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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2000-2005, 2007-2023
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if defined(HAVE_STDINT_H)
# include <stdint.h>
#elif defined(HAVE_INTTYPES_H)
# include <inttypes.h>
#endif
#ifdef HAVE_LOGIN_CAP_H
# include <login_cap.h>
# ifndef LOGIN_SETENV
# define LOGIN_SETENV 0
# endif
#endif /* HAVE_LOGIN_CAP_H */
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <pwd.h>
#include <sudoers.h>
/*
* Flags used in rebuild_env()
*/
#undef DID_TERM
#define DID_TERM 0x00000001
#undef DID_PATH
#define DID_PATH 0x00000002
#undef DID_HOME
#define DID_HOME 0x00000004
#undef DID_SHELL
#define DID_SHELL 0x00000008
#undef DID_LOGNAME
#define DID_LOGNAME 0x00000010
#undef DID_USER
#define DID_USER 0x00000020
#undef DID_LOGIN
#define DID_LOGIN 0x00000040
#undef DID_MAIL
#define DID_MAIL 0x00000080
#undef DID_MAX
#define DID_MAX 0x0000ffff
#undef KEPT_TERM
#define KEPT_TERM 0x00010000
#undef KEPT_PATH
#define KEPT_PATH 0x00020000
#undef KEPT_HOME
#define KEPT_HOME 0x00040000
#undef KEPT_SHELL
#define KEPT_SHELL 0x00080000
#undef KEPT_LOGNAME
#define KEPT_LOGNAME 0x00100000
#undef KEPT_USER
#define KEPT_USER 0x00200000
#undef KEPT_LOGIN
#define KEPT_LOGIN 0x00400000
#undef KEPT_MAIL
#define KEPT_MAIL 0x00800000
#undef KEPT_MAX
#define KEPT_MAX 0xffff0000
/*
* AIX sets the LOGIN environment variable too.
*/
#ifdef _AIX
# define KEPT_USER_VARIABLES (KEPT_LOGIN|KEPT_LOGNAME|KEPT_USER)
#else
# define KEPT_USER_VARIABLES (KEPT_LOGNAME|KEPT_USER)
#endif
/*
* Functions to open, close and parse an environment file, either
* a system file such as /etc/environment or one specified in sudoers.
*/
struct sudoers_env_file {
void * (*open)(const char *);
void (*close)(void *);
char * (*next)(void *, int *);
};
/*
* State for a local environment file.
*/
struct env_file_local {
FILE *fp;
char *line;
size_t linesize;
};
struct environment {
char **envp; /* pointer to the new environment */
char **old_envp; /* pointer the old environment we allocated */
size_t env_size; /* size of new_environ in char **'s */
size_t env_len; /* number of slots used, not counting NULL */
};
/*
* Copy of the sudo-managed environment.
*/
static struct environment env;
/*
* Default table of "bad" variables to remove from the environment.
* XXX - how to omit TERMCAP if it starts with '/'?
*/
static const char *initial_badenv_table[] = {
"IFS",
"CDPATH",
"LOCALDOMAIN",
"RES_OPTIONS",
"HOSTALIASES",
"NLSPATH",
"PATH_LOCALE",
"LD_*",
"_RLD*",
#ifdef __hpux
"SHLIB_PATH",
#endif /* __hpux */
#ifdef _AIX
"LDR_*",
"LIBPATH",
"AUTHSTATE",
#endif
#ifdef __APPLE__
"DYLD_*",
#endif
#ifdef HAVE_KERB5
"KRB5_CONFIG*",
"KRB5_KTNAME",
#endif /* HAVE_KERB5 */
#ifdef HAVE_SECURID
"VAR_ACE",
"USR_ACE",
"DLC_ACE",
#endif /* HAVE_SECURID */
"TERMINFO", /* terminfo, exclusive path to terminfo files */
"TERMINFO_DIRS", /* terminfo, path(s) to terminfo files */
"TERMPATH", /* termcap, path(s) to termcap files */
"TERMCAP", /* XXX - only if it starts with '/' */
"ENV", /* ksh, file to source before script runs */
"BASH_ENV", /* bash, file to source before script runs */
"PS4", /* bash, prefix for lines in xtrace mode */
"GLOBIGNORE", /* bash, globbing patterns to ignore */
"BASHOPTS", /* bash, initial "shopt -s" options */
"SHELLOPTS", /* bash, initial "set -o" options */
"JAVA_TOOL_OPTIONS", /* java, extra command line options */
"PERLIO_DEBUG", /* perl, debugging output file */
"PERLLIB", /* perl, search path for modules/includes */
"PERL5LIB", /* perl 5, search path for modules/includes */
"PERL5OPT", /* perl 5, extra command line options */
"PERL5DB", /* perl 5, command used to load debugger */
"FPATH", /* ksh, search path for functions */
"NULLCMD", /* zsh, command for null file redirection */
"READNULLCMD", /* zsh, command for null file redirection */
"ZDOTDIR", /* zsh, search path for dot files */
"TMPPREFIX", /* zsh, prefix for temporary files */
"PYTHONHOME", /* python, module search path */
"PYTHONPATH", /* python, search path */
"PYTHONINSPECT", /* python, allow inspection */
"PYTHONUSERBASE", /* python, per user site-packages directory */
"RUBYLIB", /* ruby, library load path */
"RUBYOPT", /* ruby, extra command line options */
"*=()*", /* bash functions */
NULL
};
/*
* Default table of variables to check for '%' and '/' characters.
