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-rw-r--r--src/basic/smack-util.c289
1 files changed, 289 insertions, 0 deletions
diff --git a/src/basic/smack-util.c b/src/basic/smack-util.c
new file mode 100644
index 0000000..123d00e
--- /dev/null
+++ b/src/basic/smack-util.c
@@ -0,0 +1,289 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/***
+ Copyright © 2013 Intel Corporation
+
+ Author: Auke Kok <auke-jan.h.kok@intel.com>
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/xattr.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "log.h"
+#include "macro.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "smack-util.h"
+#include "stdio-util.h"
+#include "string-table.h"
+#include "xattr-util.h"
+
+#if ENABLE_SMACK
+bool mac_smack_use(void) {
+ static int cached_use = -1;
+
+ if (cached_use < 0)
+ cached_use = access("/sys/fs/smackfs/", F_OK) >= 0;
+
+ return cached_use;
+}
+
+static const char* const smack_attr_table[_SMACK_ATTR_MAX] = {
+ [SMACK_ATTR_ACCESS] = "security.SMACK64",
+ [SMACK_ATTR_EXEC] = "security.SMACK64EXEC",
+ [SMACK_ATTR_MMAP] = "security.SMACK64MMAP",
+ [SMACK_ATTR_TRANSMUTE] = "security.SMACK64TRANSMUTE",
+ [SMACK_ATTR_IPIN] = "security.SMACK64IPIN",
+ [SMACK_ATTR_IPOUT] = "security.SMACK64IPOUT",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(smack_attr, SmackAttr);
+
+int mac_smack_read(const char *path, SmackAttr attr, char **label) {
+ assert(path);
+ assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
+ assert(label);
+
+ if (!mac_smack_use())
+ return 0;
+
+ return getxattr_malloc(path, smack_attr_to_string(attr), label, true);
+}
+
+int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
+ assert(fd >= 0);
+ assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
+ assert(label);
+
+ if (!mac_smack_use())
+ return 0;
+
+ return fgetxattr_malloc(fd, smack_attr_to_string(attr), label);
+}
+
+int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
+ int r;
+
+ assert(path);
+ assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
+
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = lsetxattr(path, smack_attr_to_string(attr), label, strlen(label), 0);
+ else
+ r = lremovexattr(path, smack_attr_to_string(attr));
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
+ int r;
+
+ assert(fd >= 0);
+ assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
+
+ if (!mac_smack_use())
+ return 0;
+
+ if (label)
+ r = fsetxattr(fd, smack_attr_to_string(attr), label, strlen(label), 0);
+ else
+ r = fremovexattr(fd, smack_attr_to_string(attr));
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+int mac_smack_apply_pid(pid_t pid, const char *label) {
+ const char *p;
+ int r = 0;
+
+ assert(label);
+
+ if (!mac_smack_use())
+ return 0;
+
+ p = procfs_file_alloca(pid, "attr/current");
+ r = write_string_file(p, label, WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return r;
+
+ return r;
+}
+
+static int smack_fix_fd(int fd , const char *abspath, LabelFixFlags flags) {
+ char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
+ const char *label;
+ struct stat st;
+ int r;
+
+ /* The caller should have done the sanity checks. */
+ assert(abspath);
+ assert(path_is_absolute(abspath));
+
+ /* Path must be in /dev. */
+ if (!path_startswith(abspath, "/dev"))
+ return 0;
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ /*
+ * Label directories and character devices "*".
+ * Label symlinks "_".
+ * Don't change anything else.
+ */
+
+ if (S_ISDIR(st.st_mode))
+ label = SMACK_STAR_LABEL;
+ else if (S_ISLNK(st.st_mode))
+ label = SMACK_FLOOR_LABEL;
+ else if (S_ISCHR(st.st_mode))
+ label = SMACK_STAR_LABEL;
+ else
+ return 0;
+
+ xsprintf(procfs_path, "/proc/self/fd/%i", fd);
+ if (setxattr(procfs_path, "security.SMACK64", label, strlen(label), 0) < 0) {
+ _cleanup_free_ char *old_label = NULL;
+
+ r = -errno;
+
+ /* If the FS doesn't support labels, then exit without warning */
+ if (r == -EOPNOTSUPP)
+ return 0;
+
+ /* It the FS is read-only and we were told to ignore failures caused by that, suppress error */
+ if (r == -EROFS && (flags & LABEL_IGNORE_EROFS))
+ return 0;
+
+ /* If the old label is identical to the new one, suppress any kind of error */
+ if (getxattr_malloc(procfs_path, "security.SMACK64", &old_label, false) >= 0 &&
+ streq(old_label, label))
+ return 0;
+
+ return log_debug_errno(r, "Unable to fix SMACK label of %s: %m", abspath);
+ }
+
+ return 0;
+}
+
+int mac_smack_fix_at(int dirfd, const char *path, LabelFixFlags flags) {
+ _cleanup_free_ char *p = NULL;
+ _cleanup_close_ int fd = -1;
+ int r;
+
+ assert(path);
+
+ if (!mac_smack_use())
+ return 0;
+
+ fd = openat(dirfd, path, O_NOFOLLOW|O_CLOEXEC|O_PATH);
+ if (fd < 0) {
+ if ((flags & LABEL_IGNORE_ENOENT) && errno == ENOENT)
+ return 0;
+
+ return -errno;
+ }
+
+ if (!path_is_absolute(path)) {
+ r = fd_get_path(fd, &p);
+ if (r < 0)
+ return r;
+ path = p;
+ }
+
+ return smack_fix_fd(fd, path, flags);
+}
+
+int mac_smack_fix(const char *path, LabelFixFlags flags) {
+ _cleanup_free_ char *abspath = NULL;
+ _cleanup_close_ int fd = -1;
+ int r;
+
+ assert(path);
+
+ if (!mac_smack_use())
+ return 0;
+
+ r = path_make_absolute_cwd(path, &abspath);
+ if (r < 0)
+ return r;
+
+ fd = open(abspath, O_NOFOLLOW|O_CLOEXEC|O_PATH);
+ if (fd < 0) {
+ if ((flags & LABEL_IGNORE_ENOENT) && errno == ENOENT)
+ return 0;
+
+ return -errno;
+ }
+
+ return smack_fix_fd(fd, abspath, flags);
+}
+
+int mac_smack_copy(const char *dest, const char *src) {
+ int r = 0;
+ _cleanup_free_ char *label = NULL;
+
+ assert(dest);
+ assert(src);
+
+ r = mac_smack_read(src, SMACK_ATTR_ACCESS, &label);
+ if (r < 0)
+ return r;
+
+ r = mac_smack_apply(dest, SMACK_ATTR_ACCESS, label);
+ if (r < 0)
+ return r;
+
+ return r;
+}
+
+#else
+bool mac_smack_use(void) {
+ return false;
+}
+
+int mac_smack_read(const char *path, SmackAttr attr, char **label) {
+ return -EOPNOTSUPP;
+}
+
+int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
+ return -EOPNOTSUPP;
+}
+
+int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
+ return 0;
+}
+
+int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
+ return 0;
+}
+
+int mac_smack_apply_pid(pid_t pid, const char *label) {
+ return 0;
+}
+
+int mac_smack_fix(const char *path, LabelFixFlags flags) {
+ return 0;
+}
+
+int mac_smack_fix_at(int dirfd, const char *path, LabelFixFlags flags) {
+ return 0;
+}
+
+int mac_smack_copy(const char *dest, const char *src) {
+ return 0;
+}
+#endif
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