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wolfssh/apps/wolfsshd/auth.c

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/* auth.c
*
* Copyright (C) 2014-2022 wolfSSL Inc.
*
* This file is part of wolfSSH.
*
* wolfSSH is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* wolfSSH is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with wolfSSH. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef WOLFSSH_SSHD
#ifdef __linux__
#define _XOPEN_SOURCE
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#endif
#include <unistd.h>
#include <wolfssh/ssh.h>
#include <wolfssh/internal.h>
#include <wolfssh/log.h>
#include <wolfssl/wolfcrypt/wc_port.h>
#include <wolfssl/wolfcrypt/error-crypt.h>
#include <wolfssl/wolfcrypt/coding.h>
#ifdef NO_INLINE
#include <wolfssh/misc.h>
#else
#define WOLFSSH_MISC_INCLUDED
#include "src/misc.c"
#endif
#include "configuration.h"
#ifndef _WIN32
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#endif
#if !defined(_WIN32) && !(defined(__OSX__) || defined(__APPLE__))
#include <shadow.h>
#define HAVE_SHADOW
#endif
struct WOLFSSHD_AUTH {
CallbackCheckUser checkUserCb;
CallbackCheckPassword checkPasswordCb;
CallbackCheckPublicKey checkPublicKeyCb;
const WOLFSSHD_CONFIG* conf;
int gid;
int uid;
int attempts;
void* heap;
};
#ifndef WOLFSSHD_MAX_PASSWORD_ATTEMPTS
#define WOLFSSHD_MAX_PASSWORD_ATTEMPTS 3
#endif
#ifndef MAX_LINE_SZ
#define MAX_LINE_SZ 900
#endif
#ifndef MAX_PATH_SZ
#define MAX_PATH_SZ 80
#endif
#if 0
/* this could potentially be useful in a deeply embeded future port */
/* Map user names to passwords */
/* Use arrays for username and p. The password or public key can
* be hashed and the hash stored here. Then I won't need the type. */
struct USER_NODE {
byte type;
byte username[32];
word32 usernameSz;
byte fingerprint[WC_SHA256_DIGEST_SIZE];
struct USER_NODE* next;
};
/* Takes a users input and adds it to the list of accepted users
* 'value' can be a users password / public key / or certificate
* returns an updated list on success (i.e. 'new' -> 'list' -> ...) or NULL
* on failure
*/
USER_NODE* AddNewUser(USER_NODE* list, byte type, const byte* username,
word32 usernameSz, const byte* value, word32 valueSz)
{
USER_NODE* map;
map = (USER_NODE*)WMALLOC(sizeof(USER_NODE), NULL, 0);
if (map != NULL) {
map->type = type;
if (usernameSz >= sizeof(map->username))
usernameSz = sizeof(map->username) - 1;
WMEMCPY(map->username, username, usernameSz + 1);
map->username[usernameSz] = 0;
map->usernameSz = usernameSz;
if (type != WOLFSSH_USERAUTH_NONE) {
wc_Sha256Hash(value, valueSz, map->fingerprint);
}
map->next = list;
}
return map;
}
#endif
enum {
WSSHD_AUTH_FAILURE = 0,
WSSHD_AUTH_SUCCESS = 1
};
/* TODO: Can use wolfSSH_ReadKey_buffer? */
static int CheckAuthKeysLine(char* line, word32 lineSz, const byte* key,
word32 keySz)
{
int ret = WSSHD_AUTH_SUCCESS;
char* type;
char* keyCandBase64; /* cand == candidate */
word32 keyCandBase64Sz;
byte* keyCand = NULL;
word32 keyCandSz;
char* last;
enum {
#ifdef WOLFSSH_CERTS
NUM_ALLOWED_TYPES = 9
#else
NUM_ALLOWED_TYPES = 5
#endif
};
static const char* allowedTypes[NUM_ALLOWED_TYPES] = {
"ssh-rsa",
"ssh-ed25519",
"ecdsa-sha2-nistp256",
"ecdsa-sha2-nistp384",
"ecdsa-sha2-nistp521",
#ifdef WOLFSSH_CERTS
"x509v3-ssh-rsa",
"x509v3-ecdsa-sha2-nistp256",
"x509v3-ecdsa-sha2-nistp384",
"x509v3-ecdsa-sha2-nistp521",
#endif
};
int typeOk = 0;
int i;
if (line == NULL || lineSz == 0 || key == NULL || keySz == 0) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WSSHD_AUTH_SUCCESS) {
