89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
#define _POSIX_C_SOURCE 200809L
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#include <pwd.h>
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#include <security/pam_appl.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "log.h"
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#include "swaylock.h"
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void initialize_pw_backend(void) {
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// TODO: only call pam_start once. keep the same handle the whole time
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}
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static int function_conversation(int num_msg, const struct pam_message **msg,
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struct pam_response **resp, void *data) {
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struct swaylock_password *pw = data;
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/* PAM expects an array of responses, one for each message */
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struct pam_response *pam_reply = calloc(
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num_msg, sizeof(struct pam_response));
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*resp = pam_reply;
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for (int i = 0; i < num_msg; ++i) {
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switch (msg[i]->msg_style) {
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case PAM_PROMPT_ECHO_OFF:
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case PAM_PROMPT_ECHO_ON:
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pam_reply[i].resp = strdup(pw->buffer); // PAM clears and frees this
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break;
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case PAM_ERROR_MSG:
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case PAM_TEXT_INFO:
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break;
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}
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}
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return PAM_SUCCESS;
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}
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static const char *get_pam_auth_error(int pam_status) {
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switch (pam_status) {
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case PAM_AUTH_ERR:
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return "invalid credentials";
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case PAM_CRED_INSUFFICIENT:
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return "swaylock cannot authenticate users; check /etc/pam.d/swaylock "
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"has been installed properly";
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case PAM_AUTHINFO_UNAVAIL:
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return "authentication information unavailable";
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case PAM_MAXTRIES:
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return "maximum number of authentication tries exceeded";
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default:;
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static char msg[64];
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snprintf(msg, sizeof(msg), "unknown error (%d)", pam_status);
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return msg;
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}
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}
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bool attempt_password(struct swaylock_password *pw) {
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struct passwd *passwd = getpwuid(getuid());
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char *username = passwd->pw_name;
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bool success = false;
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const struct pam_conv local_conversation = {
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.conv = function_conversation,
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.appdata_ptr = pw,
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};
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pam_handle_t *local_auth_handle = NULL;
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if (pam_start("swaylock", username, &local_conversation, &local_auth_handle)
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!= PAM_SUCCESS) {
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swaylock_log(LOG_ERROR, "pam_start failed");
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goto out;
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}
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int pam_status = pam_authenticate(local_auth_handle, 0);
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if (pam_status == PAM_SUCCESS) {
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swaylock_log(LOG_DEBUG, "pam_authenticate succeeded");
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success = true;
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} else {
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swaylock_log(LOG_ERROR, "pam_authenticate failed: %s",
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get_pam_auth_error(pam_status));
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}
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if (pam_end(local_auth_handle, pam_status) != PAM_SUCCESS) {
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swaylock_log(LOG_ERROR, "pam_end failed");
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success = false;
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}
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out:
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clear_password_buffer(pw);
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return success;
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}
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