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wolfssh/apps/wolfsshd/configuration.c

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/* configuration.c
*
* Copyright (C) 2014-2026 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 WOLFSSL_USER_SETTINGS
#include <wolfssl/wolfcrypt/settings.h>
#else
#include <wolfssl/options.h>
#endif
#ifdef WOLFSSH_SSHD
/* functions for parsing out options from a config file and for handling loading
* key/certs using the env. filesystem */
/* WOLFSSHD_STATIC is defined in configuration.h so configuration.c and auth.c
* share the same test-visibility convention. */
#include <wolfssh/ssh.h>
#include <wolfssh/internal.h>
#include <wolfssh/log.h>
#include <wolfssh/port.h>
#include <wolfssl/wolfcrypt/wc_port.h>
#include <wolfssl/wolfcrypt/error-crypt.h>
#ifdef NO_INLINE
#include <wolfssh/misc.h>
#else
#define WOLFSSH_MISC_INCLUDED
#include "src/misc.c"
#endif
#include "configuration.h"
#ifndef WIN32
#include <dirent.h>
#endif
#ifdef WIN32
#include <process.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
struct WOLFSSHD_CONFIG {
void* heap;
char* usrAppliesTo; /* NULL means all users */
char* groupAppliesTo; /* NULL means all groups */
char* banner;
char* chrootDir;
char* ciphers;
char* hostKeyFile;
char* hostCertFile;
char* userCAKeysFile;
char* hostKeyAlgos;
char* kekAlgos;
char* listenAddress;
char* authKeysFile;
char* forceCmd;
char* pidFile;
WOLFSSHD_CONFIG* next; /* next config in list */
long loginTimer;
word16 port;
byte usePrivilegeSeparation:2;
byte passwordAuth:1;
byte pubKeyAuth:1;
byte permitRootLogin:1;
byte permitEmptyPasswords:1;
byte authKeysFileSet:1; /* if not set then no explicit authorized keys */
};
/* Maximum depth of nested Include directives. Bounds the recursion
* through wolfSSHD_ConfigLoad -> ParseConfigLine -> HandleConfigOption
* -> HandleInclude -> wolfSSHD_ConfigLoad. */
#ifndef WOLFSSHD_MAX_INCLUDE_DEPTH
#define WOLFSSHD_MAX_INCLUDE_DEPTH 16
#endif
static int ConfigLoad(WOLFSSHD_CONFIG* conf, const char* filename, int depth);
static int CountWhitespace(const char* in, int inSz, byte inv);
static int SetFileString(char** dst, const char* src, void* heap);
/* convert a string into seconds, handles if 'm' for minutes follows the string
* number, i.e. 2m
* Returns the value on success and negative value on failure */
static long GetConfigInt(const char* in, int inSz, int isTime, void* heap)
{
long ret = 0;
int mult = 1; /* multiplier */
int sz = inSz;
if (in == NULL || inSz <= 0) {
ret = WS_BAD_ARGUMENT;
}
/* check for multipliers */
if (ret == 0 && isTime) {
if (in[sz - 1] == 'm') {
sz--;
mult = 60;
}
else if (in[sz - 1] == 'h') {
sz--;
mult = 60*60;
}
}
if (ret == 0) {
char* num = (char*)WMALLOC(sz + 1, heap, DYNTYPE_SSHD);
if (num == NULL) {
ret = WS_MEMORY_E;
}
else {
WMEMCPY(num, in, sz);
num[sz] = '\0';
ret = atol(num);
if (ret == 0 && WSTRCMP(in, "0") != 0) {
ret = WS_BAD_ARGUMENT;
}
else if (ret > 0) {
ret = ret * mult;
}
WFREE(num, heap, DYNTYPE_SSHD);
}
}
return ret;
}
/* returns WS_SUCCESS on success, removes trailng newlines */
static int CreateString(char** out, const char* in, int inSz, void* heap)
{
int ret = WS_SUCCESS;
int idx = 0, tail, sz = 0;
if (in == NULL && inSz != 0) {
return WS_BAD_ARGUMENT;
}
if (in == NULL) {
/* "created" an empty string */
return ret;
}
/* remove leading white spaces */
while (idx < inSz && in[idx] == ' ') idx++;
if (idx == inSz) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
for (tail = inSz - 1; tail > idx; tail--) {
if (in[tail] != '\n' && in[tail] != ' ' && in[tail] != '\r') {
break;
}
}
sz = tail - idx + 1; /* +1 to account for index of 0 */
if (sz > inSz - idx) {
ret = WS_BAD_ARGUMENT;
}
}
/* malloc new string and set it */
if (ret == WS_SUCCESS) {
*out = (char*)WMALLOC(sz + 1, heap, DYNTYPE_SSHD);
if (*out == NULL) {
ret = WS_MEMORY_E;
}
else {
XMEMCPY(*out, in + idx, sz);
*(*out + sz) = '\0';
}
}
return ret;
}
static void FreeString(char** in, void* heap)
{
if (*in != NULL) {
WFREE(*in, heap, DYNTYPE_SSHD);
*in = NULL;
}
(void)heap;
}
/* returns a new WOLFSSHD_CONFIG on success and NULL on failure */
WOLFSSHD_CONFIG* wolfSSHD_ConfigNew(void* heap)
{
WOLFSSHD_CONFIG* ret;