*/
static const char *initial_checkenv_table[] = {
"COLORTERM",
"LANG",
"LANGUAGE",
"LC_*",
"LINGUAS",
"TERM",
"TZ",
NULL
};
/*
* Default table of variables to preserve in the environment.
*/
static const char *initial_keepenv_table[] = {
"COLORS",
"DISPLAY",
"HOSTNAME",
"KRB5CCNAME",
"LS_COLORS",
"PATH",
"PS1",
"PS2",
"XAUTHORITY",
"XAUTHORIZATION",
"XDG_CURRENT_DESKTOP",
NULL
};
/*
* Free our copy (or copies) of the environment.
* This function is only safe to call after the command has executed.
*/
void
env_free(void)
{
sudoers_gc_remove(GC_PTR, env.envp);
free(env.envp);
sudoers_gc_remove(GC_PTR, env.old_envp);
free(env.old_envp);
memset(&env, 0, sizeof(env));
}
/*
* Initialize env based on envp.
*/
bool
env_init(char * const envp[])
{
char * const *ep;
size_t len;
debug_decl(env_init, SUDOERS_DEBUG_ENV);
if (envp == NULL) {
/* Free the old envp we allocated, if any. */
sudoers_gc_remove(GC_PTR, env.old_envp);
free(env.old_envp);
/*
* Reset to initial state but keep a pointer to what we allocated
* since it will be passed to execve(2).
*/
env.old_envp = env.envp;
env.envp = NULL;
env.env_size = 0;
env.env_len = 0;
} else {
/* Make private copy of envp. */
for (ep = envp; *ep != NULL; ep++)
continue;
len = (size_t)(ep - envp);
env.env_len = len;
env.env_size = len + 1 + 128;
env.envp = reallocarray(NULL, env.env_size, sizeof(char *));
if (env.envp == NULL) {
env.env_size = 0;
env.env_len = 0;
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_bool(false);
}
sudoers_gc_add(GC_PTR, env.envp);
#ifdef ENV_DEBUG
memset(env.envp, 0, env.env_size * sizeof(char *));
#endif
memcpy(env.envp, envp, len * sizeof(char *));
env.envp[len] = NULL;
/* Free the old envp we allocated, if any. */
sudoers_gc_remove(GC_PTR, env.old_envp);
free(env.old_envp);
env.old_envp = NULL;
}
debug_return_bool(true);
}
/*
* Getter for private copy of the environment.
*/
char **
env_get(void)
{
return env.envp;
}
/*
* Swap the old and new copies of the environment.
*/
bool
env_swap_old(void)
{
char **old_envp;
if (env.old_envp == NULL)
return false;
old_envp = env.old_envp;
env.old_envp = env.envp;
env.envp = old_envp;
return true;
}
/*
* Similar to putenv(3) but operates on sudo's private copy of the
* environment (not environ) and it always overwrites. The dupcheck param
* determines whether we need to verify that the variable is not already set.
* Will only overwrite an existing variable if overwrite is set.
* Does not include warnings or debugging to avoid recursive calls.
*/
int
sudo_putenv_nodebug(char *str, bool dupcheck, bool overwrite)
{
char **ep;
const char *equal;
bool found = false;
/* Some putenv(3) implementations check for NULL. */
if (str == NULL) {
errno = EINVAL;
return -1;
}
/* The string must contain a '=' char but not start with one. */
equal = strchr(str, '=');
if (equal == NULL || equal == str) {
errno = EINVAL;
return -1;
}
/* Make sure there is room for the new entry plus a NULL. */
if (env.env_size > 2 && env.env_len > env.env_size - 2) {
char **nenvp;
size_t nsize;
if (env.env_size > SIZE_MAX - 128) {
sudo_warnx_nodebug(U_("internal error, %s overflow"),
"sudo_putenv_nodebug");
errno = EOVERFLOW;
return -1;
}
nsize = env.env_size + 128;
if (nsize > SIZE_MAX / sizeof(char *)) {
sudo_warnx_nodebug(U_("internal error, %s overflow"),
"sudo_putenv_nodebug");
errno = EOVERFLOW;
return -1;
}
sudoers_gc_remove(GC_PTR, env.envp);
nenvp = reallocarray(env.envp, nsize, sizeof(char *));
if (nenvp == NULL) {
sudoers_gc_add(GC_PTR, env.envp);
return -1;
}
sudoers_gc_add(GC_PTR, nenvp);
env.envp = nenvp;
env.env_size = nsize;
#ifdef ENV_DEBUG
memset(env.envp + env.env_len, 0,
(env.env_size - env.env_len) * sizeof(char *));
#endif
}
#ifdef ENV_DEBUG
if (env.envp[env.env_len] != NULL) {
errno = EINVAL;
return -1;
}
#endif
if (dupcheck) {
size_t len = (size_t)(equal - str) + 1;
for (ep = env.envp; *ep != NULL; ep++) {
if (strncmp(str, *ep, len) == 0) {
if (overwrite)
*ep = str;
found = true;
break;
}
}
/* Prune out extra instances of the variable we just overwrote. */
if (found && overwrite) {
while (*++ep != NULL) {
if (strncmp(str, *ep, len) == 0) {
char **cur = ep;
while ((*cur = *(cur + 1)) != NULL)
cur++;
ep--;
}
}
env.env_len = (size_t)(ep - env.envp);
}
}
if (!found) {
ep = env.envp + env.env_len;
env.env_len++;
*ep++ = str;
*ep = NULL;
}
return 0;
}
/*
* Similar to putenv(3) but operates on sudo's private copy of the
* environment (not environ) and it always overwrites. The dupcheck param
* determines whether we need to verify that the variable is not already set.