if ((type = WSTRTOK(line, " ", &last)) == NULL) {
ret = WS_FATAL_ERROR;
}
else if ((keyCandBase64 = WSTRTOK(NULL, " ", &last)) == NULL) {
ret = WS_FATAL_ERROR;
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
for (i = 0; i < NUM_ALLOWED_TYPES; ++i) {
if (WSTRCMP(type, allowedTypes[i]) == 0) {
typeOk = 1;
break;
}
}
if (!typeOk) {
ret = WS_FATAL_ERROR;
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
keyCandBase64Sz = (word32)XSTRLEN(keyCandBase64);
keyCandSz = (keyCandBase64Sz * 3 + 3) / 4;
keyCand = (byte*)WMALLOC(keyCandSz, NULL, DYNTYPE_BUFFER);
if (keyCand == NULL) {
ret = WS_MEMORY_E;
}
else {
if (Base64_Decode((byte*)keyCandBase64, keyCandBase64Sz, keyCand,
&keyCandSz) != 0) {
ret = WS_FATAL_ERROR;
}
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
if (keyCandSz != keySz || WMEMCMP(key, keyCand, keySz) != 0) {
ret = WSSHD_AUTH_FAILURE;
}
}
if (keyCand != NULL) {
WFREE(keyCand, NULL, DYNTYPE_BUFFER);
}
return ret;
}
#ifndef _WIN32
#ifdef WOLFSSH_USE_PAM
static int CheckPasswordPAM(const char* usr, const byte* pw, word32 pwSz)
{
(void)usr;
(void)pw;
(void)pwSz;
return 0;
}
#else
#if 0
static int ExtractSalt(char* hash, char** salt, int saltSz)
{
int ret = WS_SUCCESS;
int idx = 0;
char* p;
if (hash == NULL || salt == NULL || *salt == NULL || saltSz <= 0) {
ret = WS_SUCCESS;
}
if (ret == 0) {
if (hash[idx] != '$') {
ret = WS_FATAL_ERROR;
}
else {
++idx;
if (idx >= saltSz) {
ret = WS_BUFFER_E;
}
}
}
if (ret == 0) {
p = strstr(hash + idx, "$");
if (p == NULL) {
ret = -1;
}
else {
idx += (p - hash);
if (idx >= saltSz) {
ret = WS_BUFFER_E;
}
}
}
if (ret == 0) {
p = strstr(p + 1, "$");
if (p == NULL) {
ret = WS_FATAL_ERROR;
}
else {
idx += (p - (hash + idx) + 1);
if (idx >= saltSz) {
ret = WS_BUFFER_E;
}
}
}
if (ret == 0) {
memcpy(*salt, hash, idx);
(*salt)[idx] = 0;
}
return ret;
}
#endif
#if defined(WOLFSSH_HAVE_LIBCRYPT) || defined(WOLFSSH_HAVE_LIBLOGIN)
static int CheckPasswordHashUnix(const char* input, char* stored)
{
int ret = WSSHD_AUTH_SUCCESS;
char* hashedInput;
if (input == NULL || stored == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WSSHD_AUTH_SUCCESS) {
hashedInput = crypt(input, stored);
if (hashedInput == NULL) {
ret = WS_FATAL_ERROR;
}
else {
if (WMEMCMP(hashedInput, stored, WSTRLEN(stored)) != 0) {
ret = WSSHD_AUTH_FAILURE;
}
}
}
return ret;
}
#endif /* WOLFSSH_HAVE_LIBCRYPT || WOLFSSH_HAVE_LIBLOGIN */
static int CheckPasswordUnix(const char* usr, const byte* pw, word32 pwSz)
{
int ret = WS_SUCCESS;
char* pwStr = NULL;
struct passwd* pwInfo;
#ifdef HAVE_SHADOW
struct spwd* shadowInfo;
#endif
/* The hash of the user's password stored on the system. */
char* storedHash;
char* storedHashCpy = NULL;
if (usr == NULL || pw == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
pwStr = (char*)WMALLOC(pwSz + 1, NULL, DYNTYPE_STRING);
if (pwStr == NULL) {
ret = WS_MEMORY_E;
}
else {
XMEMCPY(pwStr, pw, pwSz);
pwStr[pwSz] = 0;
}
}
if (ret == WS_SUCCESS) {
pwInfo = getpwnam((const char*)usr);
if (pwInfo == NULL) {
/* user name not found on system */
ret = WS_FATAL_ERROR;
}
}
if (ret == WS_SUCCESS) {
#ifdef HAVE_SHADOW
if (pwInfo->pw_passwd[0] == 'x') {
#ifdef WOLFSSH_HAVE_LIBCRYPT
shadowInfo = getspnam((const char*)usr);
#else
shadowInfo = getspnam((char*)usr);
#endif
if (shadowInfo == NULL) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Error getting user password info");
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Possibly permisions level error?"