ret = (WOLFSSHD_CONFIG*)WMALLOC(sizeof(WOLFSSHD_CONFIG), heap,
DYNTYPE_SSHD);
if (ret == NULL) {
fprintf(stderr, "Issue malloc'ing config structure for sshd\n");
}
else {
WMEMSET(ret, 0, sizeof(WOLFSSHD_CONFIG));
/* default values */
ret->port = 22;
ret->passwordAuth = 1;
ret->pubKeyAuth = 1;
ret->loginTimer = 120;
}
return ret;
}
/* on success return a newly create WOLFSSHD_CONFIG structure that has the
* same values set as the input 'conf'. User and group match values are not
* copied */
static WOLFSSHD_CONFIG* wolfSSHD_ConfigCopy(WOLFSSHD_CONFIG* conf)
{
int ret = WS_SUCCESS;
WOLFSSHD_CONFIG* newConf;
newConf = wolfSSHD_ConfigNew(conf->heap);
if (newConf != NULL) {
if (conf->banner) {
ret = CreateString(&newConf->banner, conf->banner,
(int)WSTRLEN(conf->banner),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->chrootDir) {
ret = CreateString(&newConf->chrootDir, conf->chrootDir,
(int)WSTRLEN(conf->chrootDir),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->ciphers) {
ret = CreateString(&newConf->ciphers, conf->ciphers,
(int)WSTRLEN(conf->ciphers),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->hostKeyFile) {
ret = CreateString(&newConf->hostKeyFile, conf->hostKeyFile,
(int)WSTRLEN(conf->hostKeyFile),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->hostKeyAlgos) {
ret = CreateString(&newConf->hostKeyAlgos, conf->hostKeyAlgos,
(int)WSTRLEN(conf->hostKeyAlgos),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->kekAlgos) {
ret = CreateString(&newConf->kekAlgos, conf->kekAlgos,
(int)WSTRLEN(conf->kekAlgos),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->listenAddress) {
ret = CreateString(&newConf->listenAddress, conf->listenAddress,
(int)WSTRLEN(conf->listenAddress),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->authKeysFile) {
ret = CreateString(&newConf->authKeysFile, conf->authKeysFile,
(int)WSTRLEN(conf->authKeysFile),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->hostCertFile) {
ret = CreateString(&newConf->hostCertFile, conf->hostCertFile,
(int)WSTRLEN(conf->hostCertFile),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->pidFile) {
ret = CreateString(&newConf->pidFile, conf->pidFile,
(int)WSTRLEN(conf->pidFile),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->userCAKeysFile) {
ret = CreateString(&newConf->userCAKeysFile, conf->userCAKeysFile,
(int)WSTRLEN(conf->userCAKeysFile),
newConf->heap);
}
if (ret == WS_SUCCESS && conf->forceCmd) {
ret = CreateString(&newConf->forceCmd, conf->forceCmd,
(int)WSTRLEN(conf->forceCmd),
newConf->heap);
}
if (ret == WS_SUCCESS) {
newConf->loginTimer = conf->loginTimer;
newConf->port = conf->port;
newConf->passwordAuth = conf->passwordAuth;
newConf->pubKeyAuth = conf->pubKeyAuth;
newConf->usePrivilegeSeparation = conf->usePrivilegeSeparation;
newConf->permitRootLogin = conf->permitRootLogin;
newConf->permitEmptyPasswords = conf->permitEmptyPasswords;
newConf->authKeysFileSet = conf->authKeysFileSet;
}
else {
wolfSSHD_ConfigFree(newConf);
newConf = NULL;
}
}
return newConf;
}
void wolfSSHD_ConfigFree(WOLFSSHD_CONFIG* conf)
{
WOLFSSHD_CONFIG* current;
void* heap;
current = conf;
while (current != NULL) {
WOLFSSHD_CONFIG* next = current->next;
heap = current->heap;
FreeString(&current->banner, heap);
FreeString(&current->chrootDir, heap);
FreeString(&current->ciphers, heap);
FreeString(&current->kekAlgos, heap);
FreeString(&current->hostKeyAlgos, heap);
FreeString(&current->listenAddress, heap);
FreeString(&current->authKeysFile, heap);
FreeString(&current->hostKeyFile, heap);
FreeString(&current->hostCertFile, heap);
FreeString(&current->pidFile, heap);
FreeString(&current->userCAKeysFile, heap);
FreeString(&current->forceCmd, heap);
FreeString(&current->usrAppliesTo, heap);
FreeString(&current->groupAppliesTo, heap);
WFREE(current, heap, DYNTYPE_SSHD);
current = next;
}
}
#define MAX_LINE_SIZE 160
typedef struct {
int tag;
const char* name;
} CONFIG_OPTION;
enum {
OPT_AUTH_KEYS_FILE = 0,
OPT_PRIV_SEP = 1,
OPT_PERMIT_EMPTY_PW = 2,
OPT_SUBSYSTEM = 3,
OPT_CHALLENGE_RESPONSE_AUTH = 4,
OPT_USE_PAM = 5,
OPT_X11_FORWARDING = 6,
OPT_PRINT_MOTD = 7,
OPT_ACCEPT_ENV = 8,
OPT_PROTOCOL = 9,
OPT_LOGIN_GRACE_TIME = 10,
OPT_HOST_KEY = 11,
OPT_PASSWORD_AUTH = 12,
