/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2011 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <assert.h> #include <sys/acl.h> #include <acl/libacl.h> #include <errno.h> #include <string.h> #include "logind-acl.h" #include "util.h" static int find_acl(acl_t acl, uid_t uid, acl_entry_t *entry) { acl_entry_t i; int found; assert(acl); assert(entry); for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i); found > 0; found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) { acl_tag_t tag; uid_t *u; bool b; if (acl_get_tag_type(i, &tag) < 0) return -errno; if (tag != ACL_USER) continue; u = acl_get_qualifier(i); if (!u) return -errno; b = *u == uid; acl_free(u); if (b) { *entry = i; return 1; } } if (found < 0) return -errno; return 0; } static int flush_acl(acl_t acl) { acl_entry_t i; int found; bool changed = false; assert(acl); for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i); found > 0; found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) { acl_tag_t tag; if (acl_get_tag_type(i, &tag) < 0) return -errno; if (tag != ACL_USER) continue; if (acl_delete_entry(acl, i) < 0) return -errno; changed = true; } if (found < 0) return -errno; return changed; } int devnode_acl(const char *path, bool flush, bool del, uid_t old_uid, bool add, uid_t new_uid) { acl_t acl; int r = 0; bool changed = false; assert(path); acl = acl_get_file(path, ACL_TYPE_ACCESS); if (!acl) return -errno; if (flush) { r = flush_acl(acl); if (r < 0) goto finish; if (r > 0) changed = true; } else if (del && old_uid > 0) { acl_entry_t entry; r = find_acl(acl, old_uid, &entry); if (r < 0) goto finish; if (r > 0) { if (acl_delete_entry(acl, entry) < 0) { r = -errno; goto finish; } changed = true; } } if (add && new_uid > 0) { acl_entry_t entry; acl_permset_t permset; int rd, wt; r = find_acl(acl, new_uid, &entry); if (r < 0) goto finish; if (r == 0) { if (acl_create_entry(&acl, &entry) < 0) { r = -errno; goto finish; } if (acl_set_tag_type(entry, ACL_USER) < 0 || acl_set_qualifier(entry, &new_uid) < 0) { r = -errno; goto finish; } } if (acl_get_permset(entry, &permset) < 0) { r = -errno; goto finish; } rd = acl_get_perm(permset, ACL_READ); if (rd < 0) { r = -errno; goto finish; } wt = acl_get_perm(permset, ACL_WRITE); if (wt < 0) { r = -errno; goto finish; } if (!rd || !wt) { if (acl_add_perm(permset, ACL_READ|ACL_WRITE) < 0) { r = -errno; goto finish; } changed = true; } } if (!changed) goto finish; if (acl_calc_mask(&acl) < 0) { r = -errno; goto finish; } if (acl_set_file(path, ACL_TYPE_ACCESS, acl) < 0) { r = -errno; goto finish; } r = 0; finish: acl_free(acl); return r; } int devnode_acl_all(struct udev *udev, const char *seat, bool flush, bool del, uid_t old_uid, bool add, uid_t new_uid) { struct udev_list_entry *item = NULL, *first = NULL; struct udev_enumerate *e; int r; assert(udev); if (isempty(seat)) seat = "seat0"; e = udev_enumerate_new(udev); if (!e) return -ENOMEM; /* We can only match by one tag in libudev. We choose * "uaccess" for that. If we could match for two tags here we * could add the seat name as second match tag, but this would * be hardly optimizable in libudev, and hence checking the * second tag manually in our loop is a good solution. */ r = udev_enumerate_add_match_tag(e, "uaccess"); if (r < 0) goto finish; r = udev_enumerate_scan_devices(e); if (r < 0) goto finish; first = udev_enumerate_get_list_entry(e); udev_list_entry_foreach(item, first) { struct udev_device *d; const char *node, *sn; d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); if (!d) { r = -ENOMEM; goto finish; } sn = udev_device_get_property_value(d, "ID_SEAT"); if (isempty(sn)) sn = "seat0"; if (!streq(seat, sn)) { udev_device_unref(d); continue; } node = udev_device_get_devnode(d); if (!node) { /* In case people mistag devices with nodes, we need to ignore this */ udev_device_unref(d); continue; } log_debug("Fixing up %s for seat %s...", node, sn); r = devnode_acl(node, flush, del, old_uid, add, new_uid); udev_device_unref(d); if (r < 0) goto finish; } finish: if (e) udev_enumerate_unref(e); return r; }