* Will only overwrite an existing variable if overwrite is set.
*/
static int
sudo_putenv(char *str, bool dupcheck, bool overwrite)
{
int ret;
debug_decl(sudo_putenv, SUDOERS_DEBUG_ENV);
sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_putenv: %s", str);
ret = sudo_putenv_nodebug(str, dupcheck, overwrite);
if (ret == -1) {
#ifdef ENV_DEBUG
if (env.envp[env.env_len] != NULL) {
sudo_warnx("%s",
U_("sudo_putenv: corrupted envp, length mismatch"));
}
#endif
}
debug_return_int(ret);
}
/*
* Similar to setenv(3) but operates on a private copy of the environment.
* The dupcheck param determines whether we need to verify that the variable
* is not already set.
*/
static int
sudo_setenv2(const char *var, const char *val, bool dupcheck, bool overwrite)
{
char *estring;
size_t esize;
int ret = -1;
debug_decl(sudo_setenv2, SUDOERS_DEBUG_ENV);
esize = strlen(var) + 1 + strlen(val) + 1;
if ((estring = malloc(esize)) == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
debug_return_int(-1);
}
/* Build environment string and insert it. */
if (strlcpy(estring, var, esize) >= esize ||
strlcat(estring, "=", esize) >= esize ||
strlcat(estring, val, esize) >= esize) {
sudo_warnx(U_("internal error, %s overflow"), __func__);
errno = EOVERFLOW;
} else {
ret = sudo_putenv(estring, dupcheck, overwrite);
}
if (ret == -1)
free(estring);
else
sudoers_gc_add(GC_PTR, estring);
debug_return_int(ret);
}
/*
* Similar to setenv(3) but operates on a private copy of the environment.
*/
int
sudo_setenv(const char *var, const char *val, int overwrite)
{
return sudo_setenv2(var, val, true, (bool)overwrite);
}
/*
* Similar to unsetenv(3) but operates on a private copy of the environment.
* Does not include warnings or debugging to avoid recursive calls.
*/
int
sudo_unsetenv_nodebug(const char *var)
{
char **ep = env.envp;
size_t len;
if (ep == NULL || var == NULL || *var == '\0' || strchr(var, '=') != NULL) {
errno = EINVAL;
return -1;
}
len = strlen(var);
while (*ep != NULL) {
if (strncmp(var, *ep, len) == 0 && (*ep)[len] == '=') {
/* Found it; shift remainder + NULL over by one. */
char **cur = ep;
while ((*cur = *(cur + 1)) != NULL)
cur++;
env.env_len--;
/* Keep going, could be multiple instances of the var. */
} else {
ep++;
}
}
return 0;
}
/*
* Similar to unsetenv(3) but operates on a private copy of the environment.
*/
int
sudo_unsetenv(const char *name)
{
int ret;
debug_decl(sudo_unsetenv, SUDOERS_DEBUG_ENV);
sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_unsetenv: %s", name);
ret = sudo_unsetenv_nodebug(name);
debug_return_int(ret);
}
/*
* Similar to getenv(3) but operates on a private copy of the environment.
* Does not include warnings or debugging to avoid recursive calls.
*/
char *
sudo_getenv_nodebug(const char *name)
{
char **ep, *val = NULL;
size_t namelen = 0;
if (env.env_len != 0) {
/* For BSD compatibility, treat '=' in name like end of string. */
while (name[namelen] != '\0' && name[namelen] != '=')
namelen++;
for (ep = env.envp; *ep != NULL; ep++) {
if (strncmp(*ep, name, namelen) == 0 && (*ep)[namelen] == '=') {
val = *ep + namelen + 1;
break;
}
}
}
return val;
}
/*
* Similar to getenv(3) but operates on a private copy of the environment.
*/
char *
sudo_getenv(const char *name)
{
char *val;
debug_decl(sudo_getenv, SUDOERS_DEBUG_ENV);
sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_getenv: %s", name);
val = sudo_getenv_nodebug(name);
debug_return_str(val);
}
/*
* Check for var against patterns in the specified environment list.
* Returns true if the variable was found, else false.
*/
static bool
matches_env_list(const char *var, struct list_members *list, bool *full_match)
{
struct list_member *cur;
bool is_logname = false;
debug_decl(matches_env_list, SUDOERS_DEBUG_ENV);
switch (*var) {
case 'L':
if (strncmp(var, "LOGNAME=", 8) == 0)
is_logname = true;
#ifdef _AIX
else if (strncmp(var, "LOGIN=", 6) == 0)
is_logname = true;
#endif
break;
case 'U':
if (strncmp(var, "USER=", 5) == 0)
is_logname = true;
break;
}
if (is_logname) {
/*
* We treat LOGIN, LOGNAME and USER specially.
