selinux/policycoreutils/setfiles/restore.c

614 lines
13 KiB
C

#include "restore.h"
#define SKIP -2
#define ERR -1
#define MAX_EXCLUDES 1000
/*
* 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)
/*
* An association between an inode and a context.
*/
typedef struct file_spec {
ino_t ino; /* inode number */
char *con; /* matched context */
char *file; /* full pathname */
struct file_spec *next; /* next association in hash bucket chain */
} file_spec_t;
struct edir {
char *directory;
size_t size;
};
static file_spec_t *fl_head;
static int exclude(const char *file);
static int filespec_add(ino_t ino, const security_context_t con, const char *file);
static int only_changed_user(const char *a, const char *b);
struct restore_opts *r_opts = NULL;
static void filespec_destroy(void);
static void filespec_eval(void);
static int excludeCtr = 0;
static struct edir excludeArray[MAX_EXCLUDES];
void remove_exclude(const char *directory)
{
int i = 0;
for (i = 0; i < excludeCtr; i++) {
if (strcmp(directory, excludeArray[i].directory) == 0) {
free(excludeArray[i].directory);
if (i != excludeCtr-1)
excludeArray[i] = excludeArray[excludeCtr-1];
excludeCtr--;
return;
}
}
return;
}
void restore_init(struct restore_opts *opts)
{
r_opts = opts;
struct selinux_opt selinux_opts[] = {
{ SELABEL_OPT_VALIDATE, r_opts->selabel_opt_validate },
{ SELABEL_OPT_PATH, r_opts->selabel_opt_path }
};
r_opts->hnd = selabel_open(SELABEL_CTX_FILE, selinux_opts, 2);
if (!r_opts->hnd) {
perror(r_opts->selabel_opt_path);
exit(1);
}
}
void restore_finish()
{
int i;
for (i = 0; i < excludeCtr; i++) {
free(excludeArray[i].directory);
}
}
static int match(const char *name, struct stat *sb, char **con)
{
if (!(r_opts->hard_links) && !S_ISDIR(sb->st_mode) && (sb->st_nlink > 1)) {
fprintf(stderr, "Warning! %s refers to a file with more than one hard link, not fixing hard links.\n",
name);
return -1;
}
if (NULL != r_opts->rootpath) {
if (0 != strncmp(r_opts->rootpath, name, r_opts->rootpathlen)) {
fprintf(stderr, "%s: %s is not located in %s\n",
r_opts->progname, name, r_opts->rootpath);
return -1;
}
name += r_opts->rootpathlen;
}
if (r_opts->rootpath != NULL && name[0] == '\0')
/* this is actually the root dir of the alt root */
return selabel_lookup_raw(r_opts->hnd, con, "/", sb->st_mode);
else
return selabel_lookup_raw(r_opts->hnd, con, name, sb->st_mode);
}
static int restore(FTSENT *ftsent)
{
char *my_file = strdupa(ftsent->fts_path);
int ret;
char *context, *newcon;
int user_only_changed = 0;
if (match(my_file, ftsent->fts_statp, &newcon) < 0)
/* Check for no matching specification. */
return (errno == ENOENT) ? 0 : -1;
if (r_opts->progress) {
r_opts->count++;
if (r_opts->count % (80 * STAR_COUNT) == 0) {
fprintf(stdout, "\n");
fflush(stdout);
}
if (r_opts->count % STAR_COUNT == 0) {
fprintf(stdout, "*");
fflush(stdout);
}
}
/*
* Try to add an association between this inode and
* this specification. If there is already an association
* for this inode and it conflicts with this specification,
* then use the last matching specification.
*/
if (r_opts->add_assoc) {
ret = filespec_add(ftsent->fts_statp->st_ino, newcon, my_file);
if (ret < 0)
goto err;
if (ret > 0)
/* There was already an association and it took precedence. */
goto out;
}
if (r_opts->debug) {
printf("%s: %s matched by %s\n", r_opts->progname, my_file, newcon);
}
/* Get the current context of the file. */
ret = lgetfilecon_raw(ftsent->fts_accpath, &context);
if (ret < 0) {
if (errno == ENODATA) {
context = NULL;
} else {
fprintf(stderr, "%s get context on %s failed: '%s'\n",
r_opts->progname, my_file, strerror(errno));
goto err;
}
user_only_changed = 0;
} else
user_only_changed = only_changed_user(context, newcon);
/* lgetfilecon returns number of characters and ret needs to be reset
* to 0.
*/
ret = 0;
/*
* Do not relabel the file if the matching specification is
* <<none>> or the file is already labeled according to the
* specification.
