#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include "selinux_internal.h"
#include "label_internal.h"
#include "callbacks.h"
#include <limits.h>
static int (*myinvalidcon) (const char *p, unsigned l, char *c) = NULL;
static int (*mycanoncon) (const char *p, unsigned l, char **c) = NULL;
static void
#ifdef __GNUC__
__attribute__ ((format(printf, 1, 2)))
#endif
default_printf(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
void
#ifdef __GNUC__
__attribute__ ((format(printf, 1, 2)))
#endif
(*myprintf) (const char *fmt,...) = &default_printf;
int myprintf_compat = 0;
void set_matchpathcon_printf(void (*f) (const char *fmt, ...))
{
myprintf = f ? f : &default_printf;
myprintf_compat = 1;
}
int compat_validate(struct selabel_handle *rec,
struct selabel_lookup_rec *contexts,
const char *path, unsigned lineno)
{
int rc;
char **ctx = &contexts->ctx_raw;
if (myinvalidcon)
rc = myinvalidcon(path, lineno, *ctx);
else if (mycanoncon)
rc = mycanoncon(path, lineno, ctx);
else {
rc = selabel_validate(rec, contexts);
if (rc < 0) {
if (lineno) {
COMPAT_LOG(SELINUX_WARNING,
"%s: line %u has invalid context %s\n",
path, lineno, *ctx);
} else {
COMPAT_LOG(SELINUX_WARNING,
"%s: has invalid context %s\n", path, *ctx);
}
}
}
return rc ? -1 : 0;
}
#ifndef BUILD_HOST
static __thread struct selabel_handle *hnd;
/*
* An array for mapping integers to contexts
*/
static __thread char **con_array;
static __thread int con_array_size;
static __thread int con_array_used;
static pthread_once_t once = PTHREAD_ONCE_INIT;
static pthread_key_t destructor_key;
static int destructor_key_initialized = 0;
static int add_array_elt(char *con)
{
if (con_array_size) {
while (con_array_used >= con_array_size) {
con_array_size *= 2;
con_array = (char **)realloc(con_array, sizeof(char*) *
con_array_size);
if (!con_array) {
con_array_size = con_array_used = 0;
return -1;
}
}
} else {
con_array_size = 1000;
con_array = (char **)malloc(sizeof(char*) * con_array_size);
if (!con_array) {
con_array_size = con_array_used = 0;
return -1;
}
}
con_array[con_array_used] = strdup(con);
if (!con_array[con_array_used])
return -1;
return con_array_used++;
}
static void free_array_elts(void)
{
con_array_size = con_array_used = 0;
free(con_array);
con_array = NULL;
}
void set_matchpathcon_invalidcon(int (*f) (const char *p, unsigned l, char *c))
{
myinvalidcon = f;
}
static int default_canoncon(const char *path, unsigned lineno, char **context)
{
char *tmpcon;
if (security_canonicalize_context_raw(*context, &tmpcon) < 0) {
if (errno == ENOENT)
return 0;
if (lineno)
myprintf("%s: line %u has invalid context %s\n", path,
lineno, *context);
else
myprintf("%s: invalid context %s\n", path, *context);
return 1;
}
free(*context);
*context = tmpcon;
return 0;
}
void set_matchpathcon_canoncon(int (*f) (const char *p, unsigned l, char **c))
{
if (f)
mycanoncon = f;
else
mycanoncon = &default_canoncon;
}
static __thread struct selinux_opt options[SELABEL_NOPT];
static __thread int notrans;
void set_matchpathcon_flags(unsigned int flags)
{
int i;
memset(options, 0, sizeof(options));
i = SELABEL_OPT_BASEONLY;
options[i].type = i;
options[i].value = (flags & MATCHPATHCON_BASEONLY) ? (char*)1 : NULL;
i = SELABEL_OPT_VALIDATE;
options[i].type = i;
options[i].value = (flags & MATCHPATHCON_VALIDATE) ? (char*)1 : NULL;
notrans = flags & MATCHPATHCON_NOTRANS;
}
/*
* An association between an inode and a
* specification.
*/
typedef struct file_spec {
ino_t ino; /* inode number */
int specind; /* index of specification in spec */
char *file; /* full pathname for diagnostic messages about conflicts */
struct file_spec *next; /* next association in hash bucket chain */
} file_spec_t;
/*
* The hash table of associations, hashed by inode number.
* Chaining is used for collisions, with elements ordered
* by inode number in each bucket. Each hash bucket has a dummy
* header.
*/
#define HASH_BITS 16
#define HASH_BUCKETS (1 << HASH_BITS)
#define HASH_MASK (HASH_BUCKETS-1)
static file_spec_t *fl_head;
/*
* Try to add an association between an inode and
* a specification. If there is already an association
* for the inode and it conflicts with this specification,
* then use the specification that occurs later in the
* specification array.