OPT_PORT = 13,
OPT_PERMIT_ROOT = 14,
OPT_USE_DNS = 15,
OPT_INCLUDE = 16,
OPT_CHROOT_DIR = 17,
OPT_MATCH = 18,
OPT_FORCE_CMD = 19,
OPT_HOST_CERT = 20,
OPT_TRUSTED_USER_CA_KEYS = 21,
OPT_PIDFILE = 22,
OPT_BANNER = 23,
OPT_PUBKEY_AUTH = 24,
};
enum {
NUM_OPTIONS = 25
};
static const CONFIG_OPTION options[NUM_OPTIONS] = {
{OPT_AUTH_KEYS_FILE, "AuthorizedKeysFile"},
{OPT_PRIV_SEP, "UsePrivilegeSeparation"},
{OPT_PERMIT_EMPTY_PW, "PermitEmptyPasswords"},
{OPT_SUBSYSTEM, "Subsystem"},
{OPT_CHALLENGE_RESPONSE_AUTH, "ChallengeResponseAuthentication"},
{OPT_USE_PAM, "UsePAM"},
{OPT_X11_FORWARDING, "X11Forwarding"},
{OPT_PRINT_MOTD, "PrintMotd"},
{OPT_ACCEPT_ENV, "AcceptEnv"},
{OPT_PROTOCOL, "Protocol"},
{OPT_LOGIN_GRACE_TIME, "LoginGraceTime"},
{OPT_HOST_KEY, "HostKey"},
{OPT_PASSWORD_AUTH, "PasswordAuthentication"},
{OPT_PUBKEY_AUTH, "PubkeyAuthentication"},
{OPT_PORT, "Port"},
{OPT_PERMIT_ROOT, "PermitRootLogin"},
{OPT_USE_DNS, "UseDNS"},
{OPT_INCLUDE, "Include"},
{OPT_CHROOT_DIR, "ChrootDirectory"},
{OPT_MATCH, "Match"},
{OPT_FORCE_CMD, "ForceCommand"},
{OPT_HOST_CERT, "HostCertificate"},
{OPT_TRUSTED_USER_CA_KEYS, "TrustedUserCAKeys"},
{OPT_PIDFILE, "PidFile"},
{OPT_BANNER, "Banner"},
};
/* returns WS_SUCCESS on success */
static int HandlePrivSep(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (WSTRCMP(value, "sandbox") == 0) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Sandbox privilege separation");
conf->usePrivilegeSeparation = WOLFSSHD_PRIV_SANDBOX;
}
else if (WSTRCMP(value, "yes") == 0) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Privilege separation enabled");
conf->usePrivilegeSeparation = WOLFSSHD_PRIV_SEPARAT;
}
else if (WSTRCMP(value, "no") == 0) {
wolfSSH_Log(WS_LOG_INFO,
"[SSHD] Turning off privilege separation!");
conf->usePrivilegeSeparation = WOLFSSHD_PRIV_OFF;
}
else {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Unknown/supported privilege separation!");
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandleLoginGraceTime(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
long num;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
num = GetConfigInt(value, (int)XSTRLEN(value), 1, conf->heap);
if (num < 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Issue getting login grace "
"time");
ret = (int)num;
}
else {
conf->loginTimer = num;
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Setting login grace time to "
"%ld", num);
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandlePermitEmptyPw(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (WSTRCMP(value, "no") == 0) {
conf->permitEmptyPasswords = 0;
}
else if (WSTRCMP(value, "yes") == 0) {
conf->permitEmptyPasswords = 1;
}
else {
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandlePermitRoot(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (WSTRCMP(value, "no") == 0) {
conf->permitRootLogin = 0;
}
else if (WSTRCMP(value, "yes") == 0) {
conf->permitRootLogin = 1;
}
else {
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandlePwAuth(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (WSTRCMP(value, "no") == 0) {
wolfSSH_Log(WS_LOG_INFO, "[SSHD] password authentication disabled");
conf->passwordAuth = 0;
}
else if (WSTRCMP(value, "yes") == 0) {
conf->passwordAuth = 1;
}
else {
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandlePubKeyAuth(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (WSTRCMP(value, "no") == 0) {
wolfSSH_Log(WS_LOG_INFO,
"[SSHD] public key authentication disabled");
conf->pubKeyAuth = 0;
}
else if (WSTRCMP(value, "yes") == 0) {
conf->pubKeyAuth = 1;
}
else {
ret = WS_BAD_ARGUMENT;
}
}
return ret;
}
#define WOLFSSH_PROTOCOL_VERSION 2
/* returns WS_SUCCESS on success */
static int HandleProtocol(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
long portInt;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
portInt = GetConfigInt(value, (int)WSTRLEN(value), 0, conf->heap);
if (portInt <= 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Invalid protocol number: %s.",
value);
ret = WS_BAD_ARGUMENT;
}
else {
if (portInt != WOLFSSH_PROTOCOL_VERSION) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Protocol number %ld not "
"supported.", portInt);