* If one is preserved/deleted we want to preserve/delete them all.
*/
SLIST_FOREACH(cur, list, entries) {
if (matches_env_pattern(cur->value, "LOGNAME", full_match) ||
#ifdef _AIX
matches_env_pattern(cur->value, "LOGIN", full_match) ||
#endif
matches_env_pattern(cur->value, "USER", full_match))
debug_return_bool(true);
}
} else {
SLIST_FOREACH(cur, list, entries) {
if (matches_env_pattern(cur->value, var, full_match))
debug_return_bool(true);
}
}
debug_return_bool(false);
}
/*
* Check the env_delete blocklist.
* Returns true if the variable was found, else false.
*/
static bool
matches_env_delete(const char *var)
{
bool full_match; /* unused */
debug_decl(matches_env_delete, SUDOERS_DEBUG_ENV);
/* Skip anything listed in env_delete. */
debug_return_bool(matches_env_list(var, &def_env_delete, &full_match));
}
/*
* Verify the TZ environment variable is safe.
* On many systems it is possible to set this to a pathname.
*/
static bool
tz_is_safe(const char *tzval)
{
const char *cp;
char lastch;
debug_decl(tz_is_safe, SUDOERS_DEBUG_ENV);
/* tzcode treats a value beginning with a ':' as a path. */
if (tzval[0] == ':')
tzval++;
/* Reject fully-qualified TZ that doesn't being with the zoneinfo dir. */
if (tzval[0] == '/') {
#ifdef _PATH_ZONEINFO
if (strncmp(tzval, _PATH_ZONEINFO, sizeof(_PATH_ZONEINFO) - 1) != 0 ||
tzval[sizeof(_PATH_ZONEINFO) - 1] != '/')
debug_return_bool(false);
#else
/* Assume the worst. */
debug_return_bool(false);
#endif
}
/*
* Make sure TZ only contains printable non-space characters
* and does not contain a '..' path element.
*/
lastch = '/';
for (cp = tzval; *cp != '\0'; cp++) {
if (isspace((unsigned char)*cp) || !isprint((unsigned char)*cp))
debug_return_bool(false);
if (lastch == '/' && cp[0] == '.' && cp[1] == '.' &&
(cp[2] == '/' || cp[2] == '\0'))
debug_return_bool(false);
lastch = *cp;
}
/* Reject extra long TZ values (even if not a path). */
if ((size_t)(cp - tzval) >= PATH_MAX)
debug_return_bool(false);
debug_return_bool(true);
}
/*
* Apply the env_check list.
* Returns true if the variable is allowed, false if denied
* or -1 if no match.
*/
static int
matches_env_check(const char *var, bool *full_match)
{
int keepit = -1;
debug_decl(matches_env_check, SUDOERS_DEBUG_ENV);
/* Skip anything listed in env_check that includes '/' or '%'. */
if (matches_env_list(var, &def_env_check, full_match)) {
if (strncmp(var, "TZ=", 3) == 0) {
/* Special case for TZ */
keepit = tz_is_safe(var + 3);
} else {
const char *val = strchr(var, '=');
if (val != NULL)
keepit = !strpbrk(val + 1, "/%");
}
}
debug_return_int(keepit);
}
/*
* Check the env_keep list.
* Returns true if the variable is allowed else false.
*/
static bool
matches_env_keep(const struct sudoers_context *ctx, const char *var,
bool *full_match)
{
bool keepit = false;
debug_decl(matches_env_keep, SUDOERS_DEBUG_ENV);
/* Preserve SHELL variable for "sudo -s". */
if (ISSET(ctx->mode, MODE_SHELL) && strncmp(var, "SHELL=", 6) == 0) {
keepit = true;
} else if (matches_env_list(var, &def_env_keep, full_match)) {
keepit = true;
}
debug_return_bool(keepit);
}
/*
* Look up var in the env_delete and env_check.
* Returns true if we should delete the variable, else false.
*/
static bool
env_should_delete(const char *var)
{
int delete_it;
bool full_match = false;
debug_decl(env_should_delete, SUDOERS_DEBUG_ENV);
delete_it = matches_env_delete(var);
if (!delete_it)
delete_it = matches_env_check(var, &full_match) == false;
sudo_debug_printf(SUDO_DEBUG_INFO, "delete %s: %s",
var, delete_it ? "YES" : "NO");
debug_return_bool(delete_it);
}
/*
* Lookup var in the env_check and env_keep lists.
* Returns true if the variable is allowed else false.
*/
static bool
env_should_keep(const struct sudoers_context *ctx, const char *var)
{
int keepit;
bool full_match = false;
const char *cp;
debug_decl(env_should_keep, SUDOERS_DEBUG_ENV);
keepit = matches_env_check(var, &full_match);
if (keepit == -1)
keepit = matches_env_keep(ctx, var, &full_match);
/* Skip bash functions unless we matched on the value as well as name. */
if (keepit && !full_match) {
if ((cp = strchr(var, '=')) != NULL) {
if (strncmp(cp, "=() ", 4) == 0)
keepit = false;
}
}
sudo_debug_printf(SUDO_DEBUG_INFO, "keep %s: %s",
var, keepit == true ? "YES" : "NO");
debug_return_bool(keepit == true);
}
#ifdef HAVE_PAM
/*
* Merge another environment with our private copy.
