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/*
* Option handling for pam-afs-session.
*
* Parses the PAM command line for options to pam-afs-session and fills out an
* allocated structure with those details.
*
* Written by Russ Allbery <rra@stanford.edu>
* Copyright 2006, 2007, 2008
* Board of Trustees, Leland Stanford Jr. University
* See LICENSE for licensing terms.
*/
#include "config.h"
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
/* AIX doesn't have the appdefault functions. */
#ifdef HAVE_KERBEROS
# include <krb5.h>
# ifndef HAVE_KRB5_APPDEFAULT_STRING
# include "compat-aix.c"
# endif
#endif
#include "internal.h"
/*
* Allocate a new struct pam_args and initialize its data members.
*/
static struct pam_args *
pamafs_args_new(void)
{
struct pam_args *args;
args = calloc(1, sizeof(struct pam_args));
if (args == NULL)
return NULL;
args->program = NULL;
return args;
}
/*
* Free the allocated args struct and any memory it points to.
*/
void
pamafs_args_free(struct pam_args *args)
{
if (args != NULL) {
if (args->afs_cells != NULL)
free(args->afs_cells);
if (args->cells != NULL)
free(args->cells);
if (args->program != NULL)
free(args->program);
free(args);
}
}
#ifdef HAVE_KERBEROS
/*
* Load a string option from Kerberos appdefaults. This requires an annoying
* workaround because one cannot specify a default value of NULL.
*/
static void
default_string(krb5_context c, const char *opt, const char *defval,
char **result)
{
if (defval == NULL)
defval = "";
krb5_appdefault_string(c, "pam-afs-session", NULL, opt, defval, result);
if (*result != NULL && (*result)[0] == '\0') {
free(*result);
*result = NULL;
}
}
/*
* Load a number option from Kerberos appdefaults. The native interface
* doesn't support numbers, so we actually read a string and then convert.
*/
static void
default_number(krb5_context c, const char *opt, int defval, int *result)
{
char *tmp;
krb5_appdefault_string(c, "pam-afs-session", NULL, opt, "", &tmp);
if (tmp != NULL && tmp[0] != '\0')
*result = atoi(tmp);
else
*result = defval;
if (tmp != NULL)
free(tmp);
}
/*
* Load a boolean option from Kerberos appdefaults. This is a simple wrapper
* around the Kerberos library function.
*/
static void
default_boolean(krb5_context c, const char *opt, int defval, int *result)
{
krb5_appdefault_boolean(c, "pam-afs-session", NULL, opt, defval, result);
}
/*
* Load configuration options from krb5.conf. This is only done if we were
* built with Kerberos support. The list of options here should match the
* options we recognize in the PAM configuration.
*/
static void
load_krb5_config(struct pam_args *args)
{
krb5_context c;
krb5_error_code retval;
retval = krb5_init_context(&c);
if (retval != 0) {
pamafs_error_krb5(NULL, "cannot initialize Kerberos", retval);
return;
}
default_string(c, "afs_cells", NULL, &args->afs_cells);
default_boolean(c, "aklog_homedir", 0, &args->aklog_homedir);
default_boolean(c, "always_aklog", 0, &args->always_aklog);
default_boolean(c, "debug", 0, &args->debug);
default_boolean(c, "ignore_root", 0, &args->ignore_root);
default_boolean(c, "kdestroy", 0, &args->kdestroy);
default_number(c, "minimum_uid", 0, &args->minimum_uid);
default_boolean(c, "nopag", 0, &args->nopag);
default_boolean(c, "notokens", 0, &args->notokens);
default_string(c, "program", NULL, &args->program);
default_boolean(c, "retain_after_close", 0, &args->retain);
}
#endif /* HAVE_KERBEROS */
/*
* This is where we parse options. Currently, only setting options in the PAM
* arguments is supported. It would be nice to also support getting options
* from krb5.conf, but that requires linking with Kerberos libraries.
*/
struct pam_args *
pamafs_args_parse(int flags UNUSED, int argc, const char **argv)
{
struct pam_args *args;
int i;
args = pamafs_args_new();
if (args == NULL)
return NULL;
/*
* If we were built with Kerberos support, start by trying to load our
* configuration from krb5.conf. We want anything in the PAM
* configuration to override.
*/
#ifdef HAVE_KERBEROS
load_krb5_config(args);
#endif
for (i = 0; i < argc; i++) {
if (strncmp(argv[i], "afs_cells=", strlen("afs_cells=")) == 0) {
if (args->afs_cells != NULL)
free(args->afs_cells);
args->afs_cells = strdup(&argv[i][strlen("afs_cells=")]);
}
else if (strcmp(argv[i], "aklog_homedir") == 0)
args->aklog_homedir = 1;
else if (strcmp(argv[i], "always_aklog") == 0)
args->always_aklog = 1;
else if (strcmp(argv[i], "debug") == 0)
args->debug = 1;
else if (strcmp(argv[i], "ignore_root") == 0)
args->ignore_root = 1;
else if (strcmp(argv[i], "kdestroy") == 0)
args->kdestroy = 1;
else if (strncmp(argv[i], "minimum_uid=", 12) == 0)
args->minimum_uid = atoi(&argv[i][strlen("minimum_uid=")]);
else if (strcmp(argv[i], "nopag") == 0)
args->nopag = 1;
else if (strcmp(argv[i], "notokens") == 0)
args->notokens = 1;
else if (strncmp(argv[i], "program=", 8) == 0) {
if (args->program != NULL)
free(args->program);
args->program = strdup(&argv[i][strlen("program=")]);
}
else if (strcmp(argv[i], "retain_after_close") == 0)
args->retain = 1;
else
pamafs_error("unknown option %s", argv[i]);
}
#if defined(PATH_AKLOG) && !defined(HAVE_KRB5_AFSLOG)
if (args->program == NULL)
args->program = strdup(PATH_AKLOG);
#endif
/* Warn if kdestroy was set and we can't honor it. */
#ifndef HAVE_KERBEROS
if (args->kdestroy)
pamafs_error("kdestroy specified but not built with Kerberos support");
#endif
/*
* Turn afs_cells, which may be space and/or comma-separated, into a more
* useful null-terminated array of cells.
*/
if (args->afs_cells != NULL) {
size_t count, i;
char **new_cells;
char *p = args->afs_cells;
i = 0;
count = 2;
args->cells = malloc(count * sizeof(char *));
if (args->cells == NULL)
goto fail;
while (*p != '\0') {
while ((isspace((unsigned char) *p) || *p == ',') && *p != '\0') {
*p = '\0';
p++;
}
if (i >= count - 1) {
count++;
new_cells = realloc(args->cells, count * sizeof(char *));
if (new_cells == NULL)
goto fail;
args->cells = new_cells;
}
args->cells[i++] = p;
while (!isspace((unsigned char) *p) && *p != ',' && *p != '\0')
p++;
}
args->cells[i] = NULL;
args->cell_count = i;
}
return args;
fail:
pamafs_args_free(args);
return NULL;
}
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