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9e26ced9809bcac96a34dc89825cdcee4e17a078
systemd/src/core/smack-setup.c
Zbigniew Jędrzejewski-Szmek 3f1812180b core/smack-setup: use RET_NERRNO and RET_GATHER
2025-05-31 16:36:43 +02:00

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
Copyright © 2013 Intel Corporation
Authors:
Nathaniel Chen <nathaniel.chen@intel.com>
***/
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include "sd-messages.h"
#include "alloc-util.h"
#include "dirent-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "log.h"
#include "smack-setup.h"
#include "string-util.h"
#if ENABLE_SMACK
static int fdopen_unlocked_at(int dfd, const char *dir, const char *name, int *status, FILE **ret_file) {
int fd, r;
FILE *f;
fd = openat(dfd, name, O_RDONLY|O_CLOEXEC);
if (fd < 0) {
if (*status == 0)
*status = -errno;
return log_warning_errno(errno, "Failed to open \"%s/%s\": %m", dir, name);
}
r = fdopen_unlocked(fd, "r", &f);
if (r < 0) {
if (*status == 0)
*status = r;
safe_close(fd);
return log_error_errno(r, "Failed to open \"%s/%s\": %m", dir, name);
}
*ret_file = f;
return 0;
}
static int write_access2_rules(const char *srcdir) {
_cleanup_close_ int load2_fd = -EBADF, change_fd = -EBADF;
_cleanup_closedir_ DIR *dir = NULL;
int dfd, r;
load2_fd = r = RET_NERRNO(open("/sys/fs/smackfs/load2", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY));
if (r < 0) {
if (r != -ENOENT)
log_warning_errno(r, "Failed to open %s: %m", "/sys/fs/smackfs/load2");
return r;
}
change_fd = r = RET_NERRNO(open("/sys/fs/smackfs/change-rule", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY));
if (r < 0) {
if (r != -ENOENT)
log_warning_errno(r, "Failed to open %s: %m", "/sys/fs/smackfs/change-rule");
return r;
}
/* write rules to load2 or change-rule from every file in the directory */
dir = opendir(srcdir);
if (!dir) {
if (errno != ENOENT)
log_warning_errno(errno, "Failed to open %s/: %m", srcdir);
return errno; /* positive on purpose */
}
dfd = dirfd(dir);
assert(dfd >= 0);
r = 0;
FOREACH_DIRENT(entry, dir, return 0) {
_cleanup_fclose_ FILE *policy = NULL;
if (!dirent_is_file(entry))
continue;
if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
continue;
/* load2 write rules in the kernel require a line buffered stream */
for (;;) {
_cleanup_free_ char *buf = NULL, *sbj = NULL, *obj = NULL, *acc1 = NULL, *acc2 = NULL;
int q;
q = read_line(policy, NAME_MAX, &buf);
if (q < 0)
return log_error_errno(q, "%s/%s: failed to read line: %m", srcdir, entry->d_name);
if (q == 0)
break;
if (isempty(buf) || strchr(COMMENTS, buf[0]))
continue;
/* if 3 args -> load rule : subject object access1 */
/* if 4 args -> change rule : subject object access1 access2 */
if (sscanf(buf, "%ms %ms %ms %ms", &sbj, &obj, &acc1, &acc2) < 3) {
log_error_errno(errno, "%s/%s: failed to parse rule '%s', ignoring.",
srcdir, entry->d_name, buf);
continue;
}
q = RET_NERRNO(write(isempty(acc2) ? load2_fd : change_fd, buf, strlen(buf)));
if (q < 0) {
log_error_errno(q, "%s/%s: failed to write '%s' to '%s': %m",
srcdir, entry->d_name,
buf, isempty(acc2) ? "/sys/fs/smackfs/load2" : "/sys/fs/smackfs/change-rule");
RET_GATHER(r, q);
}
}
}
return r;
}
static int write_cipso2_rules(const char *srcdir) {