ret = WS_BAD_ARGUMENT;
}
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandlePort(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
long portInt;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
portInt = GetConfigInt(value, (int)WSTRLEN(value), 0, conf->heap);
if (portInt <= 0) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Invalid port number: %s.",
value);
ret = WS_BAD_ARGUMENT;
}
else {
if (portInt <= (word16)-1) {
conf->port = (word16)portInt;
}
else {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Port number %ld too big.",
portInt);
ret = WS_BAD_ARGUMENT;
}
}
}
return ret;
}
/* NOLINTNEXTLINE(misc-no-recursion): bounded by WOLFSSHD_MAX_INCLUDE_DEPTH */
static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value, int depth)
{
const char *ptr;
const char *ptr2;
const char *postfix = NULL;
const char *prefix = NULL;
int prefixLen = 0;
int found = 0;
int ret = WS_SUCCESS;
/* No value, nothing to do */
if (!value || value[0] == '\0') {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
/* Ignore trailing whitespace */
ptr = value + WSTRLEN(value) - 1;
while (ptr != value) {
if (WISSPACE(*ptr)) {
ptr--;
}
else {
break;
}
}
/* Find wildcards */
ptr2 = ptr;
while (ptr2 != value) {
if (*ptr2 == '*') {
/* Wildcard found */
found = 1;
if (ptr != ptr2) {
postfix = ptr2 + 1;
}
break;
}
if (*ptr2 == '/') {
/* Found slash before wildcard directory-wildcards
* not supported */
break;
}
ptr2--;
}
ptr = ptr2;
/* Use wildcard */
if (found) {
#if defined(__unix__) || defined(__unix) || \
(defined(__APPLE__) && defined(__MACH__))
struct dirent *dir;
WDIR d;
char *path = NULL;
char *filepath = (char*)WMALLOC(PATH_MAX, conf->heap, DYNTYPE_PATH);
if (filepath == NULL) {
ret = WS_MEMORY_E;
}
if (ret == WS_SUCCESS) {
/* Back find the full path */
while (ptr2 != value) {
if (*ptr2 == '/') {
break;
}
ptr2--;
}
if (ptr2 != value) {
path = (char*)WMALLOC(ptr2 - value + 1,
conf->heap, DYNTYPE_PATH);
if (path == NULL) {
ret = WS_MEMORY_E;
}
else {
WMEMCPY(path, value, ptr2 - value);
path[ptr2 - value] = '\0';
prefix = ptr2 + 1;
prefixLen = (int)(ptr - ptr2 - 1);
}
}
else {
path = (char*)WMALLOC(2, conf->heap, DYNTYPE_PATH);
if (path == NULL) {
ret = WS_MEMORY_E;
}
else {
WMEMCPY(path, ".", 1);
path[1] = '\0';
prefix = value;
prefixLen = (int)(ptr - value);
}
}
}
if (ret == WS_SUCCESS) {
if (!WOPENDIR(NULL, conf->heap, &d, path)) {
word32 fileCount = 0, fileFilled = 0, i, j;
char** fileNames = NULL;
/* Count up the number of files */
while ((dir = WREADDIR(NULL, &d)) != NULL) {
/* Skip sub-directories */
#if defined(__QNX__) || defined(__QNXNTO__)
struct stat s;
lstat(dir->d_name, &s);
if (!S_ISDIR(s.st_mode))
#else
if (dir->d_type != DT_DIR)
#endif
{
fileCount++;
}
}
WREWINDDIR(NULL, &d);
if (fileCount > 0) {
fileNames = (char**)WMALLOC(fileCount * sizeof(char*),
conf->heap, DYNTYPE_PATH);
if (fileNames == NULL) {
ret = WS_MEMORY_E;
}
else {
/* Zero so any slot not filled by the second pass
* (e.g. files removed from the directory between
* the two passes) is NULL rather than garbage. */
WMEMSET(fileNames, 0, fileCount * sizeof(char*));
}
}
if (ret == WS_SUCCESS) {
i = 0;
while (i < fileCount && (dir = WREADDIR(NULL, &d)) != NULL) {
/* Skip sub-directories */
#if defined(__QNX__) || defined(__QNXNTO__)
struct stat s;
lstat(dir->d_name, &s);
if (!S_ISDIR(s.st_mode))
#else
if (dir->d_type != DT_DIR)
#endif
{
/* Duplicate the name; readdir() may reuse its
* dirent storage on the next call, so the
* pointer cannot be retained across the loop. */
char* nameCopy = WSTRDUP(dir->d_name, conf->heap,
DYNTYPE_PATH);
if (nameCopy == NULL) {
ret = WS_MEMORY_E;
break;
}
/* Insert in string order */
for (j = 0; j < i; j++) {
if (WSTRCMP(nameCopy, fileNames[j]) < 0) {
WMEMMOVE(fileNames+j+1, fileNames+j,
(i - j)*sizeof(char*));
break;
}
}
fileNames[j] = nameCopy;
i++;
}
}
/* Only process slots actually filled by the second
* pass; the directory may have shrunk since the
* count pass. */
fileFilled = i;
for (i = 0; ret == WS_SUCCESS && i < fileFilled; i++) {
/* Check if filename prefix matches */
if (prefixLen > 0) {
if ((int)WSTRLEN(fileNames[i]) <= prefixLen) {
continue;
}
if (WSTRNCMP(fileNames[i], prefix, prefixLen)
!= 0) {
