1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337
|
/*
* environ[] array cleanup code and getenv() wrappers
*
* No copyright is claimed. This code is in the public domain; do with
* it what you wish.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#else
#define PR_GET_DUMPABLE 3
#endif
#if (!defined(HAVE_PRCTL) && defined(linux))
#include <sys/syscall.h>
#endif
#include <unistd.h>
#include <sys/types.h>
#include "env.h"
#include "strv.h"
#include "all-io.h"
#ifndef HAVE_ENVIRON_DECL
extern char **environ;
#endif
static char * const forbid[] = {
"BASH_ENV=", /* GNU creeping featurism strikes again... */
"ENV=",
"HOME=",
"IFS=",
"KRB_CONF=",
"LD_", /* anything with the LD_ prefix */
"LIBPATH=",
"MAIL=",
"NLSPATH=",
"PATH=",
"SHELL=",
"SHLIB_PATH=",
(char *) 0
};
/* these are allowed, but with no slashes inside
(to work around security problems in GNU gettext) */
static char * const noslash[] = {
"LANG=",
"LANGUAGE=",
"LC_", /* anything with the LC_ prefix */
(char *) 0
};
struct ul_env_list {
char *name;
char *value;
struct ul_env_list *next;
};
/*
* Saves to the list and returns a pointer to the new head of the list.
*/
static struct ul_env_list *env_list_add( struct ul_env_list *ls0,
const char *name, size_t namesz,
const char *value, size_t valsz)
{
struct ul_env_list *ls;
ls = calloc(1, sizeof(struct ul_env_list) + namesz + valsz + 2);
if (!ls)
return ls0;
ls->name = ((char *) ls) + sizeof(struct ul_env_list);
ls->value = ls->name + namesz + 1;
memcpy(ls->name, name, namesz);
memcpy(ls->value, value, valsz);
ls->next = ls0;
return ls;
}
/*
* Saves the @str (with the name=value string) to the @ls and returns a pointer
* to the new head of the list.
*/
static struct ul_env_list *env_list_add_from_string(struct ul_env_list *ls,
const char *str)
{
size_t namesz = 0, valsz = 0;
const char *val;
if (!str || !*str)
return ls;
val = strchr(str, '=');
if (!val)
return NULL;
namesz = val - str;
val++;
valsz = strlen(val);
return env_list_add(ls, str, namesz, val, valsz);
}
/*
* Saves the @name and @value to @ls0 and returns a pointer to the new head of
* the list.
*/
struct ul_env_list *env_list_add_variable(
struct ul_env_list *ls,
const char *name, const char *value)
{
if (!name || !*name)
return ls;
return env_list_add(ls, name, strlen(name), value, value ? strlen(value) : 0);
}
/*
* Calls getenv() and adds the result to the list.
*/
struct ul_env_list *env_list_add_getenv(struct ul_env_list *ls,
const char *name, const char *dflt)
{
const char *val;
if (!name)
return ls;
val = getenv(name);
if (!val)
val= dflt;
if (val)
ls = env_list_add_variable(ls, name, val);
return ls;
}
/*
* Calls getenv() for each name (comma-separated) in @str and adds the results
* to the list.
*/
struct ul_env_list *env_list_add_getenvs(struct ul_env_list *ls, const char *str)
{
char **all, **name;
if (!str)
return ls;
all = strv_split(str, ",");
if (!all)
return ls;
STRV_FOREACH(name, all)
ls = env_list_add_getenv(ls, *name, NULL);
strv_free(all);
return ls;
}
/*
* Use env_list_from_fd() to read environment from @fd.
*
* @fd must be /proc/<pid>/environ file.
*/
struct ul_env_list *env_list_from_fd(int fd)
{
char *buf = NULL, *p;
ssize_t rc = 0;
struct ul_env_list *ls = NULL;
errno = 0;
if ((rc = read_all_alloc(fd, &buf)) < 1)
return NULL;
buf[rc] = '\0';
p = buf;
while (rc > 0) {
ls = env_list_add_from_string(ls, p);
p += strlen(p) + 1;
rc -= strlen(p) + 1;
}
free(buf);
return ls;
}
/*
* Use setenv() for all stuff in @ls.
*/
int env_list_setenv(struct ul_env_list *ls, int overwrite)
{
int rc = 0;
while (ls && rc == 0) {
if (ls->name && ls->value)
rc = setenv(ls->name, ls->value, overwrite);
ls = ls->next;
}
return rc;
}
void env_list_free(struct ul_env_list *ls)
{
while (ls) {
struct ul_env_list *x = ls;
ls = ls->next;
free(x);
}
}
/*
* Removes unwanted variables from environ[]. If @org is not NULL than stores
* unwnated variables to the list.
*/
void __sanitize_env(struct ul_env_list **org)
{
char **envp = environ;
char * const *bad;
char **cur;
int last = 0;
for (cur = envp; *cur; cur++)
last++;
for (cur = envp; *cur; cur++) {
for (bad = forbid; *bad; bad++) {
if (strncmp(*cur, *bad, strlen(*bad)) == 0) {
if (org)
*org = env_list_add_from_string(*org, *cur);
last = ul_remove_entry(envp, cur - envp, last);
cur--;
break;
}
}
}
for (cur = envp; *cur; cur++) {
for (bad = noslash; *bad; bad++) {
if (strncmp(*cur, *bad, strlen(*bad)) != 0)
continue;
if (!strchr(*cur, '/'))
continue; /* OK */
if (org)
*org = env_list_add_from_string(*org, *cur);
last = ul_remove_entry(envp, cur - envp, last);
cur--;
break;
}
}
}
void sanitize_env(void)
{
__sanitize_env(NULL);
}
char *safe_getenv(const char *arg)
{
if ((getuid() != geteuid()) || (getgid() != getegid()))
return NULL;
#ifdef HAVE_PRCTL
if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
return NULL;
#else
#if (defined(linux) && defined(SYS_prctl))
if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
return NULL;
#endif
#endif
#ifdef HAVE_SECURE_GETENV
return secure_getenv(arg);
#elif HAVE___SECURE_GETENV
return __secure_getenv(arg);
#else
return getenv(arg);
#endif
}
#ifdef TEST_PROGRAM
int main(void)
{
char *const *bad;
char copy[32];
char *p;
int retval = EXIT_SUCCESS;
struct ul_env_list *removed = NULL;
/* define env. */
for (bad = forbid; *bad; bad++) {
strcpy(copy, *bad);
p = strchr(copy, '=');
if (p)
*p = '\0';
setenv(copy, "abc", 1);
}
/* removed */
__sanitize_env(&removed);
/* check removal */
for (bad = forbid; *bad; bad++) {
strcpy(copy, *bad);
p = strchr(copy, '=');
if (p)
*p = '\0';
p = getenv(copy);
if (p) {
warnx("%s was not removed", copy);
retval = EXIT_FAILURE;
}
}
/* restore removed */
env_list_setenv(removed, 0);
/* check restore */
for (bad = forbid; *bad; bad++) {
strcpy(copy, *bad);
p = strchr(copy, '=');
if (p)
*p = '\0';
p = getenv(copy);
if (!p) {
warnx("%s was not restored", copy);
retval = EXIT_FAILURE;
}
}
env_list_free(removed);
return retval;
}
#endif
|