*/
if ((strcmp(newcon, "<<none>>") == 0) ||
(context && (strcmp(context, newcon) == 0))) {
freecon(context);
goto out;
}
if (!r_opts->force && context && (is_context_customizable(context) > 0)) {
if (r_opts->verbose > 1) {
fprintf(stderr,
"%s: %s not reset customized by admin to %s\n",
r_opts->progname, my_file, context);
}
freecon(context);
goto out;
}
if (r_opts->verbose) {
/* If we're just doing "-v", trim out any relabels where
* the user has r_opts->changed but the role and type are the
* same. For "-vv", emit everything. */
if (r_opts->verbose > 1 || !user_only_changed) {
printf("%s reset %s context %s->%s\n",
r_opts->progname, my_file, context ?: "", newcon);
}
}
if (r_opts->logging && !user_only_changed) {
if (context)
syslog(LOG_INFO, "relabeling %s from %s to %s\n",
my_file, context, newcon);
else
syslog(LOG_INFO, "labeling %s to %s\n",
my_file, newcon);
}
if (r_opts->outfile && !user_only_changed)
fprintf(r_opts->outfile, "%s\n", my_file);
if (context)
freecon(context);
/*
* Do not relabel the file if -n was used.
*/
if (!r_opts->change || user_only_changed)
goto out;
/*
* Relabel the file to the specified context.
*/
ret = lsetfilecon(ftsent->fts_accpath, newcon);
if (ret) {
fprintf(stderr, "%s set context %s->%s failed:'%s'\n",
r_opts->progname, my_file, newcon, strerror(errno));
goto skip;
}
ret = 1;
out:
freecon(newcon);
return ret;
skip:
freecon(newcon);
return SKIP;
err:
freecon(newcon);
return ERR;
}
/*
* Apply the last matching specification to a file.
* This function is called by fts on each file during
* the directory traversal.
*/
static int apply_spec(FTSENT *ftsent)
{
if (ftsent->fts_info == FTS_DNR) {
fprintf(stderr, "%s: unable to read directory %s\n",
r_opts->progname, ftsent->fts_path);
return SKIP;
}
int rc = restore(ftsent);
if (rc == ERR) {
if (!r_opts->abort_on_error)
return SKIP;
}
return rc;
}
static int symlink_realpath(char *name, char *path)
{
char *p = NULL, *file_sep;
char *tmp_path = strdupa(name);
size_t len = 0;
if (!tmp_path) {
fprintf(stderr, "strdupa on %s failed: %s\n", name,
strerror(errno));
return -1;
}
file_sep = strrchr(tmp_path, '/');
if (file_sep == tmp_path) {
file_sep++;
p = strcpy(path, "");
} else if (file_sep) {
*file_sep = 0;
file_sep++;
p = realpath(tmp_path, path);
} else {
file_sep = tmp_path;
p = realpath("./", path);
}
if (p)
len = strlen(p);
if (!p || len + strlen(file_sep) + 2 > PATH_MAX) {
fprintf(stderr, "symlink_realpath(%s) failed %s\n", name,
strerror(errno));
return -1;
}
p += len;
/* ensure trailing slash of directory name */
if (len == 0 || *(p - 1) != '/') {
*p = '/';
p++;
}
strcpy(p, file_sep);
return 0;
}
static int process_one(char *name, int recurse_this_path)
{
int rc = 0;
const char *namelist[2] = {name, NULL};
dev_t dev_num = 0;
FTS *fts_handle = NULL;
FTSENT *ftsent = NULL;
if (r_opts == NULL){
fprintf(stderr,
"Must call initialize first!");
goto err;
}
fts_handle = fts_open((char **)namelist, r_opts->fts_flags, NULL);
if (fts_handle == NULL) {
fprintf(stderr,
"%s: error while labeling %s: %s\n",
r_opts->progname, namelist[0], strerror(errno));
goto err;
}
ftsent = fts_read(fts_handle);
if (ftsent != NULL) {
/* Keep the inode of the first one. */
dev_num = ftsent->fts_statp->st_dev;
}
do {
rc = 0;
/* Skip the post order nodes. */
if (ftsent->fts_info == FTS_DP)
continue;
/* If the XDEV flag is set and the device is different */
if (ftsent->fts_statp->st_dev != dev_num &&
FTS_XDEV == (r_opts->fts_flags & FTS_XDEV))
continue;
if (excludeCtr > 0) {
if (exclude(ftsent->fts_path)) {
fts_set(fts_handle, ftsent, FTS_SKIP);
continue;
}
}
rc = apply_spec(ftsent);
if (rc == SKIP)
fts_set(fts_handle, ftsent, FTS_SKIP);
if (rc == ERR)
goto err;
if (!recurse_this_path)
break;
} while ((ftsent = fts_read(fts_handle)) != NULL);
out:
if (r_opts->add_assoc) {
if (!r_opts->quiet)
filespec_eval();