" i.e SSHD not ran as sudo");
ret = WS_FATAL_ERROR;
}
else {
storedHash = shadowInfo->sp_pwdp;
}
}
else
#endif
{
storedHash = pwInfo->pw_passwd;
}
}
if (ret == WS_SUCCESS) {
storedHashCpy = WSTRDUP(storedHash, NULL, DYNTYPE_STRING);
if (storedHash == NULL) {
ret = WS_MEMORY_E;
}
}
if (ret == WS_SUCCESS) {
#if defined(WOLFSSH_HAVE_LIBCRYPT) || defined(WOLFSSH_HAVE_LIBLOGIN)
ret = CheckPasswordHashUnix(pwStr, storedHashCpy);
#else
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] No compiled in password check");
ret = WS_NOT_COMPILED;
#endif
}
if (pwStr != NULL) {
WFREE(pwStr, NULL, DYNTYPE_STRING);
}
if (storedHashCpy != NULL) {
WFREE(storedHashCpy, NULL, DYNTYPE_STRING);
}
return ret;
}
#endif /* WOLFSSH_USE_PAM */
#endif /* !_WIN32 */
#ifndef _WIN32
static int CheckUserUnix(const char* name) {
int ret = WSSHD_AUTH_FAILURE;
struct passwd* pwInfo;
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Unix check user");
errno = 0;
pwInfo = getpwnam(name);
if (pwInfo == NULL) {
if (errno != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error calling getpwnam for user "
"%s.", name);
ret = WS_FATAL_ERROR;
}
}
else {
ret = WSSHD_AUTH_SUCCESS;
}
return ret;
}
static const char authKeysDefault[] = ".ssh/authorized_keys";
static char authKeysPattern[MAX_PATH_SZ] = {0};
void SetAuthKeysPattern(const char* pattern)
{
if (pattern != NULL) {
WMEMSET(authKeysPattern, 0, sizeof(authKeysPattern));
WSTRNCPY(authKeysPattern, pattern, sizeof(authKeysPattern) - 1);
}
}
static int ResolveAuthKeysPath(const char* homeDir, char* resolved)
{
int ret = WS_SUCCESS;
char* idx;
int homeDirSz;
const char* suffix = authKeysDefault;
if (homeDir == NULL || resolved == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (*authKeysPattern != 0) {
/* TODO: token substitutions (e.g. %h) */
if (*authKeysPattern == '/') {
WSTRNCPY(resolved, authKeysPattern, MAX_PATH_SZ);
return WS_SUCCESS;
}
else {
suffix = authKeysPattern;
}
}
}
if (ret == WS_SUCCESS) {
idx = resolved;
homeDirSz = (int)XSTRLEN(homeDir);
if (homeDirSz + 1 + WSTRLEN(suffix) >= MAX_PATH_SZ) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Path for key file larger than max allowed");
ret = WS_FATAL_ERROR;
}
if (ret == WS_SUCCESS) {
XMEMCPY(idx, homeDir, homeDirSz);
idx += homeDirSz;
*(idx++) = '/';
/* Intentionally copying the null term from suffix. */
XMEMCPY(idx, suffix, WSTRLEN(suffix));
}
}
return ret;
}
static int CheckPublicKeyUnix(const char* name,
const WS_UserAuthData_PublicKey* pubKeyCtx,
const char* usrCaKeysFile)
{
int ret = WSSHD_AUTH_SUCCESS;
int rc;
struct passwd* pwInfo;
char* authKeysFile = NULL;
XFILE f = XBADFILE;
char* lineBuf = NULL;
char* current;
word32 currentSz;
int foundKey = 0;
char authKeysPath[MAX_PATH_SZ];
#ifdef WOLFSSH_OSSH_CERTS
if (pubKeyCtx->isOsshCert) {
byte* caKey = NULL;
word32 caKeySz;
const byte* caKeyType = NULL;
word32 caKeyTypeSz;
byte fingerprint[WC_SHA256_DIGEST_SIZE];
if (pubKeyCtx->caKey == NULL ||
pubKeyCtx->caKeySz != WC_SHA256_DIGEST_SIZE) {
ret = WS_FATAL_ERROR;
}
if (ret == WSSHD_AUTH_SUCCESS) {
f = XFOPEN(usrCaKeysFile, "rb");
if (f == XBADFILE) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Unable to open %s",
