Merge pull request #19411 from poettering/homectl-fixes

homectl password caching fixes

src/basic/user-util.c

@@ -1072,3 +1072,16 @@ int fgetsgent_sane(FILE *stream, struct sgrp **sg) {
         return !!s;
 }
 #endif
+
+int is_this_me(const char *username) {
+        uid_t uid;
+        int r;
+
+        /* Checks if the specified username is our current one. Passed string might be a UID or a user name. */
+
+        r = get_user_creds(&username, &uid, NULL, NULL, NULL, USER_CREDS_ALLOW_MISSING);
+        if (r < 0)
+                return r;
+
+        return uid == getuid();
+}

src/basic/user-util.h

@@ -109,3 +109,5 @@ int putsgent_sane(const struct sgrp *sg, FILE *stream);
 #endif
 
 bool is_nologin_shell(const char *shell);
+
+int is_this_me(const char *username);

src/home/homectl.c

@@ -190,7 +190,12 @@ static int list_homes(int argc, char *argv[], void *userdata) {
         return 0;
 }
 
-static int acquire_existing_password(const char *user_name, UserRecord *hr, bool emphasize_current) {
+static int acquire_existing_password(
+                const char *user_name,
+                UserRecord *hr,
+                bool emphasize_current,
+                AskPasswordFlags flags) {
+
         _cleanup_(strv_free_erasep) char **password = NULL;
         _cleanup_free_ char *question = NULL;
         char *e;
@@ -212,16 +217,32 @@ static int acquire_existing_password(const char *user_name, UserRecord *hr, bool
                 string_erase(e);
                 assert_se(unsetenv("PASSWORD") == 0);
 
-                return 0;
+                return 1;
         }
 
+        /* If this is not our own user, then don't use the password cache */
+        if (is_this_me(user_name) <= 0)
+                SET_FLAG(flags, ASK_PASSWORD_ACCEPT_CACHED|ASK_PASSWORD_PUSH_CACHE, false);
+
         if (asprintf(&question, emphasize_current ?
                      "Please enter current password for user %s:" :
                      "Please enter password for user %s:",
                      user_name) < 0)
                 return log_oom();
 
-        r = ask_password_auto(question, "user-home", NULL, "home-password", "home.password", USEC_INFINITY, ASK_PASSWORD_ACCEPT_CACHED|ASK_PASSWORD_PUSH_CACHE, &password);
+        r = ask_password_auto(question,
+                              /* icon= */ "user-home",
+                              NULL,
+                              /* key_name= */ "home-password",
+                              /* credential_name= */ "home.password",
+                              USEC_INFINITY,
+                              flags,
+                              &password);
+        if (r == -EUNATCH) { /* EUNATCH is returned if no password was found and asking interactively was
+                              * disabled via the flags. Not an error for us. */
+                log_debug_errno(r, "No passwords acquired.");
+                return 0;
+        }
         if (r < 0)
                 return log_error_errno(r, "Failed to acquire password: %m");
 
@@ -229,10 +250,14 @@ static int acquire_existing_password(const char *user_name, UserRecord *hr, bool
         if (r < 0)
                 return log_error_errno(r, "Failed to store password: %m");
 
-        return 0;
+        return 1;
 }
 
-static int acquire_token_pin(const char *user_name, UserRecord *hr) {
+static int acquire_token_pin(
+                const char *user_name,
+                UserRecord *hr,
+                AskPasswordFlags flags) {
+
         _cleanup_(strv_free_erasep) char **pin = NULL;
         _cleanup_free_ char *question = NULL;
         char *e;
@@ -250,14 +275,30 @@ static int acquire_token_pin(const char *user_name, UserRecord *hr) {
                 string_erase(e);
                 assert_se(unsetenv("PIN") == 0);
 
-                return 0;
+                return 1;
         }
 
+        /* If this is not our own user, then don't use the password cache */
+        if (is_this_me(user_name) <= 0)
+                SET_FLAG(flags, ASK_PASSWORD_ACCEPT_CACHED|ASK_PASSWORD_PUSH_CACHE, false);
+
         if (asprintf(&question, "Please enter security token PIN for user %s:", user_name) < 0)
                 return log_oom();
 
-        /* We never cache or use cached PINs, since usually there are only very few attempts allowed before the PIN is blocked */
+        r = ask_password_auto(
-        r = ask_password_auto(question, "user-home", NULL, "token-pin", "home.token-pin", USEC_INFINITY, 0, &pin);
+                        question,
+                        /* icon= */ "user-home",
+                        NULL,
+                        /* key_name= */ "token-pin",
+                        /* credential_name= */ "home.token-pin",
+                        USEC_INFINITY,
+                        flags,
+                        &pin);
+        if (r == -EUNATCH) { /* EUNATCH is returned if no PIN was found and asking interactively was disabled
+                              * via the flags. Not an error for us. */
+                log_debug_errno(r, "No security token PINs acquired.");
+                return 0;
+        }
         if (r < 0)
                 return log_error_errno(r, "Failed to acquire security token PIN: %m");
 
