_v5_tgt, SUDOERS_DEBUG_AUTH)
+
+    /*
+     * Get the server principal for the local host.
+     * (Use defaults of "host" and canonicalized local name.)
+     */
+    if ((error = krb5_sname_to_principal(sudo_context, NULL, NULL,
+					KRB5_NT_SRV_HST, &server))) {
+	log_warningx(0, N_("%s: unable to get host principal: %s"), auth_name,
+	    error_message(error));
+	debug_return_int(-1);
+    }
+
+    /* Initialize verify opts and set secure mode */
+    krb5_verify_init_creds_opt_init(&vopt);
+    krb5_verify_init_creds_opt_set_ap_req_nofail(&vopt, 1);
+
+    /* verify the Kerberos ticket-granting ticket we just retrieved */
+    error = krb5_verify_init_creds(sudo_context, cred, server, NULL,
+				   NULL, &vopt);
+    krb5_free_principal(sudo_context, server);
+    if (error) {
+	log_warningx(0, N_("%s: Cannot verify TGT! Possible attack!: %s"),
+	    auth_name, error_message(error));
+    }
+    debug_return_int(error);
+}
+#endif
+
+#endif /* HAVE_KERB5 */