* Only overwrite an existing variable if it is not
* being preserved from the user's environment.
* Returns true on success or false on failure.
*/
bool
env_merge(const struct sudoers_context *ctx, char * const envp[])
{
char * const *ep;
bool ret = true;
debug_decl(env_merge, SUDOERS_DEBUG_ENV);
for (ep = envp; *ep != NULL; ep++) {
/* XXX - avoid checking value here, should only check name */
bool overwrite = def_env_reset ? !env_should_keep(ctx, *ep) : env_should_delete(*ep);
if (sudo_putenv(*ep, true, overwrite) == -1) {
/* XXX cannot undo on failure */
ret = false;
break;
}
}
debug_return_bool(ret);
}
#endif /* HAVE_PAM */
static void
env_update_didvar(const char *ep, unsigned int *didvar)
{
switch (*ep) {
case 'H':
if (strncmp(ep, "HOME=", 5) == 0)
SET(*didvar, DID_HOME);
break;
case 'L':
#ifdef _AIX
if (strncmp(ep, "LOGIN=", 8) == 0)
SET(*didvar, DID_LOGIN);
#endif
if (strncmp(ep, "LOGNAME=", 8) == 0)
SET(*didvar, DID_LOGNAME);
break;
case 'M':
if (strncmp(ep, "MAIL=", 5) == 0)
SET(*didvar, DID_MAIL);
break;
case 'P':
if (strncmp(ep, "PATH=", 5) == 0)
SET(*didvar, DID_PATH);
break;
case 'S':
if (strncmp(ep, "SHELL=", 6) == 0)
SET(*didvar, DID_SHELL);
break;
case 'T':
if (strncmp(ep, "TERM=", 5) == 0)
SET(*didvar, DID_TERM);
break;
case 'U':
if (strncmp(ep, "USER=", 5) == 0)
SET(*didvar, DID_USER);
break;
}
}
#define CHECK_PUTENV(a, b, c) do { \
if (sudo_putenv((char *)(a), (b), (c)) == -1) { \
goto bad; \
} \
} while (0)
#define CHECK_SETENV2(a, b, c, d) do { \
if (sudo_setenv2((char *)(a), (b), (c), (d)) == -1) { \
goto bad; \
} \
} while (0)
/*
* Build a new environment and either clear potentially dangerous
* variables from the old one or start with a clean slate.
* Also adds sudo-specific variables (SUDO_*).
* Returns true on success or false on failure.
*/
bool
rebuild_env(const struct sudoers_context *ctx)
{
char **ep, *cp, *ps1;
char idbuf[STRLEN_MAX_UNSIGNED(uid_t) + 1];
unsigned int didvar;
bool reset_home = false;
int len;
debug_decl(rebuild_env, SUDOERS_DEBUG_ENV);
/*
* Either clean out the environment or reset to a safe default.
*/
ps1 = NULL;
didvar = 0;
env.env_len = 0;
env.env_size = 128;
sudoers_gc_remove(GC_PTR, env.old_envp);
free(env.old_envp);
env.old_envp = env.envp;
env.envp = reallocarray(NULL, env.env_size, sizeof(char *));
if (env.envp == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
env.env_size = 0;
goto bad;
}
sudoers_gc_add(GC_PTR, env.envp);
#ifdef ENV_DEBUG
memset(env.envp, 0, env.env_size * sizeof(char *));
#else
env.envp[0] = NULL;
#endif
/* Reset HOME based on target user if configured to. */
if (ISSET(ctx->mode, MODE_RUN)) {
if (def_always_set_home ||
ISSET(ctx->mode, MODE_RESET_HOME | MODE_LOGIN_SHELL) ||
(ISSET(ctx->mode, MODE_SHELL) && def_set_home))
reset_home = true;
}
if (def_env_reset || ISSET(ctx->mode, MODE_LOGIN_SHELL)) {
/*
* If starting with a fresh environment, initialize it based on
* /etc/environment or login.conf. For "sudo -i" we want those
* variables to override the invoking user's environment, so we
* defer reading them until later.
*/
if (!ISSET(ctx->mode, MODE_LOGIN_SHELL)) {
#ifdef HAVE_LOGIN_CAP_H
/* Insert login class environment variables. */
if (ctx->runas.class) {
login_cap_t *lc = login_getclass(ctx->runas.class);
if (lc != NULL) {
setusercontext(lc, ctx->runas.pw,
ctx->runas.pw->pw_uid, LOGIN_SETPATH|LOGIN_SETENV);
login_close(lc);
}
}
#endif /* HAVE_LOGIN_CAP_H */
#ifdef _PATH_ENVIRONMENT
/* Insert system-wide environment variables. */
if (!read_env_file(ctx, _PATH_ENVIRONMENT, true, false))
sudo_warn("%s", _PATH_ENVIRONMENT);
#endif
for (ep = env.envp; *ep; ep++)
env_update_didvar(*ep, &didvar);
}
/* Pull in vars we want to keep from the old environment. */
if (env.old_envp != NULL) {
for (ep = env.old_envp; *ep; ep++) {
bool keepit;
/*
* Look up the variable in the env_check and env_keep lists.
*/
keepit = env_should_keep(ctx, *ep);
/*
* Do SUDO_PS1 -> PS1 conversion.
* This must happen *after* env_should_keep() is called.
