systemd/SOURCES/0670-boot-remove-random-seed-mode.patch

From 44f9f0e2e416b67c2ca46e9e36184f4a0bf1f1b0 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 21 Nov 2022 16:40:24 +0100
Subject: [PATCH] boot: remove random-seed-mode

Now that the random seed is used on virtualized systems, there's no
point in having a random-seed-mode toggle switch. Let's just always
require it now, with the existing logic already being there to allow not
having it if EFI itself has an RNG. In other words, the logic for this
can now be automatic.

(cherry picked from commit 47b3e96647e18e8ca219c4792ab769344eea11bb)

Related: RHEL-16952
---
 docs/RANDOM_SEEDS.md       |  8 --------
 man/loader.conf.xml        | 19 -------------------
 src/boot/efi/boot.c        | 26 +-------------------------
 src/boot/efi/random-seed.c |  5 +----
 src/boot/efi/random-seed.h | 18 +-----------------
 src/shared/bootspec.c      |  3 +--
 src/shared/bootspec.h      |  1 -
 7 files changed, 4 insertions(+), 76 deletions(-)

diff --git a/docs/RANDOM_SEEDS.md b/docs/RANDOM_SEEDS.md
index a1134d6417..4cb2bb9cfa 100644
--- a/docs/RANDOM_SEEDS.md
+++ b/docs/RANDOM_SEEDS.md
@@ -232,14 +232,6 @@ boot, in order to ensure the entropy pool is filled up quickly.
    too), which should be safe even with FAT file system drivers built into
    low-quality EFI firmwares.
 
-   If the system token is not desired but this seeding mechanism still is, OS
-   builders that know that they are not going to replicate the built image on
-   multiple systems may opt to turn off the 'system token' concept by setting
-   `random-seed-mode always` in the ESP's
-   [`/loader/loader.conf`](https://www.freedesktop.org/software/systemd/man/loader.conf.html)
-   file. If done, `systemd-boot` will use the random seed file even if no
-   system token is found in EFI variables.
-
 4. A kernel command line option `systemd.random_seed=` may be used to pass in a
    base64 encoded seed to initialize the kernel's entropy pool from during
    early service manager initialization. This option is only safe in testing
diff --git a/man/loader.conf.xml b/man/loader.conf.xml
index 7f173aec61..d937583da9 100644
--- a/man/loader.conf.xml
+++ b/man/loader.conf.xml
@@ -309,25 +309,6 @@ sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl db.auth
         encrypted drive to change. If PCR 4 is not measured, this setting can be disabled to speed
         up booting into Windows.</para></listitem>
       </varlistentry>
-
-      <varlistentry>
-        <term>random-seed-mode</term>
-
-        <listitem><para>Takes one of <literal>off</literal>, <literal>with-system-token</literal> and
-        <literal>always</literal>. If <literal>off</literal> no random seed data is read off the ESP, nor
-        passed to the OS. If <literal>with-system-token</literal> (the default)
-        <command>systemd-boot</command> will read a random seed from the ESP (from the file
-        <filename>/loader/random-seed</filename>) only if the <varname>LoaderSystemToken</varname> EFI
-        variable is set, and then derive the random seed to pass to the OS from the combination. If
-        <literal>always</literal> the boot loader will do so even if <varname>LoaderSystemToken</varname> is
-        not set. This mode is useful in environments where protection against OS image reuse is not a
-        concern, and the random seed shall be used even with no further setup in place. Use <command>bootctl
-        random-seed</command> to initialize both the random seed file in the ESP and the system token EFI
-        variable.</para>
-
-        <para>See <ulink url="https://systemd.io/RANDOM_SEEDS">Random Seeds</ulink> for further
-        information.</para></listitem>
-      </varlistentry>
     </variablelist>
   </refsect1>
 
diff --git a/src/boot/efi/boot.c b/src/boot/efi/boot.c
index 5944451e6a..4a64c2402d 100644
--- a/src/boot/efi/boot.c
+++ b/src/boot/efi/boot.c
@@ -97,7 +97,6 @@ typedef struct {
         bool beep;
         int64_t console_mode;
         int64_t console_mode_efivar;
-        RandomSeedMode random_seed_mode;
 } Config;
 
 /* These values have been chosen so that the transitions the user sees could
@@ -529,7 +528,6 @@ static void print_status(Config *config, char16_t *loaded_image_path) {
           ps_bool(L"         auto-firmware: %s\n", config->auto_firmware);
           ps_bool(L"                  beep: %s\n", config->beep);
           ps_bool(L"  reboot-for-bitlocker: %s\n", config->reboot_for_bitlocker);
-        ps_string(L"      random-seed-mode: %s\n", random_seed_modes_table[config->random_seed_mode]);
 
         switch (config->secure_boot_enroll) {
         case ENROLL_OFF:
@@ -1273,27 +1271,6 @@ static void config_defaults_load_from_file(Config *config, char *content) {
                         }
                         continue;
                 }
-
-                if (streq8(key, "random-seed-mode")) {
-                        if (streq8(value, "off"))
-                                config->random_seed_mode = RANDOM_SEED_OFF;
-                        else if (streq8(value, "with-system-token"))
-                                config->random_seed_mode = RANDOM_SEED_WITH_SYSTEM_TOKEN;
-                        else if (streq8(value, "always"))
-                                config->random_seed_mode = RANDOM_SEED_ALWAYS;
-                        else {
-                                bool on;
-
-                                err = parse_boolean(value, &on);
-                                if (err != EFI_SUCCESS) {
-                                        log_error_stall(L"Error parsing 'random-seed-mode' config option: %a", value);
-                                        continue;
-                                }
-
-                                config->random_seed_mode = on ? RANDOM_SEED_ALWAYS : RANDOM_SEED_OFF;
-                        }
-                        continue;
-                }
         }
 }
 