filespec_destroy();
}
if (fts_handle)
fts_close(fts_handle);
return rc;
err:
rc = -1;
goto out;
}
int process_one_realpath(char *name, int recurse)
{
int rc = 0;
char *p;
struct stat sb;
if (r_opts == NULL){
fprintf(stderr,
"Must call initialize first!");
return -1;
}
if (!r_opts->expand_realpath) {
return process_one(name, recurse);
} else {
rc = lstat(name, &sb);
if (rc < 0) {
if (r_opts->ignore_enoent && errno == ENOENT)
return 0;
fprintf(stderr, "%s: lstat(%s) failed: %s\n",
r_opts->progname, name, strerror(errno));
return -1;
}
if (S_ISLNK(sb.st_mode)) {
char path[PATH_MAX + 1];
rc = symlink_realpath(name, path);
if (rc < 0)
return rc;
rc = process_one(path, 0);
if (rc < 0)
return rc;
p = realpath(name, NULL);
if (p) {
rc = process_one(p, recurse);
free(p);
}
return rc;
} else {
p = realpath(name, NULL);
if (!p) {
fprintf(stderr, "realpath(%s) failed %s\n", name,
strerror(errno));
return -1;
}
rc = process_one(p, recurse);
free(p);
return rc;
}
}
}
static int exclude(const char *file)
{
int i = 0;
for (i = 0; i < excludeCtr; i++) {
if (strncmp
(file, excludeArray[i].directory,
excludeArray[i].size) == 0) {
if (file[excludeArray[i].size] == 0
|| file[excludeArray[i].size] == '/') {
return 1;
}
}
}
return 0;
}
int add_exclude(const char *directory)
{
size_t len = 0;
if (directory == NULL || directory[0] != '/') {
fprintf(stderr, "Full path required for exclude: %s.\n",
directory);
return 1;
}
if (excludeCtr == MAX_EXCLUDES) {
fprintf(stderr, "Maximum excludes %d exceeded.\n",
MAX_EXCLUDES);
return 1;
}
len = strlen(directory);
while (len > 1 && directory[len - 1] == '/') {
len--;
}
excludeArray[excludeCtr].directory = strndup(directory, len);
if (excludeArray[excludeCtr].directory == NULL) {
fprintf(stderr, "Out of memory.\n");
return 1;
}
excludeArray[excludeCtr++].size = len;
return 0;
}
/* Compare two contexts to see if their differences are "significant",
* or whether the only difference is in the user. */
static int only_changed_user(const char *a, const char *b)
{
char *rest_a, *rest_b; /* Rest of the context after the user */
if (r_opts->force)
return 0;
if (!a || !b)
return 0;
rest_a = strchr(a, ':');
rest_b = strchr(b, ':');
if (!rest_a || !rest_b)
return 0;
return (strcmp(rest_a, rest_b) == 0);
}
/*
* Evaluate the association hash table distribution.
*/
static void 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;
}
if (r_opts->verbose > 1)
printf
("%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.
*/
static void filespec_destroy(void)
{
file_spec_t *fl, *tmp;
int h;
if (!fl_head)
return;
for (h = 0; h < HASH_BUCKETS; h++) {
fl = fl_head[h].next;
while (fl) {
tmp = fl;
fl = fl->next;
freecon(tmp->con);
free(tmp->file);
free(tmp);
}
fl_head[h].next = NULL;
}
free(fl_head);
fl_head = NULL;
}
/*
* Try to add an association between an inode and a context.
* If there is a different context that matched the inode,
* then use the first context that matched.
*/
static int filespec_add(ino_t ino, const security_context_t con, 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) {
freecon(fl->con);
free(fl->file);
fl->file = strdup(file);
if (!fl->file)
goto oom;
fl->con = strdup(con);
if (!fl->con)
goto oom;
return 1;
}
if (strcmp(fl->con, con) == 0)
return 1;
fprintf(stderr,
"%s: conflicting specifications for %s and %s, using %s.\n",
__FUNCTION__, file, fl->file, fl->con);
free(fl->file);
fl->file = strdup(file);
if (!fl->file)
goto oom;
return 1;
}
if (ino > fl->ino)
break;
}
fl = malloc(sizeof(file_spec_t));
if (!fl)
goto oom;
fl->ino = ino;
fl->con = strdup(con);
if (!fl->con)
goto oom_freefl;
fl->file = strdup(file);
if (!fl->file)
goto oom_freefl;
fl->next = prevfl->next;
prevfl->next = fl;
return 0;
oom_freefl:
free(fl);
oom:
fprintf(stderr,
"%s: insufficient memory for file label entry for %s\n",
__FUNCTION__, file);
return -1;
}