*/
if (strncmp(*ep, "SUDO_PS1=", 9) == 0)
ps1 = *ep + 5;
if (keepit) {
/* Preserve variable. */
CHECK_PUTENV(*ep, true, false);
env_update_didvar(*ep, &didvar);
}
}
}
didvar |= didvar << 16; /* convert DID_* to KEPT_* */
/*
* Add in defaults. In -i mode these come from the runas user,
* otherwise they may be from the user's environment (depends
* on sudoers options).
*/
if (ISSET(ctx->mode, MODE_LOGIN_SHELL)) {
CHECK_SETENV2("SHELL", ctx->runas.pw->pw_shell,
ISSET(didvar, DID_SHELL), true);
#ifdef _AIX
CHECK_SETENV2("LOGIN", ctx->runas.pw->pw_name,
ISSET(didvar, DID_LOGIN), true);
#endif
CHECK_SETENV2("LOGNAME", ctx->runas.pw->pw_name,
ISSET(didvar, DID_LOGNAME), true);
CHECK_SETENV2("USER", ctx->runas.pw->pw_name,
ISSET(didvar, DID_USER), true);
} else {
/* We will set LOGNAME later in the def_set_logname case. */
if (!def_set_logname) {
#ifdef _AIX
if (!ISSET(didvar, DID_LOGIN))
CHECK_SETENV2("LOGIN", ctx->user.name, false, true);
#endif
if (!ISSET(didvar, DID_LOGNAME))
CHECK_SETENV2("LOGNAME", ctx->user.name, false, true);
if (!ISSET(didvar, DID_USER))
CHECK_SETENV2("USER", ctx->user.name, false, true);
}
}
/* If we didn't keep HOME, reset it based on target user. */
if (!ISSET(didvar, KEPT_HOME))
reset_home = true;
/*
* Set MAIL to target user in -i mode or if MAIL is not preserved
* from user's environment.
*/
if (ISSET(ctx->mode, MODE_LOGIN_SHELL) || !ISSET(didvar, KEPT_MAIL)) {
if (_PATH_MAILDIR[sizeof(_PATH_MAILDIR) - 2] == '/') {
len = asprintf(&cp, "MAIL=%s%s", _PATH_MAILDIR,
ctx->runas.pw->pw_name);
} else {
len = asprintf(&cp, "MAIL=%s/%s", _PATH_MAILDIR,
ctx->runas.pw->pw_name);
}
if (len == -1)
goto bad;
if (sudo_putenv(cp, ISSET(didvar, DID_MAIL), true) == -1) {
free(cp);
goto bad;
}
sudoers_gc_add(GC_PTR, cp);
}
} else {
/*
* Copy environ entries as long as they don't match env_delete or
* env_check.
*/
if (env.old_envp != NULL) {
for (ep = env.old_envp; *ep; ep++) {
/* Add variable unless it matches a blocklist. */
if (!env_should_delete(*ep)) {
if (strncmp(*ep, "SUDO_PS1=", 9) == 0)
ps1 = *ep + 5;
else if (strncmp(*ep, "SHELL=", 6) == 0)
SET(didvar, DID_SHELL);
else if (strncmp(*ep, "PATH=", 5) == 0)
SET(didvar, DID_PATH);
else if (strncmp(*ep, "TERM=", 5) == 0)
SET(didvar, DID_TERM);
CHECK_PUTENV(*ep, true, false);
}
}
}
}
/* Replace the PATH envariable with a secure one? */
if (def_secure_path && !user_is_exempt(ctx)) {
CHECK_SETENV2("PATH", def_secure_path, true, true);
SET(didvar, DID_PATH);
}
/*
* Set LOGIN, LOGNAME, and USER to target if "set_logname" is not
* disabled. We skip this if we are running a login shell (because
* they have already been set).
*/
if (def_set_logname && !ISSET(ctx->mode, MODE_LOGIN_SHELL)) {
if ((didvar & KEPT_USER_VARIABLES) == 0) {
/* Nothing preserved, set them all. */
#ifdef _AIX
CHECK_SETENV2("LOGIN", ctx->runas.pw->pw_name, true, true);
#endif
CHECK_SETENV2("LOGNAME", ctx->runas.pw->pw_name, true, true);
CHECK_SETENV2("USER", ctx->runas.pw->pw_name, true, true);
} else if ((didvar & KEPT_USER_VARIABLES) != KEPT_USER_VARIABLES) {
/*
* Preserved some of LOGIN, LOGNAME, USER but not all.
* Make the unset ones match so we don't end up with some
* set to the invoking user and others set to the runas user.