_cleanup_close_ int cipso2_fd = -EBADF;
_cleanup_closedir_ DIR *dir = NULL;
int dfd, r;
cipso2_fd = r = RET_NERRNO(open("/sys/fs/smackfs/cipso2", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY));
if (r < 0) {
if (r != -ENOENT)
log_warning_errno(r, "Failed to open %s: %m", "/sys/fs/smackfs/cipso2");
return r;
}
/* write rules to cipso2 from every file in the directory */
dir = opendir(srcdir);
if (!dir) {
if (errno != ENOENT)
log_warning_errno(errno, "Failed to open %s/: %m", srcdir);
return errno; /* positive on purpose */
}
dfd = dirfd(dir);
assert(dfd >= 0);
r = 0;
FOREACH_DIRENT(entry, dir, return 0) {
_cleanup_fclose_ FILE *policy = NULL;
if (!dirent_is_file(entry))
continue;
if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
continue;
/* cipso2 write rules in the kernel require a line buffered stream */
for (;;) {
_cleanup_free_ char *buf = NULL;
int q;
q = read_line(policy, NAME_MAX, &buf);
if (q < 0)
return log_error_errno(q, "%s/%s: failed to read line: %m",
srcdir, entry->d_name);
if (q == 0)
break;
if (isempty(buf) || strchr(COMMENTS, buf[0]))
continue;
q = RET_NERRNO(write(cipso2_fd, buf, strlen(buf)));
if (q < 0) {
log_error_errno(q, "%s/%s: failed to write '%s' to %s: %m",
srcdir, entry->d_name,
buf, "/sys/fs/smackfs/cipso2");
RET_GATHER(r, q);
break;
}
}
}
return r;
}
static int write_netlabel_rules(const char *srcdir) {
_cleanup_fclose_ FILE *dst = NULL;
_cleanup_closedir_ DIR *dir = NULL;
int dfd, r;
dst = fopen("/sys/fs/smackfs/netlabel", "we");
if (!dst) {
if (errno != ENOENT)
log_warning_errno(errno, "Failed to open %s/: %m", "/sys/fs/smackfs/netlabel");
return -errno; /* negative error */
}
/* write rules to dst from every file in the directory */
dir = opendir(srcdir);
if (!dir) {
if (errno != ENOENT)
log_warning_errno(errno, "Failed to open %s/: %m", srcdir);
return errno; /* positive on purpose */
}
dfd = dirfd(dir);
assert(dfd >= 0);
r = 0;
FOREACH_DIRENT(entry, dir, return 0) {
_cleanup_fclose_ FILE *policy = NULL;
if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
continue;
/* load2 write rules in the kernel require a line buffered stream */
for (;;) {
_cleanup_free_ char *buf = NULL;
int q;
q = read_line(policy, NAME_MAX, &buf);
if (q < 0)
return log_error_errno(q, "%s/%s: failed to read line: %m",
srcdir, entry->d_name);
if (q == 0)
break;
if (!fputs(buf, dst)) {
log_error_errno(errno, "Failed to write line to %s: %m", "/sys/fs/smackfs/netlabel");
RET_GATHER(r, -errno);
break;
}
q = fflush_and_check(dst);
if (q < 0) {
log_error_errno(q, "Failed to flush %s: %m", "/sys/fs/smackfs/netlabel");
RET_GATHER(r, q);
break;
}
}
}
return r;
}
static int write_onlycap_list(void) {
_cleanup_close_ int onlycap_fd = -EBADF;
_cleanup_free_ char *list = NULL;
_cleanup_fclose_ FILE *f = NULL;
size_t len = 0;
int r;
f = fopen("/etc/smack/onlycap", "re");
if (!f) {
if (errno != ENOENT)
log_warning_errno(errno, "Failed to open %s: %m", "/etc/smack/onlycap");
return errno == ENOENT ? ENOENT : -errno;
}
for (;;) {
_cleanup_free_ char *buf = NULL;
size_t l;
r = read_line(f, LONG_LINE_MAX, &buf);
if (r < 0)
return log_error_errno(r, "%s: failed to read line: %m", "/etc/smack/onlycap");
if (r == 0)
break;
if (isempty(buf) || strchr(COMMENTS, *buf))
continue;
l = strlen(buf);