*/
int matchpathcon_filespec_add(ino_t ino, int specind, const char *file)
{
file_spec_t *prevfl, *fl;
int h, ret;
struct stat sb;
if (!fl_head) {
fl_head = malloc(sizeof(file_spec_t) * HASH_BUCKETS);
if (!fl_head)
goto oom;
memset(fl_head, 0, sizeof(file_spec_t) * HASH_BUCKETS);
}
h = (ino + (ino >> HASH_BITS)) & HASH_MASK;
for (prevfl = &fl_head[h], fl = fl_head[h].next; fl;
prevfl = fl, fl = fl->next) {
if (ino == fl->ino) {
ret = lstat(fl->file, &sb);
if (ret < 0 || sb.st_ino != ino) {
fl->specind = specind;
free(fl->file);
fl->file = malloc(strlen(file) + 1);
if (!fl->file)
goto oom;
strcpy(fl->file, file);
return fl->specind;
}
if (!strcmp(con_array[fl->specind],
con_array[specind]))
return fl->specind;
myprintf
("%s: conflicting specifications for %s and %s, using %s.\n",
__FUNCTION__, file, fl->file,
con_array[fl->specind]);
free(fl->file);
fl->file = malloc(strlen(file) + 1);
if (!fl->file)
goto oom;
strcpy(fl->file, file);
return fl->specind;
}
if (ino > fl->ino)
break;
}
fl = malloc(sizeof(file_spec_t));
if (!fl)
goto oom;
fl->ino = ino;
fl->specind = specind;
fl->file = malloc(strlen(file) + 1);
if (!fl->file)
goto oom_freefl;
strcpy(fl->file, file);
fl->next = prevfl->next;
prevfl->next = fl;
return fl->specind;
oom_freefl:
free(fl);
oom:
myprintf("%s: insufficient memory for file label entry for %s\n",
__FUNCTION__, file);
return -1;
}
/*
* Evaluate the association hash table distribution.
*/
void matchpathcon_filespec_eval(void)
{
file_spec_t *fl;
int h, used, nel, len, longest;
if (!fl_head)
return;
used = 0;
longest = 0;
nel = 0;
for (h = 0; h < HASH_BUCKETS; h++) {
len = 0;
for (fl = fl_head[h].next; fl; fl = fl->next) {
len++;
}
if (len)
used++;
if (len > longest)
longest = len;
nel += len;
}
myprintf
("%s: hash table stats: %d elements, %d/%d buckets used, longest chain length %d\n",
__FUNCTION__, nel, used, HASH_BUCKETS, longest);
}
/*
* Destroy the association hash table.
*/
void matchpathcon_filespec_destroy(void)
{
file_spec_t *fl, *tmp;
int h;
free_array_elts();
if (!fl_head)
return;
for (h = 0; h < HASH_BUCKETS; h++) {
fl = fl_head[h].next;
while (fl) {
tmp = fl;
fl = fl->next;
free(tmp->file);
free(tmp);
}
fl_head[h].next = NULL;
}
free(fl_head);
fl_head = NULL;
}
static void matchpathcon_thread_destructor(void __attribute__((unused)) *ptr)
{
matchpathcon_fini();
}
void __attribute__((destructor)) matchpathcon_lib_destructor(void);
void hidden __attribute__((destructor)) matchpathcon_lib_destructor(void)
{
if (destructor_key_initialized)
__selinux_key_delete(destructor_key);
}
static void matchpathcon_init_once(void)
{
if (__selinux_key_create(&destructor_key, matchpathcon_thread_destructor) == 0)
destructor_key_initialized = 1;
}
int matchpathcon_init_prefix(const char *path, const char *subset)
{
if (!mycanoncon)
mycanoncon = default_canoncon;
__selinux_once(once, matchpathcon_init_once);
__selinux_setspecific(destructor_key, (void *)1);
options[SELABEL_OPT_SUBSET].type = SELABEL_OPT_SUBSET;
options[SELABEL_OPT_SUBSET].value = subset;
options[SELABEL_OPT_PATH].type = SELABEL_OPT_PATH;
options[SELABEL_OPT_PATH].value = path;
hnd = selabel_open(SELABEL_CTX_FILE, options, SELABEL_NOPT);
return hnd ? 0 : -1;
}
hidden_def(matchpathcon_init_prefix)
int matchpathcon_init(const char *path)
{
return matchpathcon_init_prefix(path, NULL);
}
void matchpathcon_fini(void)
{
free_array_elts();
if (hnd) {
selabel_close(hnd);
hnd = NULL;
}
}
/*
* We do not want to resolve a symlink to a real path if it is the final
* component of the name. Thus we split the pathname on the last "/" and
* determine a real path component of the first portion. We then have to
* copy the last part back on to get the final real path. Wheww.
