pam_pwhistory: load config from file

* modules/pam_pwhistory/pam_pwhistory.c: Load config from file and
provide new conf option to select the file.
* modules/pam_pwhistory/pwhistory_config.c: Parse config from file and
load to options structure.
* modules/pam_pwhistory/pwhistory_config.h: Move options_t structure and
define parse_config_file().
* modules/pam_pwhistory/Makefile.am (noinst_HEADERS): Add pwhistory_config.h.
(pam_pwhistory_la_SOURCES): Add pwhistory_config.c.
(dist_secureconf_DATA): Add pwhistory.conf.
* modules/pam_pwhistory/pwhistory.conf: New configuration file.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2068461

Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>

5 files changed, 197 insertions, 11 deletions

diff --git a/modules/pam_pwhistory/Makefile.am b/modules/pam_pwhistory/Makefile.am
index 8a4dbcb2..a50fdc74 100644
--- a/modules/pam_pwhistory/Makefile.am
+++ b/modules/pam_pwhistory/Makefile.am
@@ -26,12 +26,14 @@ if HAVE_VERSIONING
   pam_pwhistory_la_LDFLAGS += -Wl,--version-script=$(srcdir)/../modules.map
 endif
 
-noinst_HEADERS = opasswd.h
+noinst_HEADERS = opasswd.h pwhistory_config.h
+
+dist_secureconf_DATA = pwhistory.conf
 
 securelib_LTLIBRARIES = pam_pwhistory.la
 pam_pwhistory_la_CFLAGS = $(AM_CFLAGS)
 pam_pwhistory_la_LIBADD = $(top_builddir)/libpam/libpam.la @LIBCRYPT@ @LIBSELINUX@
-pam_pwhistory_la_SOURCES = pam_pwhistory.c opasswd.c
+pam_pwhistory_la_SOURCES = pam_pwhistory.c opasswd.c pwhistory_config.c
 
 sbin_PROGRAMS = pwhistory_helper
 pwhistory_helper_CFLAGS = $(AM_CFLAGS) -DHELPER_COMPILE=\"pwhistory_helper\" @EXE_CFLAGS@
diff --git a/modules/pam_pwhistory/pam_pwhistory.c b/modules/pam_pwhistory/pam_pwhistory.c
index 9c1bdd87..5a7fb811 100644
--- a/modules/pam_pwhistory/pam_pwhistory.c
+++ b/modules/pam_pwhistory/pam_pwhistory.c
@@ -63,15 +63,8 @@
 
 #include "opasswd.h"
 #include "pam_inline.h"
+#include "pwhistory_config.h"
 
-struct options_t {
-  int debug;
-  int enforce_for_root;
-  int remember;
-  int tries;
-  const char *filename;
-};
-typedef struct options_t options_t;
 
 
 static void
@@ -312,6 +305,8 @@ pam_sm_chauthtok (pam_handle_t *pamh, int flags, int argc, const char **argv)
   options.remember = 10;
   options.tries = 1;
 
+  parse_config_file(pamh, argc, argv, &options);
+
   /* Parse parameters for module */
   for ( ; argc-- > 0; argv++)
     parse_option (pamh, *argv, &options);
@@ -319,7 +314,6 @@ pam_sm_chauthtok (pam_handle_t *pamh, int flags, int argc, const char **argv)
   if (options.debug)
     pam_syslog (pamh, LOG_DEBUG, "pam_sm_chauthtok entered");
 
-
   if (options.remember == 0)
     return PAM_IGNORE;
 
diff --git a/modules/pam_pwhistory/pwhistory.conf b/modules/pam_pwhistory/pwhistory.conf
new file mode 100644
index 00000000..070b7197
--- /dev/null
+++ b/modules/pam_pwhistory/pwhistory.conf
@@ -0,0 +1,21 @@
+# Configuration for remembering the last passwords used by a user.
+#
+# Enable the debugging logs.
+# Enabled if option is present.
+# debug
+#
+# root account's passwords are also remembered.
+# Enabled if option is present.
+# enforce_for_root
+#
+# Number of passwords to remember.
+# The default is 10.
+# remember = 10
+#
+# Number of times to prompt for the password.
+# The default is 1.
+# retry = 1
+#
+# The directory where the last passwords are kept.
+# The default is /etc/security/opasswd.
+# file = /etc/security/opasswd
diff --git a/modules/pam_pwhistory/pwhistory_config.c b/modules/pam_pwhistory/pwhistory_config.c
new file mode 100644
index 00000000..b21879c6
--- /dev/null
+++ b/modules/pam_pwhistory/pwhistory_config.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2022 Iker Pedrosa <ipedrosa@redhat.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions.  (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+
+#include <security/pam_modutil.h>
+
+#include "pam_inline.h"
+#include "pwhistory_config.h"
+
+#define PWHISTORY_DEFAULT_CONF SCONFIGDIR "/pwhistory.conf"
+
+void
+parse_config_file(pam_handle_t *pamh, int argc, const char **argv,
+                  struct options_t *options)
+{
+    const char *fname = NULL;
+    int i;
+    char *val;
+
+    for (i = 0; i < argc; ++i) {
+        const char *str = pam_str_skip_prefix(argv[i], "conf=");
+
+        if (str != NULL) {
+            fname = str;
+        }
+    }
+
+    if (fname == NULL) {
+        fname = PWHISTORY_DEFAULT_CONF;
+    }
+
+    val = pam_modutil_search_key (pamh, fname, "debug");
+    if (val != NULL) {
+        options->debug = 1;
+        free(val);
+    }
+
+    val = pam_modutil_search_key (pamh, fname, "enforce_for_root");
+    if (val != NULL) {
+        options->enforce_for_root = 1;
+        free(val);
+    }
+
+    val = pam_modutil_search_key (pamh, fname, "remember");
+    if (val != NULL) {
+        unsigned int temp;
+        if (sscanf(val, "%u", &temp) != 1) {
+            pam_syslog(pamh, LOG_ERR,
+                "Bad number supplied for remember argument");
+        } else {
+            options->remember = temp;
+        }
+        free(val);
+    }
+
+    val = pam_modutil_search_key (pamh, fname, "retry");
+    if (val != NULL) {
+        unsigned int temp;
+        if (sscanf(val, "%u", &temp) != 1) {
+            pam_syslog(pamh, LOG_ERR,
+                "Bad number supplied for retry argument");
+        } else {
+            options->tries = temp;
+        }
+        free(val);
+    }
+
+    val = pam_modutil_search_key (pamh, fname, "file");
+    if (val != NULL) {
+        if (*val != '/') {
+            pam_syslog (pamh, LOG_ERR,
+                "File path should be absolute: %s", val);
+        } else {
+            options->filename = val;
+        }
+    }
+}
diff --git a/modules/pam_pwhistory/pwhistory_config.h b/modules/pam_pwhistory/pwhistory_config.h
new file mode 100644
index 00000000..e2b3bc83
--- /dev/null
+++ b/modules/pam_pwhistory/pwhistory_config.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2022 Iker Pedrosa <ipedrosa@redhat.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions.  (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _PWHISTORY_CONFIG_H
+#define _PWHISTORY_CONFIG_H
+
+#include <security/pam_ext.h>
+
+struct options_t {
+    int debug;
+    int enforce_for_root;
+    int remember;
+    int tries;
+    const char *filename;
+};
+typedef struct options_t options_t;
+
+void
+parse_config_file(pam_handle_t *pamh, int argc, const char **argv,
+                  struct options_t *options);
+
+#endif /* _PWHISTORY_CONFIG_H */