@@ -265,7 +306,7 @@ static int acquire_token_pin(const char *user_name, UserRecord *hr) {
         if (r < 0)
                 return log_error_errno(r, "Failed to store security token PIN: %m");
 
-        return 0;
+        return 1;
 }
 
 static int handle_generic_user_record_error(
@@ -292,7 +333,13 @@ static int handle_generic_user_record_error(
                 if (!strv_isempty(hr->password))
                         log_notice("Password incorrect or not sufficient, please try again.");
 
-                r = acquire_existing_password(user_name, hr, emphasize_current_password);
+                /* Don't consume cache entries or credentials here, we already tried that unsuccessfully. But
+                 * let's push what we acquire here into the cache */
+                r = acquire_existing_password(
+                                user_name,
+                                hr,
+                                emphasize_current_password,
+                                ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_NO_CREDENTIAL);
                 if (r < 0)
                         return r;
 
@@ -303,13 +350,21 @@ static int handle_generic_user_record_error(
                 else
                         log_notice("Password incorrect or not sufficient, and configured security token not inserted, please try again.");
 
-                r = acquire_existing_password(user_name, hr, emphasize_current_password);
+                r = acquire_existing_password(
+                                user_name,
+                                hr,
+                                emphasize_current_password,
+                                ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_NO_CREDENTIAL);
                 if (r < 0)
                         return r;
 
         } else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PIN_NEEDED)) {
 
-                r = acquire_token_pin(user_name, hr);
+                /* First time the PIN is requested, let's accept cached data, and allow using credential store */
+                r = acquire_token_pin(
+                                user_name,
+                                hr,
+                                ASK_PASSWORD_ACCEPT_CACHED | ASK_PASSWORD_PUSH_CACHE);
                 if (r < 0)
                         return r;
 
@@ -340,7 +395,11 @@ static int handle_generic_user_record_error(
 
                 log_notice("Security token PIN incorrect, please try again.");
 
-                r = acquire_token_pin(user_name, hr);
+                /* If the previous PIN was wrong don't accept cached info anymore, but add to cache. Also, don't use the credential data */
+                r = acquire_token_pin(
+                                user_name,
+                                hr,
+                                ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_NO_CREDENTIAL);
                 if (r < 0)
                         return r;
 
@@ -348,7 +407,10 @@ static int handle_generic_user_record_error(
 
                 log_notice("Security token PIN incorrect, please try again (only a few tries left!).");
 
-                r = acquire_token_pin(user_name, hr);
+                r = acquire_token_pin(
+                                user_name,
+                                hr,
+                                ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_NO_CREDENTIAL);
                 if (r < 0)
                         return r;
 
@@ -356,7 +418,10 @@ static int handle_generic_user_record_error(
 
                 log_notice("Security token PIN incorrect, please try again (only one try left!).");
 
-                r = acquire_token_pin(user_name, hr);
+                r = acquire_token_pin(
+                                user_name,
+                                hr,
+                                ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_NO_CREDENTIAL);
                 if (r < 0)
                         return r;
         } else
@@ -365,6 +430,39 @@ static int handle_generic_user_record_error(
         return 0;
 }
 
+static int acquire_passed_secrets(const char *user_name, UserRecord **ret) {
+        _cleanup_(user_record_unrefp) UserRecord *secret = NULL;
+        int r;
+
+        assert(ret);
+
+        /* Generates an initial secret objects that contains passwords supplied via $PASSWORD, the password
+         * cache or the credentials subsystem, but excluding any interactive stuff. If nothing is passed,
+         * returns an empty secret object. */
+
+        secret = user_record_new();
+        if (!secret)
+                return log_oom();
+
+        r = acquire_existing_password(
+                        user_name,
+                        secret,
+                        /* emphasize_current_password = */ false,
+                        ASK_PASSWORD_ACCEPT_CACHED | ASK_PASSWORD_NO_TTY | ASK_PASSWORD_NO_AGENT);
+        if (r < 0)
+                return r;
+
+        r = acquire_token_pin(
+                        user_name,
+                        secret,
+                        ASK_PASSWORD_ACCEPT_CACHED | ASK_PASSWORD_NO_TTY | ASK_PASSWORD_NO_AGENT);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(secret);
+        return 0;
+}
+
 static int activate_home(int argc, char *argv[], void *userdata) {
         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
         int r, ret = 0;
@@ -377,9 +475,9 @@ static int activate_home(int argc, char *argv[], void *userdata) {
         STRV_FOREACH(i, strv_skip(argv, 1)) {
                 _cleanup_(user_record_unrefp) UserRecord *secret = NULL;
 