continue;
}
}
if (postfix) {
/* Skip if file is too short */
if (WSTRLEN(fileNames[i]) <= WSTRLEN(postfix)) {
continue;
}
if (WSTRNCMP(fileNames[i] +
WSTRLEN(fileNames[i]) -
WSTRLEN(postfix),
postfix, WSTRLEN(postfix))
!= 0) {
/* Not a match */
continue;
}
}
ret = WSNPRINTF(filepath, PATH_MAX, "%s/%s", path,
fileNames[i]);
if (ret < 0 || ret >= PATH_MAX) {
/* Path is too long for the buffer */
ret = WS_INVALID_PATH_E;
break;
}
ret = ConfigLoad(conf, filepath, depth);
if (ret != WS_SUCCESS) {
break;
}
}
/* Free the duplicated names. fileFilled counts the
* slots actually populated, so every entry below it
* holds a valid pointer. */
for (i = 0; i < fileFilled; i++) {
if (fileNames[i] != NULL) {
WFREE(fileNames[i], conf->heap, DYNTYPE_PATH);
}
}
if (fileNames != NULL) {
WFREE(fileNames, conf->heap, DYNTYPE_PATH);
}
}
WCLOSEDIR(NULL, &d);
}
else {
/* Bad directory */
ret = WS_INVALID_PATH_E;
}
}
if (path != NULL) {
WFREE(path, conf->heap, DYNTYPE_PATH);
}
if (filepath != NULL) {
WFREE(filepath, conf->heap, DYNTYPE_PATH);
}
#else
(void)postfix;
(void)prefixLen;
(void)prefix;
/* Don't support wildcards here */
ret = WS_BAD_ARGUMENT;
#endif
}
else {
ret = ConfigLoad(conf, value, depth);
}
}
return ret;
}
/* returns WS_SUCCESS on success */
static int HandleChrootDir(WOLFSSHD_CONFIG* conf, const char* value)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (conf->chrootDir != NULL) {
FreeString(&conf->chrootDir, conf->heap);
conf->chrootDir = NULL;
}
ret = CreateString(&conf->chrootDir, value,
(int)WSTRLEN(value), conf->heap);
}
return ret;
}
/* Parse the value of a Match directive into the user and group applies-to
* fields of 'config'. The value is a whitespace separated sequence of
* keyword/name pairs, e.g. "User alice Group admins". The token immediately
* following a "User" or "Group" keyword is taken literally as the name and is
* never re-examined as a keyword, so a principal named like the opposite
* keyword (e.g. "Match User Group") is handled by position rather than by a
* substring search. A recognized keyword with no following name (e.g. a bare
* "Match User") is a configuration error so the admin's intent is not silently
* dropped. Unrecognized tokens are ignored to stay lenient toward Match
* criteria that are not yet supported. Returns WS_SUCCESS on success. */
static int ParseMatchCriteria(WOLFSSHD_CONFIG* config, const char* value)
{
int ret = WS_SUCCESS;
const char* pt;
if (config == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
pt = value;
while (ret == WS_SUCCESS && pt != NULL && *pt != '\0') {
const char* tok;
int tokSz;
char** out = NULL;
/* skip separators preceding the keyword token */
while (WISSPACE((unsigned char)*pt)) {
pt++;
}
if (*pt == '\0') {
break;
}
/* read the keyword token */
tok = pt;
while (*pt != '\0' && !WISSPACE((unsigned char)*pt)) {
pt++;
}
tokSz = (int)(pt - tok);
/* map the keyword to its applies-to field; ignore anything else */
if (tokSz == (int)XSTRLEN("User") &&
WSTRNCMP(tok, "User", tokSz) == 0) {
out = &config->usrAppliesTo;
}
else if (tokSz == (int)XSTRLEN("Group") &&
WSTRNCMP(tok, "Group", tokSz) == 0) {
out = &config->groupAppliesTo;
}
if (out != NULL) {
/* skip separators between the keyword and its name */
while (WISSPACE((unsigned char)*pt)) {
pt++;
}
/* the next token is the name, taken literally */
tok = pt;
while (*pt != '\0' && !WISSPACE((unsigned char)*pt)) {
pt++;
}
tokSz = (int)(pt - tok);
if (tokSz == 0) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Match %s directive is missing a name",
(out == &config->usrAppliesTo) ? "User" : "Group");
ret = WS_FATAL_ERROR;
}
if (ret == WS_SUCCESS) {
/* a repeated keyword replaces the earlier value */
if (*out != NULL) {
FreeString(out, config->heap);
}
ret = CreateString(out, tok, tokSz, config->heap);
}
}
}
return ret;
}
/* returns WS_SUCCESS when every selector keyword in 'value' is one that is
* implemented. Only the User and Group selectors are handled. The Match value
* is a whitespace separated list of "keyword argument" pairs; any keyword that
* is not User or Group (Address, Host, LocalAddress, LocalPort, RDomain, ...),
* and a Match with no selector at all (bare "Match", "Match all"), is rejected.