usrCaKeysFile);
ret = WS_BAD_FILE_E;
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
lineBuf = (char*)WMALLOC(MAX_LINE_SZ, NULL, DYNTYPE_BUFFER);
if (lineBuf == NULL) {
ret = WS_MEMORY_E;
}
}
while (ret == WSSHD_AUTH_SUCCESS &&
(current = XFGETS(lineBuf, MAX_LINE_SZ, f)) != NULL) {
currentSz = (word32)XSTRLEN(current);
/* remove leading spaces */
while (currentSz > 0 && current[0] == ' ') {
currentSz = currentSz - 1;
current = current + 1;
}
if (currentSz <= 1) {
continue; /* empty line */
}
if (current[0] == '#') {
continue; /* commented out line */
}
rc = wolfSSH_ReadKey_buffer((const byte*)current, currentSz,
WOLFSSH_FORMAT_SSH, &caKey, &caKeySz,
&caKeyType, &caKeyTypeSz, NULL);
if (rc == WS_SUCCESS) {
rc = wc_Hash(WC_HASH_TYPE_SHA256, caKey, caKeySz, fingerprint,
WC_SHA256_DIGEST_SIZE);
if (rc == 0 && WMEMCMP(fingerprint, pubKeyCtx->caKey,
WC_SHA256_DIGEST_SIZE) == 0) {
foundKey = 1;
break;
}
}
}
}
else
#endif /* WOLFSSH_OSSH_CERTS */
{
errno = 0;
pwInfo = getpwnam((const char*)name);
if (pwInfo == NULL) {
if (errno != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error calling getpwnam for user "
"%s.", name);
}
ret = WS_FATAL_ERROR;
}
if (ret == WSSHD_AUTH_SUCCESS) {
WMEMSET(authKeysPath, 0, sizeof(authKeysPath));
rc = ResolveAuthKeysPath(pwInfo->pw_dir, authKeysPath);
if (rc != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Failed to resolve authorized keys"
" file path.");
ret = rc;
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
f = XFOPEN(authKeysPath, "rb");
if (f == XBADFILE) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Unable to open %s",
authKeysPath);
ret = WS_BAD_FILE_E;
}
}
if (ret == WSSHD_AUTH_SUCCESS) {
lineBuf = (char*)WMALLOC(MAX_LINE_SZ, NULL, DYNTYPE_BUFFER);
if (lineBuf == NULL) {
ret = WS_MEMORY_E;
}
}
while (ret == WSSHD_AUTH_SUCCESS &&
(current = XFGETS(lineBuf, MAX_LINE_SZ, f)) != NULL) {
currentSz = (word32)XSTRLEN(current);
/* remove leading spaces */
while (currentSz > 0 && current[0] == ' ') {
currentSz = currentSz - 1;
current = current + 1;
}
if (currentSz <= 1) {
continue; /* empty line */
}
if (current[0] == '#') {
continue; /* commented out line */
}
rc = CheckAuthKeysLine(current, currentSz, pubKeyCtx->publicKey,
pubKeyCtx->publicKeySz);
if (rc == WSSHD_AUTH_SUCCESS) {
foundKey = 1;
break;
}
else if (rc < 0) {
ret = rc;
break;
}
}
}
if (f != XBADFILE) {
XFCLOSE(f);
}
if (ret == WSSHD_AUTH_SUCCESS && !foundKey) {
ret = WSSHD_AUTH_FAILURE;
}
if (lineBuf != NULL) {
WFREE(lineBuf, NULL, DYNTYPE_BUFFER);
}
if (authKeysFile != NULL) {
WFREE(authKeysFile, NULL, DYNTYPE_STRING);
}
(void)usrCaKeysFile;
return ret;
}
#endif /* !_WIN32*/
/* return WOLFSSH_USERAUTH_SUCCESS on success */
static int DoCheckUser(const char* usr, WOLFSSHD_AUTH* auth)
{
int ret = WOLFSSH_USERAUTH_SUCCESS;
int rc;
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Checking user name %s", usr);
if (wolfSSHD_ConfigGetPermitRoot(auth->conf) == 0) {
if (XSTRCMP(usr, "root") == 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Login as root not permited");
ret = WOLFSSH_USERAUTH_REJECTED;
}
}
if (ret == WOLFSSH_USERAUTH_SUCCESS) {
rc = auth->checkUserCb(usr);