*/
if (ISSET(didvar, KEPT_LOGNAME))
cp = sudo_getenv("LOGNAME");
#ifdef _AIX
else if (ISSET(didvar, KEPT_LOGIN))
cp = sudo_getenv("LOGIN");
#endif
else if (ISSET(didvar, KEPT_USER))
cp = sudo_getenv("USER");
else
cp = NULL;
if (cp != NULL) {
#ifdef _AIX
if (!ISSET(didvar, KEPT_LOGIN))
CHECK_SETENV2("LOGIN", cp, true, true);
#endif
if (!ISSET(didvar, KEPT_LOGNAME))
CHECK_SETENV2("LOGNAME", cp, true, true);
if (!ISSET(didvar, KEPT_USER))
CHECK_SETENV2("USER", cp, true, true);
}
}
}
/* Set $HOME to target user if not preserving user's value. */
if (reset_home)
CHECK_SETENV2("HOME", ctx->runas.pw->pw_dir, true, true);
/* Provide default values for $SHELL, $TERM and $PATH if not set. */
if (!ISSET(didvar, DID_SHELL))
CHECK_SETENV2("SHELL", ctx->runas.pw->pw_shell, false, false);
if (!ISSET(didvar, DID_TERM))
CHECK_PUTENV("TERM=unknown", false, false);
if (!ISSET(didvar, DID_PATH))
CHECK_SETENV2("PATH", _PATH_STDPATH, false, true);
/* Set PS1 if SUDO_PS1 is set. */
if (ps1 != NULL)
CHECK_PUTENV(ps1, true, true);
/* Add the SUDO_COMMAND envariable (cmnd + args). */
if (ctx->user.cmnd_args) {
/*
* We limit ctx->user.cmnd_args to 4096 bytes to avoid an execve(2)
* failure for very long argument vectors. The command's environment
* also counts against the ARG_MAX limit.
*/
len = asprintf(&cp, "SUDO_COMMAND=%s %.*s", ctx->user.cmnd, 4096,
ctx->user.cmnd_args);
if (len == -1)
goto bad;
if (sudo_putenv(cp, true, true) == -1) {
free(cp);
goto bad;
}
sudoers_gc_add(GC_PTR, cp);
} else {
CHECK_SETENV2("SUDO_COMMAND", ctx->user.cmnd, true, true);
}
/* Add the SUDO_{USER,UID,GID,HOME} environment variables. */
CHECK_SETENV2("SUDO_USER", ctx->user.name, true, true);
(void)snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int) ctx->user.uid);
CHECK_SETENV2("SUDO_UID", idbuf, true, true);
(void)snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int) ctx->user.gid);
CHECK_SETENV2("SUDO_GID", idbuf, true, true);
CHECK_SETENV2("SUDO_HOME", ctx->user.pw->pw_dir, true, true);
debug_return_bool(true);
bad:
sudo_warn("%s", U_("unable to rebuild the environment"));
debug_return_bool(false);
}
/*
* Insert all environment variables in envp into the private copy
* of the environment.
* Returns true on success or false on failure.
*/
bool
insert_env_vars(char * const envp[])
{
char * const *ep;
bool ret = true;
debug_decl(insert_env_vars, SUDOERS_DEBUG_ENV);
/* Add user-specified environment variables. */
if (envp != NULL) {
for (ep = envp; *ep != NULL; ep++) {
/* XXX - no undo on failure */
if (sudo_putenv(*ep, true, true) == -1) {
ret = false;
break;
}
}
}
debug_return_bool(ret);
}
/*
* Validate the list of environment variables passed in on the command
* line against env_delete, env_check, and env_keep.
* Calls log_warning() if any specified variables are not allowed.
* Returns true if allowed, else false.
*/
bool
validate_env_vars(const struct sudoers_context *ctx, char * const env_vars[])
{
char * const *ep;
char errbuf[4096];
char *errpos = errbuf;
bool okvar, ret = true;
debug_decl(validate_env_vars, SUDOERS_DEBUG_ENV);
if (env_vars == NULL)
debug_return_bool(true); /* nothing to do */
/* Add user-specified environment variables. */
for (ep = env_vars; *ep != NULL; ep++) {
char *eq = strchr(*ep, '=');
if (eq == NULL || eq == *ep) {
/* Must be in the form var=val. */
okvar = false;
} else if (def_secure_path && !user_is_exempt(ctx) &&
strncmp(*ep, "PATH=", 5) == 0) {
okvar = false;
} else if (def_env_reset) {
okvar = env_should_keep(ctx, *ep);
} else {
okvar = !env_should_delete(*ep);
}
if (okvar == false) {
/* Not allowed, append to error buffer if space remains. */
if (errpos < &errbuf[sizeof(errbuf)]) {
const size_t varlen = strcspn(*ep, "=");
const size_t errsize = sizeof(errbuf) - (size_t)(errpos - errbuf);
int len = snprintf(errpos, errsize, "%s%.*s",
errpos != errbuf ? ", " : "", (int)varlen, *ep);
if (len >= ssizeof(errbuf) - (errpos - errbuf)) {
memcpy(&errbuf[sizeof(errbuf) - 4], "...", 4);
errpos = &errbuf[sizeof(errbuf)];
} else {
errpos += len;
}
}
}
}
if (errpos != errbuf) {
/* XXX - audit? */
log_warningx(ctx, 0,
N_("sorry, you are not allowed to set the following environment variables: %s"), errbuf);
ret = false;
}
debug_return_bool(ret);
}
static void *
env_file_open_local(const char *path)
{
struct env_file_local *efl;
debug_decl(env_file_open_local, SUDOERS_DEBUG_ENV);
efl = calloc(1, sizeof(*efl));
if (efl != NULL) {
if ((efl->fp = fopen(path, "r")) == NULL) {
if (errno != ENOENT) {
free(efl);
efl = NULL;
}
}
}
debug_return_ptr(efl);
}
static void
env_file_close_local(void *cookie)
{
struct env_file_local *efl = cookie;
debug_decl(env_file_close_local, SUDOERS_DEBUG_ENV);
if (efl != NULL) {
if (efl->fp != NULL)
fclose(efl->fp);
free(efl->line);
free(efl);
}
debug_return;
}
/*
* Parse /etc/environment lines ala AIX and Linux.