* This also catches mixed forms such as "User alice Address 10.0.0.0/8" where
* the unsupported selector would otherwise be silently dropped. */
static int CheckMatchSelectors(const char* value)
{
int ret = WS_SUCCESS;
int i = 0;
int sz;
int len;
int found = 0;
sz = (value != NULL) ? (int)XSTRLEN(value) : 0;
while (ret == WS_SUCCESS && i < sz) {
/* skip whitespace before the keyword */
i += CountWhitespace(value + i, sz - i, 0);
if (i >= sz) {
break;
}
/* length of the keyword token */
len = CountWhitespace(value + i, sz - i, 1);
if (len == (int)(sizeof("User") - 1) &&
WSTRNCMP(value + i, "User", sizeof("User") - 1) == 0) {
found = 1;
}
else if (len == (int)(sizeof("Group") - 1) &&
WSTRNCMP(value + i, "Group", sizeof("Group") - 1) == 0) {
found = 1;
}
else {
ret = WS_FATAL_ERROR;
}
i += len;
if (ret == WS_SUCCESS) {
/* skip whitespace then the argument token for this keyword */
i += CountWhitespace(value + i, sz - i, 0);
i += CountWhitespace(value + i, sz - i, 1);
}
}
/* a Match with no implemented selector at all is also rejected */
if (ret == WS_SUCCESS && !found) {
ret = WS_FATAL_ERROR;
}
return ret;
}
/* returns WS_SUCCESS on success, on success it update the conf pointed to
* and makes it point to the newly created conf node */
static int HandleMatch(WOLFSSHD_CONFIG** conf, const char* value, int valueSz)
{
WOLFSSHD_CONFIG* newConf = NULL;
int ret = WS_SUCCESS;
if (conf == NULL || *conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
/* Only the User and Group selectors are implemented. Reject any Match
* directive that names an unsupported selector (even when mixed with a
* supported one) or names no selector at all, rather than accepting it and
* silently dropping the unsupported part, which would fail open. */
if (ret == WS_SUCCESS) {
ret = CheckMatchSelectors(value);
if (ret != WS_SUCCESS) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Unsupported Match selector, only User and Group are "
"handled");
}
}
/* create new configure for altered options specific to the match */
if (ret == WS_SUCCESS) {
newConf = wolfSSHD_ConfigCopy(*conf);
if (newConf == NULL) {
ret = WS_MEMORY_E;
}
}
/* parse the User/Group criteria the settings apply to */
if (ret == WS_SUCCESS) {
ret = ParseMatchCriteria(newConf, value);
}
/* @TODO handle , separated user/group list */
/* on failure free the config that will not be added to the list */
if (ret != WS_SUCCESS && newConf != NULL) {
wolfSSHD_ConfigFree(newConf);
newConf = NULL;
}
/* update current config being processed */
if (ret == WS_SUCCESS) {
(*conf)->next = newConf;
(*conf) = newConf;
}
else {
/* newConf was allocated but not linked into the list; free it */
wolfSSHD_ConfigFree(newConf);
}
(void)valueSz;
return ret;
}
/* returns WS_SUCCESS on success */
static int HandleForcedCommand(WOLFSSHD_CONFIG* conf, const char* value,
int valueSz)
{
int ret = WS_SUCCESS;
if (conf == NULL || value == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (conf->forceCmd != NULL) {
FreeString(&conf->forceCmd, conf->heap);
conf->forceCmd = NULL;
}
ret = CreateString(&conf->forceCmd, value, valueSz, conf->heap);
}
(void)valueSz;
return ret;
}
/* returns WS_SUCCESS on success */
/* NOLINTNEXTLINE(misc-no-recursion): bounded by WOLFSSHD_MAX_INCLUDE_DEPTH */
static int HandleConfigOption(WOLFSSHD_CONFIG** conf, int opt,
const char* value, const char* full, int fullSz, int depth)
{
int ret = WS_BAD_ARGUMENT;
switch (opt) {
case OPT_AUTH_KEYS_FILE:
(*conf)->authKeysFileSet = 1;
ret = wolfSSHD_ConfigSetAuthKeysFile(*conf, value);
break;
case OPT_PRIV_SEP:
ret = HandlePrivSep(*conf, value);
break;
case OPT_PERMIT_EMPTY_PW:
ret = HandlePermitEmptyPw(*conf, value);
break;
case OPT_SUBSYSTEM:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_CHALLENGE_RESPONSE_AUTH:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_USE_PAM:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_X11_FORWARDING:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_PRINT_MOTD:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_ACCEPT_ENV:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_PROTOCOL:
/* TODO */
ret = HandleProtocol(*conf, value);
break;
case OPT_LOGIN_GRACE_TIME:
ret = HandleLoginGraceTime(*conf, value);
break;
case OPT_HOST_KEY:
/* TODO: Add logic to check if file exists? */
ret = wolfSSHD_ConfigSetHostKeyFile(*conf, value);
break;
case OPT_HOST_CERT:
/* TODO: Add logic to check if file exists? */
ret = wolfSSHD_ConfigSetHostCertFile(*conf, value);
break;
case OPT_PASSWORD_AUTH:
ret = HandlePwAuth(*conf, value);
break;
case OPT_PUBKEY_AUTH:
ret = HandlePubKeyAuth(*conf, value);
break;
case OPT_PORT:
ret = HandlePort(*conf, value);
break;
case OPT_PERMIT_ROOT:
ret = HandlePermitRoot(*conf, value);
break;
case OPT_USE_DNS:
/* TODO */
ret = WS_SUCCESS;
break;
case OPT_INCLUDE:
ret = HandleInclude(*conf, value, depth);
break;
case OPT_CHROOT_DIR:
ret = HandleChrootDir(*conf, value);
break;
case OPT_MATCH:
/* makes new config and appends it to the list */
ret = HandleMatch(conf, full, fullSz);
break;
case OPT_FORCE_CMD:
ret = HandleForcedCommand(*conf, full, fullSz);
break;
case OPT_TRUSTED_USER_CA_KEYS:
/* TODO: Add logic to check if file exists? */
ret = wolfSSHD_ConfigSetUserCAKeysFile(*conf, value);
break;
case OPT_PIDFILE:
ret = SetFileString(&(*conf)->pidFile, value, (*conf)->heap);
break;
case OPT_BANNER:
ret = SetFileString(&(*conf)->banner, value, (*conf)->heap);
break;
default:
break;
}
return ret;
}
/* helper function to count white spaces, returns the number of white spaces on
* success */
static int CountWhitespace(const char* in, int inSz, byte inv)
{
int i = 0;
if (in != NULL) {
for (; i < inSz; ++i) {
if (inv) {
if (WISSPACE(in[i])) {
break;
}
}
else {
if (!WISSPACE(in[i])) {
break;
}
}
}
}
return i;
}
/* returns WS_SUCCESS on success
* Fails if any option is found that is unknown/unsupported
* Match command will create new configs for specific matching cases
*/
/* NOLINTNEXTLINE(misc-no-recursion): bounded by WOLFSSHD_MAX_INCLUDE_DEPTH */
WOLFSSHD_STATIC int ParseConfigLine(WOLFSSHD_CONFIG** conf, const char* l,
int lSz, int depth)
{
int ret = WS_BAD_ARGUMENT;
int sz = 0;
char tmp[MAX_FILENAME_SZ];
int idx;
const CONFIG_OPTION* found = NULL;
for (idx = 0; idx < NUM_OPTIONS; ++idx) {
sz = (int)WSTRLEN(options[idx].name);
if (lSz >= sz && WSTRNCMP(l, options[idx].name, sz) == 0) {
found = &options[idx];
break;
}
}
if (found != NULL) {
/*
* Count leading and trailing whitespace. Use that information to cut
* out just the string itself when creating tmp.