if (rc == WSSHD_AUTH_SUCCESS) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] User ok.");
ret = WOLFSSH_USERAUTH_SUCCESS;
}
else if (ret == WSSHD_AUTH_FAILURE) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] User %s doesn't exist.", usr);
ret = WOLFSSH_USERAUTH_INVALID_USER;
}
else {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error looking up user %s.", usr);
ret = WOLFSSH_USERAUTH_FAILURE;
}
}
return ret;
}
/* @TODO this will take in a pipe or equivalent to talk to a privileged thread
* rathar than having WOLFSSHD_AUTH directly with privilege separation */
static int RequestAuthentication(WS_UserAuthData* authData,
WOLFSSHD_AUTH* authCtx)
{
int ret;
int rc;
const char* usr;
if (authData == NULL || authCtx == NULL) {
return WOLFSSH_USERAUTH_FAILURE;
}
usr = (const char*)authData->username;
ret = DoCheckUser(usr, authCtx);
/* temporarily elevate permissions */
if (ret == WOLFSSH_USERAUTH_SUCCESS &&
wolfSSHD_AuthRaisePermissions(authCtx) != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Failure to raise permissions for auth");
ret = WOLFSSH_USERAUTH_FAILURE;
}
if (ret == WOLFSSH_USERAUTH_SUCCESS &&
authData->type == WOLFSSH_USERAUTH_PASSWORD) {
if (wolfSSHD_ConfigGetPwAuth(authCtx->conf) != 1) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Password authentication not "
"allowed by configuration!");
ret = WOLFSSH_USERAUTH_REJECTED;
}
/* Check if password is valid for this user. */
/* first handle empty password cases */
else if (authData->sf.password.passwordSz == 0 &&
wolfSSHD_ConfigGetPermitEmptyPw(authCtx->conf) != 1) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Empty passwords not allowed by "
"configuration!");
ret = WOLFSSH_USERAUTH_FAILURE;
}
else {
rc = authCtx->checkPasswordCb(usr, authData->sf.password.password,
authData->sf.password.passwordSz);
if (rc == WSSHD_AUTH_SUCCESS) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Password ok.");
}
else if (rc == WSSHD_AUTH_FAILURE) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Password incorrect.");
ret = WOLFSSH_USERAUTH_INVALID_PASSWORD;
authCtx->attempts--;
if (authCtx->attempts == 0) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Too many bad password attempts!");
ret = WOLFSSH_USERAUTH_REJECTED;
}
}
else {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error checking password.");
ret = WOLFSSH_USERAUTH_FAILURE;
}
}
}
if (ret == WOLFSSH_USERAUTH_SUCCESS &&
authData->type == WOLFSSH_USERAUTH_PUBLICKEY) {
/* if this is a certificate and no specific authorized keys file has
* been set then rely on CA to have verified the cert */
if (authData->sf.publicKey.isCert &&
!wolfSSHD_ConfigGetAuthKeysFileSet(authCtx->conf)) {
wolfSSH_Log(WS_LOG_INFO,
"[SSHD] Relying on CA for public key check");
ret = WOLFSSH_USERAUTH_SUCCESS;
}
else {
/* if not a certificate then parse through authorized key file */
rc = authCtx->checkPublicKeyCb(usr, &authData->sf.publicKey,
wolfSSHD_ConfigGetUserCAKeysFile(authCtx->conf));
if (rc == WSSHD_AUTH_SUCCESS) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Public key ok.");
ret = WOLFSSH_USERAUTH_SUCCESS;
}
else if (rc == WSSHD_AUTH_FAILURE) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Public key not authorized.");