*/
int realpath_not_final(const char *name, char *resolved_path)
{
char *last_component;
char *tmp_path, *p;
size_t len = 0;
int rc = 0;
tmp_path = strdup(name);
if (!tmp_path) {
myprintf("symlink_realpath(%s) strdup() failed: %s\n",
name, strerror(errno));
rc = -1;
goto out;
}
last_component = strrchr(tmp_path, '/');
if (last_component == tmp_path) {
last_component++;
p = strcpy(resolved_path, "");
} else if (last_component) {
*last_component = '\0';
last_component++;
p = realpath(tmp_path, resolved_path);
} else {
last_component = tmp_path;
p = realpath("./", resolved_path);
}
if (!p) {
myprintf("symlink_realpath(%s) realpath() failed: %s\n",
name, strerror(errno));
rc = -1;
goto out;
}
len = strlen(p);
if (len + strlen(last_component) + 2 > PATH_MAX) {
myprintf("symlink_realpath(%s) failed: Filename too long \n",
name);
errno=ENAMETOOLONG;
rc = -1;
goto out;
}
resolved_path += len;
strcpy(resolved_path, "/");
resolved_path += 1;
strcpy(resolved_path, last_component);
out:
free(tmp_path);
return rc;
}
int matchpathcon(const char *path, mode_t mode, char ** con)
{
char stackpath[PATH_MAX + 1];
char *p = NULL;
if (!hnd && (matchpathcon_init_prefix(NULL, NULL) < 0))
return -1;
if (S_ISLNK(mode)) {
if (!realpath_not_final(path, stackpath))
path = stackpath;
} else {
p = realpath(path, stackpath);
if (p)
path = p;
}
return notrans ?
selabel_lookup_raw(hnd, con, path, mode) :
selabel_lookup(hnd, con, path, mode);
}
int matchpathcon_index(const char *name, mode_t mode, char ** con)
{
int i = matchpathcon(name, mode, con);
if (i < 0)
return -1;
return add_array_elt(*con);
}
void matchpathcon_checkmatches(char *str __attribute__((unused)))
{
selabel_stats(hnd);
}
/* Compare two contexts to see if their differences are "significant",
* or whether the only difference is in the user. */
int selinux_file_context_cmp(const char * a,
const char * b)
{
char *rest_a, *rest_b; /* Rest of the context after the user */
if (!a && !b)
return 0;
if (!a)
return -1;
if (!b)
return 1;
rest_a = strchr((char *)a, ':');
rest_b = strchr((char *)b, ':');
if (!rest_a && !rest_b)
return 0;
if (!rest_a)
return -1;
if (!rest_b)
return 1;
return strcmp(rest_a, rest_b);
}
int selinux_file_context_verify(const char *path, mode_t mode)
{
char * con = NULL;
char * fcontext = NULL;
int rc = 0;
char stackpath[PATH_MAX + 1];
char *p = NULL;
if (S_ISLNK(mode)) {
if (!realpath_not_final(path, stackpath))
path = stackpath;
} else {
p = realpath(path, stackpath);
if (p)
path = p;
}
rc = lgetfilecon_raw(path, &con);
if (rc == -1) {
if (errno != ENOTSUP)
return -1;
else
return 0;
}
if (!hnd && (matchpathcon_init_prefix(NULL, NULL) < 0))
return -1;
if (selabel_lookup_raw(hnd, &fcontext, path, mode) != 0) {
if (errno != ENOENT)
rc = -1;
else
rc = 0;
} else {
/*
* Need to set errno to 0 as it can be set to ENOENT if the
* file_contexts.subs file does not exist (see selabel_open in
* label.c), thus causing confusion if errno is checked on return.
*/
errno = 0;
rc = (selinux_file_context_cmp(fcontext, con) == 0);
}
freecon(con);
freecon(fcontext);
return rc;
}
int selinux_lsetfilecon_default(const char *path)
{
struct stat st;
int rc = -1;
char * scontext = NULL;
if (lstat(path, &st) != 0)
return rc;
if (!hnd && (matchpathcon_init_prefix(NULL, NULL) < 0))
return -1;
/* If there's an error determining the context, or it has none,
return to allow default context */
if (selabel_lookup_raw(hnd, &scontext, path, st.st_mode)) {
if (errno == ENOENT)
rc = 0;
} else {
rc = lsetfilecon_raw(path, scontext);
freecon(scontext);
}
return rc;
}
#endif