if (!GREEDY_REALLOC(list, len + l + 1))
return log_oom();
stpcpy(list + len, buf)[0] = ' ';
len += l + 1;
}
if (len == 0)
return 0;
list[len - 1] = 0;
onlycap_fd = r = RET_NERRNO(open("/sys/fs/smackfs/onlycap", O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY));
if (r < 0) {
if (r != -ENOENT)
log_warning_errno(r, "Failed to open %s: %m", "/sys/fs/smackfs/onlycap");
return r;
}
r = RET_NERRNO(write(onlycap_fd, list, len));
if (r < 0)
return log_error_errno(r, "%s: failed to write onlycap list(%s): %m",
"/sys/fs/smackfs/onlycap", list);
return 0;
}
#endif
int mac_smack_setup(bool *loaded_policy) {
#if ENABLE_SMACK
int r;
assert(loaded_policy);
r = write_access2_rules("/etc/smack/accesses.d");
switch (r) {
case -ENOENT:
log_debug("Smack is not enabled in the kernel.");
return 0;
case ENOENT:
log_debug("Smack access rules directory '/etc/smack/accesses.d/' not found");
return 0;
case 0:
log_info("Successfully loaded Smack policies.");
break;
default:
log_warning_errno(r, "Failed to load Smack access rules, ignoring: %m");
return 0;
}
#if HAVE_SMACK_RUN_LABEL
r = write_string_file("/proc/self/attr/current", SMACK_RUN_LABEL, WRITE_STRING_FILE_DISABLE_BUFFER);
if (r < 0)
log_warning_errno(r, "Failed to set SMACK label \"" SMACK_RUN_LABEL "\" on self: %m");
r = write_string_file("/sys/fs/smackfs/ambient", SMACK_RUN_LABEL, WRITE_STRING_FILE_DISABLE_BUFFER);
if (r < 0)
log_warning_errno(r, "Failed to set SMACK ambient label \"" SMACK_RUN_LABEL "\": %m");
r = write_string_file("/sys/fs/smackfs/netlabel",
"0.0.0.0/0 " SMACK_RUN_LABEL, WRITE_STRING_FILE_DISABLE_BUFFER);
if (r < 0)
log_warning_errno(r, "Failed to set SMACK netlabel rule \"0.0.0.0/0 " SMACK_RUN_LABEL "\": %m");
r = write_string_file("/sys/fs/smackfs/netlabel", "127.0.0.1 -CIPSO", WRITE_STRING_FILE_DISABLE_BUFFER);
if (r < 0)
log_warning_errno(r, "Failed to set SMACK netlabel rule \"127.0.0.1 -CIPSO\": %m");
#endif
r = write_cipso2_rules("/etc/smack/cipso.d");
switch (r) {
case -ENOENT:
log_debug("Smack/CIPSO is not enabled in the kernel.");
return 0;
case ENOENT:
log_debug("Smack/CIPSO access rules directory '/etc/smack/cipso.d/' not found");
break;
case 0:
log_info("Successfully loaded Smack/CIPSO policies.");
break;
default:
log_warning_errno(r, "Failed to load Smack/CIPSO access rules, ignoring: %m");
}
r = write_netlabel_rules("/etc/smack/netlabel.d");
switch (r) {
case -ENOENT:
log_debug("Smack/CIPSO is not enabled in the kernel.");
return 0;
case ENOENT:
log_debug("Smack network host rules directory '/etc/smack/netlabel.d/' not found");
break;
case 0:
log_info("Successfully loaded Smack network host rules.");
break;
default:
log_warning_errno(r, "Failed to load Smack network host rules: %m, ignoring.");
}
r = write_onlycap_list();
switch (r) {
case -ENOENT:
log_debug("Smack is not enabled in the kernel.");
break;
case ENOENT:
log_debug("Smack onlycap list file '/etc/smack/onlycap' not found");
break;
case 0:
log_info("Successfully wrote Smack onlycap list.");
break;
default:
return log_struct_errno(LOG_EMERG, r,
LOG_MESSAGE("Failed to write Smack onlycap list: %m"),
LOG_MESSAGE_ID(SD_MESSAGE_SMACK_FAILED_WRITE_STR));
}
*loaded_policy = true;
#endif
return 0;
}
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