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From d8ae33a302f01601e9e98b4aca3516e93c634a54 Mon Sep 17 00:00:00 2001
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From: Andreas Henriksson <andreas@fatal.se>
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Date: Sun, 14 Oct 2018 14:53:09 +0200
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Subject: [PATCH] sulogin-shell: Use force if SYSTEMD_SULOGIN_FORCE set
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When the root account is locked sulogin will either inform you of
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this and not allow you in or if --force is used it will hand
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you passwordless root (if using a recent enough version of util-linux).
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Not being allowed a shell is ofcourse inconvenient, but at the same
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time handing out passwordless root unconditionally is probably not
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a good idea everywhere.
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This patch thus allows to control which behaviour you want by
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setting the SYSTEMD_SULOGIN_FORCE environment variable to true
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or false to control the behaviour, eg. via adding this to
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'systemctl edit rescue.service' (or emergency.service):
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[Service]
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Environment=SYSTEMD_SULOGIN_FORCE=1
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Distributions who used locked root accounts and want the passwordless
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behaviour could thus simply drop in the override file in
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/etc/systemd/system/rescue.service.d/override.conf
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Fixes: #7115
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Addresses: https://bugs.debian.org/802211
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(cherry picked from commit 33eb44fe4a8d7971b5614bc4c2d90f8d91cce66c)
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Resolves: #1625929
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---
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 doc/ENVIRONMENT.md                |  6 ++++++
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 src/sulogin-shell/sulogin-shell.c | 11 ++++++++++-
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 2 files changed, 16 insertions(+), 1 deletion(-)
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diff --git a/doc/ENVIRONMENT.md b/doc/ENVIRONMENT.md
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index 1e648be640..39a36a52cc 100644
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--- a/doc/ENVIRONMENT.md
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+++ b/doc/ENVIRONMENT.md
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@@ -101,3 +101,9 @@ systemd-timedated:
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   NTP client services. If set, `timedatectl set-ntp on` enables and starts the
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   first existing unit listed in the environment variable, and
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   `timedatectl set-ntp off` disables and stops all listed units.
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+
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+systemd-sulogin-shell:
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+
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+* `$SYSTEMD_SULOGIN_FORCE=1` — This skips asking for the root password if the
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+  root password is not available (such as when the root account is locked).
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+  See `sulogin(8)` for more details.
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diff --git a/src/sulogin-shell/sulogin-shell.c b/src/sulogin-shell/sulogin-shell.c
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index 5db3592d6f..a1ea2333de 100644
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--- a/src/sulogin-shell/sulogin-shell.c
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+++ b/src/sulogin-shell/sulogin-shell.c
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@@ -9,6 +9,7 @@
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 #include "bus-util.h"
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 #include "bus-error.h"
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 #include "def.h"
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+#include "env-util.h"
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 #include "log.h"
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 #include "process-util.h"
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 #include "sd-bus.h"
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@@ -89,7 +90,11 @@ static void print_mode(const char* mode) {
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 }
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 int main(int argc, char *argv[]) {
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-        static const char* const sulogin_cmdline[] = {SULOGIN, NULL};
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+        const char* sulogin_cmdline[] = {
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+                SULOGIN,
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+                NULL,             /* --force */
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+                NULL
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+        };
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         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
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         int r;
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@@ -99,6 +104,10 @@ int main(int argc, char *argv[]) {
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         print_mode(argc > 1 ? argv[1] : "");
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+        if (getenv_bool("SYSTEMD_SULOGIN_FORCE") > 0)
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+                /* allows passwordless logins if root account is locked. */
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+                sulogin_cmdline[1] = "--force";
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+
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         (void) fork_wait(sulogin_cmdline);
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         r = bus_connect_system_systemd(&bus;;