82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
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#define _POSIX_C_SOURCE 200809L
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#include "password-buffer.h"
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#include "log.h"
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#include "swaylock.h"
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#include <limits.h>
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#include <sys/mman.h>
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static bool mlock_supported = true;
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static long int page_size = 0;
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static long int get_page_size() {
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if (!page_size) {
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page_size = sysconf(_SC_PAGESIZE);
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}
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return page_size;
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}
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// password_buffer_lock expects addr to be page alligned
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static bool password_buffer_lock(char *addr, size_t size) {
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int retries = 5;
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while (mlock(addr, size) != 0 && retries > 0) {
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switch (errno) {
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case EAGAIN:
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retries--;
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if (retries == 0) {
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swaylock_log(LOG_ERROR, "mlock() supported but failed too often.");
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return false;
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}
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break;
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case EPERM:
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swaylock_log_errno(LOG_ERROR, "Unable to mlock() password memory: Unsupported!");
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mlock_supported = false;
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return true;
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default:
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swaylock_log_errno(LOG_ERROR, "Unable to mlock() password memory.");
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return false;
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}
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return false;
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}
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return true;
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}
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// password_buffer_unlock expects addr to be page alligned
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static bool password_buffer_unlock(char *addr, size_t size) {
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if (mlock_supported) {
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if (munlock(addr, size) != 0) {
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swaylock_log_errno(LOG_ERROR, "Unable to munlock() password memory.");
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return false;
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}
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}
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return true;
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}
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char *password_buffer_create(size_t size) {
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void *buffer;
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int result = posix_memalign(&buffer, get_page_size(), size);
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if (result) {
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//posix_memalign doesn't set errno according to the man page
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errno = result;
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swaylock_log_errno(LOG_ERROR, "failed to alloc password buffer");
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return NULL;
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}
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if (!password_buffer_lock(buffer, size)) {
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free(buffer);
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return NULL;
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}
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return buffer;
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}
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void password_buffer_destroy(char *buffer, size_t size) {
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clear_buffer(buffer, size);
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password_buffer_unlock(buffer, size);
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free(buffer);
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}
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