From: Zbigniew Jędrzejewski-Szmek Date: Mon, 3 Oct 2022 10:12:15 +0000 (+0200) Subject: firstboot: process the root account after sysusers created it X-Git-Tag: v254-rc1~411^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F27750%2Fhead;p=thirdparty%2Fsystemd.git firstboot: process the root account after sysusers created it We would create root account from sysusers or from firstboot, depending on which one ran earlier. Since firstboot offers more options, in particular can set the root password, we needed to order it earlier. This created an ugly ordering requirement: systemd-sysusers.service > systemd-firstboot.service > ... > systemd-remount-fs.service > systemd-tmpfiles-setup-dev.service > systemd-sysusers.service We want sysusers.service to create basic users, so we can create nodes in dev, so we can operate on block devices and such, so that we can resize and remount things. But at the same time, systemd-firstboot.service can only work if it is run early, before systemd-sysusers.service has created /etc/passwd. We can't have it both ways: the units that want to have a fully writable root file system cannot be ordered before units which are required to do file system preparation. Instead of trying to order firstboot very early, let's let it do its thing even if it is started later. Instead of refusing to create to the root account if /etc/passwd and /etc/shadow exist, actually check if the account is configured. Now sysusers writes root account with password PASSWORD_UNPROVISIONED ("!unprovisioned"), and then firstboot checks for this, and will configure root in this case. This allows sysusers to be executed earlier (or accounts to be set up earlier in another way). This effectively reverts b825ab1a99b69956057c79838faaf7b44afee474. --- diff --git a/src/basic/user-util.h b/src/basic/user-util.h index 5aca6307e05..c82941dd814 100644 --- a/src/basic/user-util.h +++ b/src/basic/user-util.h @@ -150,3 +150,8 @@ static inline bool hashed_password_is_locked_or_invalid(const char *password) { /* A password indicating "hey, no password required for login" */ #define PASSWORD_NONE "" + +/* Used by sysusers to indicate that the password should be filled in by firstboot. + * Also see https://github.com/systemd/systemd/pull/24680#pullrequestreview-1439464325. + */ +#define PASSWORD_UNPROVISIONED "!unprovisioned" diff --git a/src/firstboot/firstboot.c b/src/firstboot/firstboot.c index 19d5568854e..6b42e640433 100644 --- a/src/firstboot/firstboot.c +++ b/src/firstboot/firstboot.c @@ -234,17 +234,72 @@ static int prompt_loop(const char *text, char **l, unsigned percentage, bool (*i } static int should_configure(int dir_fd, const char *filename) { + _cleanup_fclose_ FILE *passwd = NULL, *shadow = NULL; + int r; + assert(dir_fd >= 0); assert(filename); - if (faccessat(dir_fd, filename, F_OK, AT_SYMLINK_NOFOLLOW) < 0) { - if (errno != ENOENT) - return log_error_errno(errno, "Failed to access %s: %m", filename); + if (streq(filename, "passwd") && !arg_force) + /* We may need to do additional checks, so open the file. */ + r = xfopenat(dir_fd, filename, "re", O_NOFOLLOW, &passwd); + else + r = RET_NERRNO(faccessat(dir_fd, filename, F_OK, AT_SYMLINK_NOFOLLOW)); + if (r == -ENOENT) return true; /* missing */ + if (r < 0) + return log_error_errno(r, "Failed to access %s: %m", filename); + if (arg_force) + return true; /* exists, but if --force was given we should still configure the file. */ + + if (!passwd) + return false; + + /* In case of /etc/passwd, do an additional check for the root password field. + * We first check that passwd redirects to shadow, and then we check shadow. + */ + struct passwd *i; + while ((r = fgetpwent_sane(passwd, &i)) > 0) { + if (!streq(i->pw_name, "root")) + continue; + + if (streq_ptr(i->pw_passwd, PASSWORD_SEE_SHADOW)) + break; + log_debug("passwd: root account with non-shadow password found, treating root as configured"); + return false; } + if (r < 0) + return log_error_errno(r, "Failed to read %s: %m", filename); + if (r == 0) { + log_debug("No root account found in %s, assuming root is not configured.", filename); + return true; + } + + r = xfopenat(dir_fd, "shadow", "re", O_NOFOLLOW, &shadow); + if (r == -ENOENT) { + log_debug("No shadow file found, assuming root is not configured."); + return true; /* missing */ + } + if (r < 0) + return log_error_errno(r, "Failed to access shadow: %m"); - return arg_force; /* exists, but if --force was given we should still configure the file. */ + struct spwd *j; + while ((r = fgetspent_sane(shadow, &j)) > 0) { + if (!streq(j->sp_namp, "root")) + continue; + + bool unprovisioned = streq_ptr(j->sp_pwdp, PASSWORD_UNPROVISIONED); + log_debug("Root account found, %s.", + unprovisioned ? "with unprovisioned password, treating root as not configured" : + "treating root as configured"); + return unprovisioned; + } + if (r < 0) + return log_error_errno(r, "Failed to read shadow: %m"); + assert(r == 0); + log_debug("No root account found in shadow, assuming root is not configured."); + return true; } static bool locale_is_installed_bool(const char *name) { diff --git a/src/sysusers/sysusers.c b/src/sysusers/sysusers.c index 5aaaf609b2c..12adad516e9 100644 --- a/src/sysusers/sysusers.c +++ b/src/sysusers/sysusers.c @@ -618,7 +618,6 @@ static int write_temporary_shadow(const char *shadow_path, FILE **ret_tmpfile, c struct spwd n = { .sp_namp = i->name, - .sp_pwdp = (char*) PASSWORD_LOCKED_AND_INVALID, .sp_lstchg = lstchg, .sp_min = -1, .sp_max = -1, @@ -641,6 +640,11 @@ static int write_temporary_shadow(const char *shadow_path, FILE **ret_tmpfile, c if (creds_password) n.sp_pwdp = creds_password; + else if (streq(i->name, "root")) + /* Let firstboot set the password later */ + n.sp_pwdp = (char*) PASSWORD_UNPROVISIONED; + else + n.sp_pwdp = (char*) PASSWORD_LOCKED_AND_INVALID; r = putspent_sane(&n, shadow); if (r < 0) diff --git a/units/systemd-firstboot.service b/units/systemd-firstboot.service index 58f3eeb6792..5fee85a2873 100644 --- a/units/systemd-firstboot.service +++ b/units/systemd-firstboot.service @@ -16,7 +16,7 @@ ConditionFirstBoot=yes DefaultDependencies=no After=systemd-remount-fs.service -Before=systemd-sysusers.service systemd-vconsole-setup.service sysinit.target first-boot-complete.target +Before=systemd-vconsole-setup.service sysinit.target first-boot-complete.target Wants=first-boot-complete.target Conflicts=shutdown.target Before=shutdown.target