Simon de Vlieger
f2b82e5c20
When operating on an alternate root (--root/--image), SELinux labels must come from that root's policy, not the host's. This requires opening a separate selabel_handle against the target's policy database and remembering the root path for prefix stripping. Introduce LabelContext to carry both, and mac_label_context_new() to set it up: it reads the target's SELinux config, validates SELINUXTYPE to prevent path traversal, sets the policy root, and opens a label database scoped to the target image. Signed-off-by: Simon de Vlieger <cmdr@supakeen.com>
138 lines
3.6 KiB
C
138 lines
3.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <sys/stat.h>
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#include <unistd.h>
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#include "btrfs-util.h"
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#include "errno-util.h"
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#include "label-util.h"
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#include "path-util.h"
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#include "selinux-util.h"
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#include "smack-util.h"
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int label_fix_full(
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int atfd,
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const char *inode_path, /* path of inode to apply label to */
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const char *label_path, /* path to use as database lookup key in label database (typically same as inode_path, but not always) */
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LabelFixFlags flags,
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LabelContext *label_context) {
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int r, q;
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if (atfd < 0 && atfd != AT_FDCWD)
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return -EBADF;
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if (!inode_path && atfd < 0) /* We need at least one of atfd and an inode path */
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return -EINVAL;
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/* If both atfd and inode_path are specified, we take the specified path relative to atfd which must be an fd to a dir.
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*
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* If only atfd is specified (and inode_path is NULL), we'll operated on the inode the atfd refers to.
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*
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* If atfd is AT_FDCWD then we'll operate on the inode the path refers to.
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*/
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r = mac_selinux_fix_full(atfd, inode_path, label_path, flags, label_context);
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q = mac_smack_fix_full(atfd, inode_path, label_path, flags);
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if (r < 0)
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return r;
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if (q < 0)
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return q;
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return 0;
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}
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int symlink_label(const char *old_path, const char *new_path, LabelContext *label_context) {
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int r;
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assert(old_path);
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assert(new_path);
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r = mac_selinux_create_file_prepare(new_path, S_IFLNK, label_context);
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if (r < 0)
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return r;
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r = RET_NERRNO(symlink(old_path, new_path));
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mac_selinux_create_file_clear();
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if (r < 0)
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return r;
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return mac_smack_fix(new_path, 0);
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}
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int mknodat_label(int dirfd, const char *pathname, mode_t mode, dev_t dev, LabelContext *label_context) {
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int r;
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assert(dirfd >= 0 || dirfd == AT_FDCWD);
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assert(pathname);
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r = mac_selinux_create_file_prepare_at(dirfd, pathname, mode, label_context);
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if (r < 0)
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return r;
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r = RET_NERRNO(mknodat(dirfd, pathname, mode, dev));
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mac_selinux_create_file_clear();
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if (r < 0)
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return r;
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return mac_smack_fix_full(dirfd, pathname, NULL, 0);
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}
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int btrfs_subvol_make_label(const char *path, LabelContext *label_context) {
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int r;
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assert(path);
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r = mac_selinux_create_file_prepare(path, S_IFDIR, label_context);
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if (r < 0)
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return r;
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r = btrfs_subvol_make(AT_FDCWD, path);
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mac_selinux_create_file_clear();
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if (r < 0)
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return r;
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return mac_smack_fix(path, 0);
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}
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int mac_label_context_new(const char *root, LabelContext **ret) {
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assert(ret);
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if (empty_or_root(root)) {
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*ret = NULL;
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return 0;
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}
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return mac_selinux_label_context_new(root, ret);
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}
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LabelContext* mac_label_context_free(LabelContext *c) {
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return mac_selinux_label_context_free(c);
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}
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static int init_internal(bool lazy) {
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int r;
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assert(!(mac_selinux_use() && mac_smack_use()));
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if (lazy)
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r = mac_selinux_init_lazy();
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else
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r = mac_selinux_init();
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if (r < 0)
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return r;
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return mac_smack_init();
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}
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int mac_init_lazy(void) {
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return init_internal(/* lazy= */ true);
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}
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int mac_init(void) {
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return init_internal(/* lazy= */ false);
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}
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