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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 1999-2005, 2010-2015 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pwd.h>
#include <sudoers.h>
#include "sudo_auth.h"
#define DESLEN 13
#define HAS_AGEINFO(p, l) (l == 18 && p[DESLEN] == ',')
int
sudo_passwd_init(const struct sudoers_context *ctx, struct passwd *pw,
sudo_auth *auth)
{
debug_decl(sudo_passwd_init, SUDOERS_DEBUG_AUTH);
/* Only initialize once. */
if (auth->data != NULL)
debug_return_int(AUTH_SUCCESS);
#ifdef HAVE_SKEYACCESS
if (skeyaccess(pw, ctx->user.tty, NULL, NULL) == 0)
debug_return_int(AUTH_FAILURE);
#endif
sudo_setspent();
auth->data = sudo_getepw(pw);
sudo_endspent();
debug_return_int(auth->data ? AUTH_SUCCESS : AUTH_ERROR);
}
#ifdef HAVE_CRYPT
int
sudo_passwd_verify(const struct sudoers_context *ctx, struct passwd *pw,
const char *pass, sudo_auth *auth, struct sudo_conv_callback *callback)
{
char des_pass[9], *epass;
char *pw_epasswd = auth->data;
size_t pw_len;
int ret;
debug_decl(sudo_passwd_verify, SUDOERS_DEBUG_AUTH);
/* An empty plain-text password must match an empty encrypted password. */
if (pass[0] == '\0')
debug_return_int(pw_epasswd[0] ? AUTH_FAILURE : AUTH_SUCCESS);
/*
* Truncate to 8 chars if standard DES since not all crypt()'s do this.
*/
pw_len = strlen(pw_epasswd);
if (pw_len == DESLEN || HAS_AGEINFO(pw_epasswd, pw_len)) {
(void)strlcpy(des_pass, pass, sizeof(des_pass));
pass = des_pass;
}
/*
* Normal UN*X password check.
* HP-UX may add aging info (separated by a ',') at the end so
* only compare the first DESLEN characters in that case.
*/
epass = (char *) crypt(pass, pw_epasswd);
ret = AUTH_FAILURE;
if (epass != NULL) {
if (HAS_AGEINFO(pw_epasswd, pw_len) && strlen(epass) == DESLEN) {
if (strncmp(pw_epasswd, epass, DESLEN) == 0)
ret = AUTH_SUCCESS;
} else {
if (strcmp(pw_epasswd, epass) == 0)
ret = AUTH_SUCCESS;
}
}
explicit_bzero(des_pass, sizeof(des_pass));
debug_return_int(ret);
}
#else
/*
* Constant-time string match, compares "candidate" against "target".
* Will always traverse the entirety of "candidate".
* Returns 0 for match, -1 for mismatch.
*/
static int
timingsafe_strmatch(const char *candidate, const char *target)
{
int ret = 0;
debug_decl(timingsafe_strmatch, SUDOERS_DEBUG_AUTH);
for (;;) {
ret |= *candidate ^ *target;
if (*candidate == '\0')
break;
candidate++;
target += *target != '\0';
}
debug_return_int(ret ? -1 : 0);
}
int
sudo_passwd_verify(const struct sudoers_context *ctx, struct passwd *pw,
const char *pass, sudo_auth *auth, struct sudo_conv_callback *callback)
{
int (* volatile cmp)(const char *, const char *) = timingsafe_strmatch;
const char *pw_passwd = auth->data;
int ret;
debug_decl(sudo_passwd_verify, SUDOERS_DEBUG_AUTH);
/* Simple string compare for systems without crypt(). */
if (cmp(pass, pw_passwd) == 0)
ret = AUTH_SUCCESS;
else
ret = AUTH_FAILURE;
debug_return_int(ret);
}
#endif
int
sudo_passwd_cleanup(const struct sudoers_context *ctx, struct passwd *pw,
sudo_auth *auth, bool force)
{
debug_decl(sudo_passwd_cleanup, SUDOERS_DEBUG_AUTH);
if (auth->data != NULL) {
/* Zero out encrypted password before freeing. */
size_t len = strlen((char *)auth->data);
freezero(auth->data, len);
auth->data = NULL;
}
debug_return_int(AUTH_SUCCESS);
}
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