diff --git a/shadow.c b/shadow.c index be1ac0f..3399d04 100644 --- a/shadow.c +++ b/shadow.c @@ -1,4 +1,5 @@ #define _XOPEN_SOURCE // for crypt +#include #include #include #include @@ -14,15 +15,23 @@ #include "password-buffer.h" #include "swaylock.h" +char *encpw = NULL; + void initialize_pw_backend(int argc, char **argv) { - if (geteuid() != 0) { - swaylock_log(LOG_ERROR, - "swaylock needs to be setuid to read /etc/shadow"); + /* This code runs as root */ + struct passwd *pwent = getpwuid(getuid()); + if (!pwent) { + swaylock_log_errno(LOG_ERROR, "failed to getpwuid"); exit(EXIT_FAILURE); } - - if (!spawn_comm_child()) { - exit(EXIT_FAILURE); + encpw = pwent->pw_passwd; + if (strcmp(encpw, "x") == 0) { + struct spwd *swent = getspnam(pwent->pw_name); + if (!swent) { + swaylock_log_errno(LOG_ERROR, "failed to getspnam"); + exit(EXIT_FAILURE); + } + encpw = swent->sp_pwdp; } if (setgid(getgid()) != 0) { @@ -38,40 +47,21 @@ void initialize_pw_backend(int argc, char **argv) { "able to restore it after setuid/setgid)"); exit(EXIT_FAILURE); } -} - -void run_pw_backend_child(void) { - /* This code runs as root */ - struct passwd *pwent = getpwuid(getuid()); - if (!pwent) { - swaylock_log_errno(LOG_ERROR, "failed to getpwuid"); - exit(EXIT_FAILURE); - } - char *encpw = pwent->pw_passwd; - if (strcmp(encpw, "x") == 0) { - struct spwd *swent = getspnam(pwent->pw_name); - if (!swent) { - swaylock_log_errno(LOG_ERROR, "failed to getspnam"); - exit(EXIT_FAILURE); - } - encpw = swent->sp_pwdp; - } - - /* We don't need any additional logging here because the parent process will - * also fail here and will handle logging for us. */ - if (setgid(getgid()) != 0) { - exit(EXIT_FAILURE); - } - if (setuid(getuid()) != 0) { - exit(EXIT_FAILURE); - } - if (setuid(0) != -1) { - exit(EXIT_FAILURE); - } /* This code does not run as root */ swaylock_log(LOG_DEBUG, "Prepared to authorize user %s", pwent->pw_name); + if (!spawn_comm_child()) { + exit(EXIT_FAILURE); + } + + /* Buffer is only used by the child */ + clear_buffer(encpw, strlen(encpw)); + encpw = NULL; +} + +void run_pw_backend_child(void) { + assert(encpw != NULL); while (1) { char *buf; ssize_t size = read_comm_request(&buf);