diff --git a/man/common-variables.xml b/man/common-variables.xml index 6a6e98d334..991946f60d 100644 --- a/man/common-variables.xml +++ b/man/common-variables.xml @@ -205,9 +205,16 @@ enabled if the effective UID is not the same as the owner of the login session, see geteuid2 and - sd_pid_get_owner_uid3. - In this case, SYSTEMD_PAGERSECURE=1 will be set and pagers which are not known to - implement "secure mode" will not be used at all. + sd_pid_get_owner_uid3, + or when running under + sudo8 or similar + tools ($SUDO_UID is set + It is recommended for other tools to set and check $SUDO_UID as appropriate, + treating it is a common interface.). In those cases, + SYSTEMD_PAGERSECURE=1 will be set and pagers which are not known to implement + "secure mode" will not be used at all. Note that this autodetection only covers the most common + mechanisms to elevate privileges and is intended as convenience. It is recommended to explicitly set + $SYSTEMD_PAGERSECURE or disable the pager. Note that if the $SYSTEMD_PAGER or $PAGER variables are to be honoured, other than to disable the pager, $SYSTEMD_PAGERSECURE must be set diff --git a/src/shared/pager.c b/src/shared/pager.c index 9b8ae76700..f1043ec132 100644 --- a/src/shared/pager.c +++ b/src/shared/pager.c @@ -82,6 +82,22 @@ static int no_quit_on_interrupt(int exe_name_fd, const char *less_opts) { return r; } +static bool running_with_escalated_privileges(void) { + int r; + + if (getenv("SUDO_UID")) + return true; + + uid_t uid; + r = sd_pid_get_owner_uid(0, &uid); + if (r < 0) { + log_debug_errno(r, "sd_pid_get_owner_uid() failed, enabling pager secure mode: %m"); + return true; + } + + return uid != geteuid(); +} + void pager_open(PagerFlags flags) { _cleanup_close_pair_ int fd[2] = EBADF_PAIR, exe_name_pipe[2] = EBADF_PAIR; _cleanup_strv_free_ char **pager_args = NULL; @@ -177,16 +193,9 @@ void pager_open(PagerFlags flags) { * know to be good. */ int use_secure_mode = secure_getenv_bool("SYSTEMD_PAGERSECURE"); bool trust_pager = use_secure_mode >= 0; - if (use_secure_mode == -ENXIO) { - uid_t uid; - - r = sd_pid_get_owner_uid(0, &uid); - if (r < 0) - log_debug_errno(r, "sd_pid_get_owner_uid() failed, enabling pager secure mode: %m"); - - use_secure_mode = r < 0 || uid != geteuid(); - - } else if (use_secure_mode < 0) { + if (use_secure_mode == -ENXIO) + use_secure_mode = running_with_escalated_privileges(); + else if (use_secure_mode < 0) { log_warning_errno(use_secure_mode, "Unable to parse $SYSTEMD_PAGERSECURE, assuming true: %m"); use_secure_mode = true; }