-                secret = user_record_new();
+                r = acquire_passed_secrets(*i, &secret);
-                if (!secret)
+                if (r < 0)
-                        return log_oom();
+                        return r;
 
                 for (;;) {
                         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@@ -399,7 +497,7 @@ static int activate_home(int argc, char *argv[], void *userdata) {
 
                         r = sd_bus_call(bus, m, HOME_SLOW_BUS_CALL_TIMEOUT_USEC, &error, NULL);
                         if (r < 0) {
-                                r = handle_generic_user_record_error(*i, secret, &error, r, false);
+                                r = handle_generic_user_record_error(*i, secret, &error, r, /* emphasize_current_password= */ false);
                                 if (r < 0) {
                                         if (ret == 0)
                                                 ret = r;
@@ -603,9 +701,9 @@ static int authenticate_home(int argc, char *argv[], void *userdata) {
         STRV_FOREACH(i, items) {
                 _cleanup_(user_record_unrefp) UserRecord *secret = NULL;
 
-                secret = user_record_new();
+                r = acquire_passed_secrets(*i, &secret);
-                if (!secret)
+                if (r < 0)
-                        return log_oom();
+                        return r;
 
                 for (;;) {
                         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@@ -1010,7 +1108,15 @@ static int acquire_new_password(
                 if (asprintf(&question, "Please enter new password for user %s:", user_name) < 0)
                         return log_oom();
 
-                r = ask_password_auto(question, "user-home", NULL, "home-password", "home.new-password", USEC_INFINITY, 0, &first);
+                r = ask_password_auto(
+                                question,
+                                /* icon= */ "user-home",
+                                NULL,
+                                /* key_name= */ "home-password",
+                                /* credential_name= */ "home.new-password",
+                                USEC_INFINITY,
+                                0, /* no caching, we want to collect a new password here after all */
+                                &first);
                 if (r < 0)
                         return log_error_errno(r, "Failed to acquire password: %m");
 
@@ -1018,7 +1124,15 @@ static int acquire_new_password(
                 if (asprintf(&question, "Please enter new password for user %s (repeat):", user_name) < 0)
                         return log_oom();
 
-                r = ask_password_auto(question, "user-home", NULL, "home-password", "home.new-password", USEC_INFINITY, 0, &second);
+                r = ask_password_auto(
+                                question,
+                                /* icon= */ "user-home",
+                                NULL,
+                                /* key_name= */ "home-password",
+                                /* credential_name= */ "home.new-password",
+                                USEC_INFINITY,
+                                0, /* no caching */
+                                &second);
                 if (r < 0)
                         return log_error_errno(r, "Failed to acquire password: %m");
 
@@ -1106,7 +1220,11 @@ static int create_home(int argc, char *argv[], void *userdata) {
                                 return log_error_errno(r, "Failed to hash password: %m");
                 } else {
                         /* There's a hash password set in the record, acquire the unhashed version of it. */
-                        r = acquire_existing_password(hr->user_name, hr, /* emphasize_current= */ false);
+                        r = acquire_existing_password(
+                                        hr->user_name,
+                                        hr,
+                                        /* emphasize_current= */ false,
+                                        ASK_PASSWORD_ACCEPT_CACHED | ASK_PASSWORD_PUSH_CACHE);
                         if (r < 0)
                                 return r;
                 }
@@ -1585,9 +1703,9 @@ static int resize_home(int argc, char *argv[], void *userdata) {
                 ds = arg_disk_size;
         }
 
-        secret = user_record_new();
+        r = acquire_passed_secrets(argv[1], &secret);
-        if (!secret)
+        if (r < 0)
-                return log_oom();
+                return r;
 
         for (;;) {
                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@@ -1661,9 +1779,9 @@ static int unlock_home(int argc, char *argv[], void *userdata) {
         STRV_FOREACH(i, strv_skip(argv, 1)) {
                 _cleanup_(user_record_unrefp) UserRecord *secret = NULL;
 
-                secret = user_record_new();
+                r = acquire_passed_secrets(*i, &secret);
-                if (!secret)
+                if (r < 0)
-                        return log_oom();
+                        return r;
 
                 for (;;) {
                         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@@ -1727,9 +1845,9 @@ static int with_home(int argc, char *argv[], void *userdata) {
         if (!cmdline)
                 return log_oom();
 
-        secret = user_record_new();
+        r = acquire_passed_secrets(argv[1], &secret);
-        if (!secret)
+        if (r < 0)
-                return log_oom();
+                return r;
 
         for (;;) {
                 r = bus_message_new_method_call(bus, &m, bus_mgr, "AcquireHome");