@@ -1584,7 +1561,6 @@ static void config_load_defaults(Config *config, EFI_FILE *root_dir) {
                 .auto_firmware = true,
                 .reboot_for_bitlocker = false,
                 .secure_boot_enroll = ENROLL_MANUAL,
-                .random_seed_mode = RANDOM_SEED_WITH_SYSTEM_TOKEN,
                 .idx_default_efivar = IDX_INVALID,
                 .console_mode = CONSOLE_MODE_KEEP,
                 .console_mode_efivar = CONSOLE_MODE_KEEP,
@@ -2735,7 +2711,7 @@ EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *sys_table) {
                 save_selected_entry(&config, entry);
 
                 /* Optionally, read a random seed off the ESP and pass it to the OS */
-                (void) process_random_seed(root_dir, config.random_seed_mode);
+                (void) process_random_seed(root_dir);
 
                 err = image_start(image, entry);
                 if (err != EFI_SUCCESS)
diff --git a/src/boot/efi/random-seed.c b/src/boot/efi/random-seed.c
index 471398fbf1..4fc56d9356 100644
--- a/src/boot/efi/random-seed.c
+++ b/src/boot/efi/random-seed.c
@@ -140,9 +140,6 @@ EFI_STATUS process_random_seed(EFI_FILE *root_dir) {
 
         validate_sha256();
 
-        if (mode == RANDOM_SEED_OFF)
-                return EFI_NOT_FOUND;
-
         /* hash = LABEL || sizeof(input1) || input1 || ... || sizeof(inputN) || inputN */
         sha256_init_ctx(&hash);
 
@@ -193,7 +190,7 @@ EFI_STATUS process_random_seed(EFI_FILE *root_dir) {
          * system, even when disk images are duplicated or swapped out. */
         size = 0;
         err = acquire_system_token(&system_token, &size);
-        if (mode != RANDOM_SEED_ALWAYS && (err != EFI_SUCCESS || size < DESIRED_SEED_SIZE) && !seeded_by_efi)
+        if ((err != EFI_SUCCESS || size < DESIRED_SEED_SIZE) && !seeded_by_efi)
                 return err;
         sha256_process_bytes(&size, sizeof(size), &hash);
         if (system_token) {
diff --git a/src/boot/efi/random-seed.h b/src/boot/efi/random-seed.h
index 6aa1cc5288..40aaf85860 100644
--- a/src/boot/efi/random-seed.h
+++ b/src/boot/efi/random-seed.h
@@ -2,21 +2,5 @@
 #pragma once
 
 #include <efi.h>
-#include <errno.h>
-#include <uchar.h>
 
-typedef enum RandomSeedMode {
-        RANDOM_SEED_OFF,
-        RANDOM_SEED_WITH_SYSTEM_TOKEN,
-        RANDOM_SEED_ALWAYS,
-        _RANDOM_SEED_MODE_MAX,
-        _RANDOM_SEED_MODE_INVALID = -EINVAL,
-} RandomSeedMode;
-
-static const char16_t * const random_seed_modes_table[_RANDOM_SEED_MODE_MAX] = {
-        [RANDOM_SEED_OFF]               = L"off",
-        [RANDOM_SEED_WITH_SYSTEM_TOKEN] = L"with-system-token",
-        [RANDOM_SEED_ALWAYS]            = L"always",
-};
-
-EFI_STATUS process_random_seed(EFI_FILE *root_dir, RandomSeedMode mode);
+EFI_STATUS process_random_seed(EFI_FILE *root_dir);
diff --git a/src/shared/bootspec.c b/src/shared/bootspec.c
index 9352416af5..61e20c40a8 100644
--- a/src/shared/bootspec.c
+++ b/src/shared/bootspec.c
@@ -418,7 +418,6 @@ void boot_config_free(BootConfig *config) {
         free(config->auto_entries);
         free(config->auto_firmware);
         free(config->console_mode);
-        free(config->random_seed_mode);
         free(config->beep);
 
         free(config->entry_oneshot);
@@ -485,7 +484,7 @@ int boot_loader_read_conf(BootConfig *config, FILE *file, const char *path) {
                 else if (streq(field, "console-mode"))
                         r = free_and_strdup(&config->console_mode, p);
                 else if (streq(field, "random-seed-mode"))
-                        r = free_and_strdup(&config->random_seed_mode, p);
+                        log_syntax(NULL, LOG_WARNING, path, line, 0, "'random-seed-mode' has been deprecated, ignoring.");
                 else if (streq(field, "beep"))
                         r = free_and_strdup(&config->beep, p);
                 else {
diff --git a/src/shared/bootspec.h b/src/shared/bootspec.h
index 7f5d496b95..ac4d1890b0 100644
--- a/src/shared/bootspec.h
+++ b/src/shared/bootspec.h
@@ -57,7 +57,6 @@ typedef struct BootConfig {
         char *auto_entries;
         char *auto_firmware;
         char *console_mode;
-        char *random_seed_mode;
         char *beep;
 
         char *entry_oneshot;