ret = WOLFSSH_USERAUTH_INVALID_PUBLICKEY;
}
else {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error checking public key.");
ret = WOLFSSH_USERAUTH_FAILURE;
}
}
}
if (wolfSSHD_AuthReducePermissions(authCtx) != WS_SUCCESS) {
/* stop everything if not able to reduce permissions level */
exit(1);
}
return ret;
}
/* return WOLFSSH_USERAUTH_SUCCESS on success */
int DefaultUserAuth(byte authType, WS_UserAuthData* authData, void* ctx)
{
int ret = WOLFSSH_USERAUTH_SUCCESS;
WOLFSSHD_AUTH* authCtx;
if (ctx == NULL) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] No auth callbacks passed in");
return WOLFSSH_USERAUTH_FAILURE;
}
else {
authCtx = (WOLFSSHD_AUTH*)ctx;
if (authCtx->checkUserCb == NULL) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] No way to check the user is set");
return WOLFSSH_USERAUTH_FAILURE;
}
}
if (authData == NULL) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] No authData passed in");
return WOLFSSH_USERAUTH_FAILURE;
}
if (authType != WOLFSSH_USERAUTH_PASSWORD &&
#ifdef WOLFSSH_ALLOW_USERAUTH_NONE
authType != WOLFSSH_USERAUTH_NONE &&
#endif
authType != WOLFSSH_USERAUTH_PUBLICKEY) {
ret = WOLFSSH_USERAUTH_INVALID_AUTHTYPE;
}
/* call to possibly privileged authenticator for password check */
if (ret == WOLFSSH_USERAUTH_SUCCESS) {
ret = RequestAuthentication(authData, authCtx);
}
return ret;
}
int DefaultUserAuthTypes(WOLFSSH* ssh, void* ctx)
{
WOLFSSHD_CONFIG* usrConf;
WOLFSSHD_AUTH* authCtx;
char* usr;
int ret = 0;
if (ssh == NULL || ctx == NULL)
return WS_BAD_ARGUMENT;
authCtx = (WOLFSSHD_AUTH*)ctx;
/* get configuration for user */
usr = wolfSSH_GetUsername(ssh);
usrConf = wolfSSHD_AuthGetUserConf(authCtx, usr, NULL, NULL,
NULL, NULL, NULL);
if (usrConf == NULL) {
ret = WS_BAD_ARGUMENT;
}
else {
if (wolfSSHD_ConfigGetPwAuth(usrConf) == 1) {
ret |= WOLFSSH_USERAUTH_PASSWORD;
}
ret |= WOLFSSH_USERAUTH_PUBLICKEY;
}
return ret;
}
static int SetDefaultUserCheck(WOLFSSHD_AUTH* auth)
{
int ret = WS_NOT_COMPILED;
#ifdef _WIN32
/* TODO: Implement for Windows. */
#else
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Setting default Unix user name check");
auth->checkUserCb = CheckUserUnix;
ret = WS_SUCCESS;
#endif
return ret;
}
static int SetDefaultPasswordCheck(WOLFSSHD_AUTH* auth)
{
int ret = WS_NOT_COMPILED;
#ifdef _WIN32
/* TODO: Add CheckPasswordWin. */
#elif defined(WOLFSSH_USE_PAM)
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Setting PAM password check");
auth->checkPasswordCb = CheckPasswordPAM;
ret = WS_SUCCESS;
#else
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Setting Unix password check");
auth->checkPasswordCb = CheckPasswordUnix;
ret = WS_SUCCESS;
#endif
return ret;
}
static int SetDefaultPublicKeyCheck(WOLFSSHD_AUTH* auth)
{
int ret = WS_NOT_COMPILED;
#ifdef _WIN32
/* TODO: Implement for Windows. */
#else
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Setting Unix public key check");
auth->checkPublicKeyCb = CheckPublicKeyUnix;
ret = WS_SUCCESS;
#endif
return ret;
}
/* Sets the default functions to be used for authentication of peer.
* Later the default functions could be overriden if needed.