* Lines may be in either of three formats:
* NAME=VALUE
* NAME="VALUE"
* NAME='VALUE'
* with an optional "export" prefix so the shell can source the file.
* Invalid lines, blank lines, or lines consisting solely of a comment
* character are skipped.
*/
static char *
env_file_next_local(void *cookie, int *errnum)
{
struct env_file_local *efl = cookie;
char *var, *val, *ret = NULL;
size_t var_len, val_len;
debug_decl(env_file_next_local, SUDOERS_DEBUG_ENV);
*errnum = 0;
if (efl->fp == NULL)
debug_return_ptr(NULL);
for (;;) {
if (sudo_parseln(&efl->line, &efl->linesize, NULL, efl->fp, PARSELN_CONT_IGN) == -1) {
if (!feof(efl->fp))
*errnum = errno;
break;
}
/* Skip blank or comment lines */
if (*(var = efl->line) == '\0')
continue;
/* Skip optional "export " */
if (strncmp(var, "export", 6) == 0 && isspace((unsigned char) var[6])) {
var += 7;
while (isspace((unsigned char) *var)) {
var++;
}
}
/* Must be of the form name=["']value['"] */
for (val = var; *val != '\0' && *val != '='; val++)
continue;
if (var == val || *val != '=')
continue;
var_len = (size_t)(val - var);
val_len = strlen(++val);
/* Strip leading and trailing single/double quotes */
if ((val[0] == '\'' || val[0] == '\"') && val_len > 1 && val[0] == val[val_len - 1]) {
val[val_len - 1] = '\0';
val++;
val_len -= 2;
}
if ((ret = malloc(var_len + 1 + val_len + 1)) == NULL) {
*errnum = errno;
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
} else {
memcpy(ret, var, var_len + 1); /* includes '=' */
memcpy(ret + var_len + 1, val, val_len + 1); /* includes NUL */
sudoers_gc_add(GC_PTR, ret);
}
break;
}
debug_return_str(ret);
}
static struct sudoers_env_file env_file_sudoers = {
env_file_open_local,
env_file_close_local,
env_file_next_local
};
static struct sudoers_env_file env_file_system = {
env_file_open_local,
env_file_close_local,
env_file_next_local
};
void
register_env_file(void * (*ef_open)(const char *), void (*ef_close)(void *),
char * (*ef_next)(void *, int *), bool sys)
{
struct sudoers_env_file *ef = sys ? &env_file_system : &env_file_sudoers;
ef->open = ef_open;
ef->close = ef_close;
ef->next = ef_next;
}
bool
read_env_file(const struct sudoers_context *ctx, const char *path,
bool overwrite, bool restricted)
{
struct sudoers_env_file *ef;
bool ret = true;
char *envstr;
void *cookie;
int errnum;
debug_decl(read_env_file, SUDOERS_DEBUG_ENV);
/*
* The environment file may be handled differently depending on
* whether it is specified in sudoers or the system.
*/
if (path == def_env_file || path == def_restricted_env_file)
ef = &env_file_sudoers;
else
ef = &env_file_system;
cookie = ef->open(path);
if (cookie == NULL)
debug_return_bool(false);
for (;;) {
/* Keep reading until EOF or error. */
if ((envstr = ef->next(cookie, &errnum)) == NULL) {
if (errnum != 0)
ret = false;
break;
}
/*
* If the env file is restricted, apply env_check and env_keep
* when env_reset is set or env_delete when it is not.
*/
if (restricted) {
if (def_env_reset ? !env_should_keep(ctx, envstr) : env_should_delete(envstr)) {
free(envstr);
continue;
}
}
if (sudo_putenv(envstr, true, overwrite) == -1) {
/* XXX - no undo on failure */
ret = false;
break;
}
}
ef->close(cookie);
debug_return_bool(ret);
}
bool
init_envtables(void)
{
struct list_member *cur;
const char **p;
debug_decl(init_envtables, SUDOERS_DEBUG_ENV);
/* Fill in the "env_delete" list. */
for (p = initial_badenv_table; *p; p++) {
cur = calloc(1, sizeof(struct list_member));
if (cur == NULL || (cur->value = strdup(*p)) == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
free(cur);
debug_return_bool(false);
}
SLIST_INSERT_HEAD(&def_env_delete, cur, entries);
}
/* Fill in the "env_check" list. */
for (p = initial_checkenv_table; *p; p++) {
cur = calloc(1, sizeof(struct list_member));
if (cur == NULL || (cur->value = strdup(*p)) == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
free(cur);
debug_return_bool(false);
}
SLIST_INSERT_HEAD(&def_env_check, cur, entries);
}
/* Fill in the "env_keep" list. */
for (p = initial_keepenv_table; *p; p++) {
cur = calloc(1, sizeof(struct list_member));
if (cur == NULL || (cur->value = strdup(*p)) == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"unable to allocate memory");
free(cur);
debug_return_bool(false);
}
SLIST_INSERT_HEAD(&def_env_keep, cur, entries);
}
debug_return_bool(true);
}
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