1 files changed, 140 insertions, 0 deletions
diff --git a/src/home/pwquality-util.c b/src/home/pwquality-util.c
new file mode 100644
index 0000000000..c814c8f11e
--- /dev/null
+++ b/src/home/pwquality-util.c
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <unistd.h>
+
+#if HAVE_PWQUALITY
+/* pwquality.h uses size_t but doesn't include sys/types.h on its own */
+#include <sys/types.h>
+#include <pwquality.h>
+#endif
+
+#include "bus-common-errors.h"
+#include "home-util.h"
+#include "pwquality-util.h"
+#include "strv.h"
+
+#if HAVE_PWQUALITY
+DEFINE_TRIVIAL_CLEANUP_FUNC(pwquality_settings_t*, pwquality_free_settings);
+
+static void pwquality_maybe_disable_dictionary(
+                pwquality_settings_t *pwq) {
+
+        char buf[PWQ_MAX_ERROR_MESSAGE_LEN];
+        const char *path;
+        int r;
+
+        r = pwquality_get_str_value(pwq, PWQ_SETTING_DICT_PATH, &path);
+        if (r < 0) {
+                log_warning("Failed to read libpwquality dictionary path, ignoring: %s", pwquality_strerror(buf, sizeof(buf), r, NULL));
+                return;
+        }
+
+        // REMOVE THIS AS SOON AS https://github.com/libpwquality/libpwquality/pull/21 IS MERGED AND RELEASED
+        if (isempty(path))
+                path = "/usr/share/cracklib/pw_dict.pwd.gz";
+
+        if (isempty(path)) {
+                log_warning("Weird, no dictionary file configured, ignoring.");
+                return;
+        }
+
+        if (access(path, F_OK) >= 0)
+                return;
+
+        if (errno != ENOENT) {
+                log_warning_errno(errno, "Failed to check if dictionary file %s exists, ignoring: %m", path);
+                return;
+        }
+
+        r = pwquality_set_int_value(pwq, PWQ_SETTING_DICT_CHECK, 0);
+        if (r < 0) {
+                log_warning("Failed to disable libpwquality dictionary check, ignoring: %s", pwquality_strerror(buf, sizeof(buf), r, NULL));
+                return;
+        }
+}
+
+int quality_check_password(
+                UserRecord *hr,
+                UserRecord *secret,
+                sd_bus_error *error) {
+
+        _cleanup_(pwquality_free_settingsp) pwquality_settings_t *pwq = NULL;
+        char buf[PWQ_MAX_ERROR_MESSAGE_LEN], **pp;
+        void *auxerror;
+        int r;
+
+        assert(hr);
+        assert(secret);
+
+        pwq = pwquality_default_settings();
+        if (!pwq)
+                return log_oom();
+
+        r = pwquality_read_config(pwq, NULL, &auxerror);
+        if (r < 0)
+                log_warning_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to read libpwquality configuation, ignoring: %s",
+                                  pwquality_strerror(buf, sizeof(buf), r, auxerror));
+
+        pwquality_maybe_disable_dictionary(pwq);
+
+        /* This is a bit more complex than one might think at first. pwquality_check() would like to know the
+         * old password to make security checks. We support arbitrary numbers of passwords however, hence we
+         * call the function once for each combination of old and new password. */
+
+        /* Iterate through all new passwords */
+        STRV_FOREACH(pp, secret->password) {
+                bool called = false;
+                char **old;
+
+                r = test_password_many(hr->hashed_password, *pp);
+                if (r < 0)
+                        return r;
+                if (r == 0) /* This is an old password as it isn't listed in the hashedPassword field, skip it */
+                        continue;
+
+                /* Check this password against all old passwords */
+                STRV_FOREACH(old, secret->password) {
+
+                        if (streq(*pp, *old))
+                                continue;
+
+                        r = test_password_many(hr->hashed_password, *old);
+                        if (r < 0)
+                                return r;
+                        if (r > 0) /* This is a new password, not suitable as old password */
+                                continue;
+
+                        r = pwquality_check(pwq, *pp, *old, hr->user_name, &auxerror);
+                        if (r < 0)
+                                return sd_bus_error_setf(error, BUS_ERROR_LOW_PASSWORD_QUALITY, "Password too weak: %s",
+                                                         pwquality_strerror(buf, sizeof(buf), r, auxerror));
+
+                        called = true;
+                }
+
+                if (called)
+                        continue;
+
+                /* If there are no old passwords, let's call pwquality_check() without any. */
+                r = pwquality_check(pwq, *pp, NULL, hr->user_name, &auxerror);
+                if (r < 0)
+                        return sd_bus_error_setf(error, BUS_ERROR_LOW_PASSWORD_QUALITY, "Password too weak: %s",
+                                                 pwquality_strerror(buf, sizeof(buf), r, auxerror));
+        }
+
+        return 0;
+}
+
+#else
+
+int quality_check_password(
+                UserRecord *hr,
+                UserRecord *secret,
+                sd_bus_error *error) {
+
+        assert(hr);
+        assert(secret);
+
+        return 0;
+}
+#endif