*/
idx = sz;
idx += CountWhitespace(l + idx, lSz - sz, 0);
sz = CountWhitespace(l + idx, lSz - idx, 1);
if (sz >= MAX_FILENAME_SZ) {
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Filename too long.");
ret = WS_FATAL_ERROR;
}
else {
WMEMCPY(tmp, l + idx, sz);
tmp[sz] = 0;
ret = HandleConfigOption(conf,
found->tag, tmp, l + idx, lSz - idx, depth);
}
}
else {
#ifdef WOLFSSH_IGNORE_UNKNOWN_CONFIG
wolfSSH_Log(WS_LOG_DEBUG, "[SSHD] ignoring config line %s.", l);
ret = WS_SUCCESS;
#else
wolfSSH_Log(WS_LOG_ERROR, "[SSHD] Error parsing config line.");
ret = WS_FATAL_ERROR;
#endif
}
return ret;
}
/* parses and loads in the given configuration file 'filename'
* returns WS_SUCCESS on success
*/
int wolfSSHD_ConfigLoad(WOLFSSHD_CONFIG* conf, const char* filename)
{
return ConfigLoad(conf, filename, 0);
}
/* NOLINTNEXTLINE(misc-no-recursion): bounded by WOLFSSHD_MAX_INCLUDE_DEPTH */
static int ConfigLoad(WOLFSSHD_CONFIG* conf, const char* filename, int depth)
{
WFILE *f;
WOLFSSHD_CONFIG* currentConfig;
int ret = WS_SUCCESS;
char buf[MAX_LINE_SIZE];
const char* current;
if (conf == NULL || filename == NULL)
return BAD_FUNC_ARG;
if (depth >= WOLFSSHD_MAX_INCLUDE_DEPTH) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Include depth (%d) exceeded loading %s",
WOLFSSHD_MAX_INCLUDE_DEPTH, filename);
return WS_BAD_ARGUMENT;
}
if (WFOPEN(NULL, &f, filename, "rb") != 0) {
wolfSSH_Log(WS_LOG_ERROR, "Unable to open SSHD config file %s",
filename);
return BAD_FUNC_ARG;
}
wolfSSH_Log(WS_LOG_INFO, "[SSHD] parsing config file %s", filename);
depth++;
currentConfig = conf;
while ((current = XFGETS(buf, MAX_LINE_SIZE, f)) != NULL) {
int currentSz = (int)XSTRLEN(current);
/* remove leading spaces and tabs */
while (currentSz > 0 &&
(current[0] == ' ' || current[0] == '\t')) {
currentSz = currentSz - 1;
current = current + 1;
}
if (currentSz <= 2) { /* \n or \r\n */
continue; /* empty line */
}
if (current[0] == '#') {
continue; /* commented out line */
}
ret = ParseConfigLine(&currentConfig, current, currentSz, depth);
if (ret != WS_SUCCESS) {
fprintf(stderr, "Unable to parse config line : %s\n", current);
break;
}
}
WFCLOSE(NULL, f);
return ret;
}
/* returns the config associated with the user */
WOLFSSHD_CONFIG* wolfSSHD_GetUserConf(const WOLFSSHD_CONFIG* conf,
const char* usr, const char* grp, const char* host,
const char* localAdr, word16* localPort, const char* RDomain,
const char* adr)
{
WOLFSSHD_CONFIG* ret;
WOLFSSHD_CONFIG* current;
/* default to return head of list */
ret = current = (WOLFSSHD_CONFIG*)conf;
while (current != NULL) {
/* compare current configs user */
if (usr != NULL && current->usrAppliesTo != NULL) {
if (XSTRCMP(current->usrAppliesTo, usr) == 0) {
ret = current;
break;
}
}
/* compare current configs group */
if (grp != NULL && current->groupAppliesTo != NULL) {
if (XSTRCMP(current->groupAppliesTo, grp) == 0) {
ret = current;
break;
}
}
current = current->next;
}
/* @TODO */
(void)host;
(void)localAdr;
(void)localPort;
(void)RDomain;
(void)adr;
return ret;
}
char* wolfSSHD_ConfigGetForcedCmd(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->forceCmd;
}
return ret;
}
char* wolfSSHD_ConfigGetAuthKeysFile(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->authKeysFile;
}
return ret;
}
/* returns 1 if the authorized keys file was set and 0 if not */
int wolfSSHD_ConfigGetAuthKeysFileSet(const WOLFSSHD_CONFIG* conf)
{
int ret = 0;
if (conf != NULL) {
ret = conf->authKeysFileSet;
}
return ret;
}
int wolfSSHD_ConfigSetAuthKeysFile(WOLFSSHD_CONFIG* conf, const char* file)