* returns a newly created WOLFSSHD_AUTH struct success */
WOLFSSHD_AUTH* wolfSSHD_AuthCreateUser(void* heap, const WOLFSSHD_CONFIG* conf)
{
WOLFSSHD_AUTH* auth;
auth = (WOLFSSHD_AUTH*)WMALLOC(sizeof(WOLFSSHD_AUTH), heap, DYNTYPE_SSHD);
if (auth != NULL) {
int ret;
struct passwd* pwInfo;
const char* usr = "sshd";
auth->heap = heap;
auth->conf = conf;
auth->attempts = WOLFSSHD_MAX_PASSWORD_ATTEMPTS;
/* set the default user checking based on build */
ret = SetDefaultUserCheck(auth);
if (ret != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting default user check.");
}
/* set the default password checking based on build */
if (ret == WS_SUCCESS) {
ret = SetDefaultPasswordCheck(auth);
if (ret != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting default "
"password check.");
}
}
/* set the default public key checking based on build */
if (ret == WS_SUCCESS) {
ret = SetDefaultPublicKeyCheck(auth);
if (ret != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting default "
"public key check.");
}
}
if (ret == WS_SUCCESS) {
pwInfo = getpwnam(usr);
if (pwInfo == NULL) {
/* user name not found on system */
wolfSSH_Log(WS_LOG_INFO, "[SSHD] No sshd user found to use");
ret = WS_FATAL_ERROR;
}
}
if (ret == WS_SUCCESS) {
auth->gid = pwInfo->pw_gid;
auth->uid = pwInfo->pw_uid;
}
/* error case in setting one of the default callbacks */
if (ret != WS_SUCCESS) {
(void)wolfSSHD_AuthFreeUser(auth);
auth = NULL;
}
}
return auth;
}
/* returns WS_SUCCESS on success */
int wolfSSHD_AuthFreeUser(WOLFSSHD_AUTH* auth)
{
if (auth != NULL) {
WFREE(auth, auth->heap, DYNTYPE_SSHD);
}
return WS_SUCCESS;
}
/* return WS_SUCCESS on success */
int wolfSSHD_AuthRaisePermissions(WOLFSSHD_AUTH* auth)
{
int ret = 0;
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Attempting to raise permissions level");
if (auth) {
if (setegid(0) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error rasing gid");
ret = WS_FATAL_ERROR;
}
if (seteuid(0) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error rasing uid");
ret = WS_FATAL_ERROR;
}
}
else {
ret = WS_BAD_ARGUMENT;
}
return ret;
}
/* return WS_SUCCESS on success */
int wolfSSHD_AuthReducePermissionsUser(WOLFSSHD_AUTH* auth, WUID_T uid,
WGID_T gid)
{
if (setregid(gid, gid) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting user gid");
return WS_FATAL_ERROR;
}
if (setreuid(uid, uid) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting user uid");
return WS_FATAL_ERROR;
}
(void)auth;
return WS_SUCCESS;
}
/* return WS_SUCCESS on success */
int wolfSSHD_AuthReducePermissions(WOLFSSHD_AUTH* auth)
{
byte flag = 0;
int ret = WS_SUCCESS;
flag = wolfSSHD_ConfigGetPrivilegeSeparation(auth->conf);
if (flag == WOLFSSHD_PRIV_SEPARAT || flag == WOLFSSHD_PRIV_SANDBOX) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Lowering permissions level");
if (auth) {
if (setegid(auth->gid) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting sshd gid");
ret = WS_FATAL_ERROR;
}
if (seteuid(auth->uid) != 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error setting sshd uid");
ret = WS_FATAL_ERROR;
}
}
else {
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
/* return the time in seconds for grace timeout period */
long wolfSSHD_AuthGetGraceTime(const WOLFSSHD_AUTH* auth)
{
long ret = WS_BAD_ARGUMENT;
if (auth != NULL && auth->conf != NULL) {
ret = wolfSSHD_ConfigGetGraceTime(auth->conf);
}
return ret;
}
/* return the user configuration */
WOLFSSHD_CONFIG* wolfSSHD_AuthGetUserConf(const WOLFSSHD_AUTH* auth,
const char* usr, const char* host,
const char* localAdr, word16* localPort, const char* RDomain,
const char* adr)
{
struct group* g = NULL;
WOLFSSHD_CONFIG* ret = NULL;
if (auth != NULL) {
struct passwd *p_passwd;
char* gName = NULL;
if (usr != NULL) {
p_passwd = getpwnam((const char *)usr);
if (p_passwd == NULL) {
return NULL;
}
g = getgrgid(p_passwd->pw_gid);
if (g == NULL) {
return NULL;
}
gName = g->gr_name;
}
ret = wolfSSHD_GetUserConf(auth->conf, usr, gName, host, localAdr,
localPort, RDomain, adr);
}
return ret;
}
#endif /* WOLFSSH_SSHD */
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