{
int ret = WS_SUCCESS;
if (conf == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (conf->authKeysFile != NULL) {
FreeString(&conf->authKeysFile, conf->heap);
conf->authKeysFile = NULL;
}
if (file != NULL) {
ret = CreateString(&conf->authKeysFile, file,
(int)WSTRLEN(file), conf->heap);
}
}
return ret;
}
char* wolfSSHD_ConfigGetBanner(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->banner;
}
return ret;
}
char* wolfSSHD_ConfigGetChroot(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->chrootDir;
}
return ret;
}
char* wolfSSHD_ConfigGetHostKeyFile(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->hostKeyFile;
}
return ret;
}
char* wolfSSHD_ConfigGetHostCertFile(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->hostCertFile;
}
return ret;
}
char* wolfSSHD_ConfigGetUserCAKeysFile(const WOLFSSHD_CONFIG* conf)
{
char* ret = NULL;
if (conf != NULL) {
ret = conf->userCAKeysFile;
}
return ret;
}
static int SetFileString(char** dst, const char* src, void* heap)
{
int ret = WS_SUCCESS;
if (dst == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
if (*dst != NULL) {
FreeString(dst, heap);
*dst = NULL;
}
if (src != NULL) {
ret = CreateString(dst, src, (int)WSTRLEN(src), heap);
}
}
return ret;
}
int wolfSSHD_ConfigSetHostKeyFile(WOLFSSHD_CONFIG* conf, const char* file)
{
int ret = WS_SUCCESS;
if (conf == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
ret = SetFileString(&conf->hostKeyFile, file, conf->heap);
}
return ret;
}
int wolfSSHD_ConfigSetHostCertFile(WOLFSSHD_CONFIG* conf, const char* file)
{
int ret = WS_SUCCESS;
if (conf == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
ret = SetFileString(&conf->hostCertFile, file, conf->heap);
}
return ret;
}
int wolfSSHD_ConfigSetUserCAKeysFile(WOLFSSHD_CONFIG* conf, const char* file)
{
int ret = WS_SUCCESS;
if (conf == NULL) {
ret = WS_BAD_ARGUMENT;
}
if (ret == WS_SUCCESS) {
ret = SetFileString(&conf->userCAKeysFile, file, conf->heap);
}
return ret;
}
word16 wolfSSHD_ConfigGetPort(const WOLFSSHD_CONFIG* conf)
{
word16 ret = 0;
if (conf != NULL) {
ret = conf->port;
}
return ret;
}
byte wolfSSHD_ConfigGetPermitEmptyPw(const WOLFSSHD_CONFIG* conf)
{
byte ret = 0;
if (conf != NULL) {
ret = conf->permitEmptyPasswords;
}
return ret;
}
byte wolfSSHD_ConfigGetPrivilegeSeparation(const WOLFSSHD_CONFIG* conf)
{
byte ret = 0;
if (conf != NULL) {
ret = conf->usePrivilegeSeparation;
}
return ret;
}
byte wolfSSHD_ConfigGetPwAuth(const WOLFSSHD_CONFIG* conf)
{
byte ret = 0;
if (conf != NULL) {
ret = conf->passwordAuth;
}
return ret;
}
byte wolfSSHD_ConfigGetPubKeyAuth(const WOLFSSHD_CONFIG* conf)
{
byte ret = 0;
if (conf != NULL) {
ret = conf->pubKeyAuth;
}
return ret;
}
byte wolfSSHD_ConfigGetPermitRoot(const WOLFSSHD_CONFIG* conf)
{
byte ret = 0;
if (conf != NULL) {
ret = conf->permitRootLogin;
}
return ret;
}
long wolfSSHD_ConfigGetGraceTime(const WOLFSSHD_CONFIG* conf)
{
long ret = WS_BAD_ARGUMENT;
if (conf != NULL) {
ret = conf->loginTimer;
}
return ret;
}
/* Used to save out the PID of SSHD to a file */
void wolfSSHD_ConfigSavePID(const WOLFSSHD_CONFIG* conf)
{
FILE* f;
char buf[12]; /* large enough to hold 'int' type with null terminator */
if (conf->pidFile != NULL) {
WMEMSET(buf, 0, sizeof(buf));
if (WFOPEN(NULL, &f, conf->pidFile, "wb") == 0) {
#ifndef WIN32
WSNPRINTF(buf, sizeof(buf), "%d", getpid());
#else
WSNPRINTF(buf, sizeof(buf), "%d", _getpid());
#endif
WFWRITE(NULL, buf, 1, WSTRLEN(buf), f);
WFCLOSE(NULL, f);
}
}
}
#endif /* WOLFSSH_SSHD */
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