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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168// SPDX-License-Identifier: GPL-2.0-or-later/* General persistent per-UID keyrings register * * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */
#include <linux/user_namespace.h>#include <linux/cred.h>
#include "internal.h"
unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */
/* * Create the persistent keyring register for the current user namespace. * * Called with the namespace's sem locked for writing. */static int key_create_persistent_register(struct user_namespace *ns){ struct key *reg = keyring_alloc(".persistent_register", KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ), KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); if (IS_ERR(reg)) return PTR_ERR(reg);
ns->persistent_keyring_register = reg; return 0;}
/* * Create the persistent keyring for the specified user. * * Called with the namespace's sem locked for writing. */static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid, struct keyring_index_key *index_key){ struct key *persistent; key_ref_t reg_ref, persistent_ref;
if (!ns->persistent_keyring_register) { long err = key_create_persistent_register(ns); if (err < 0) return ERR_PTR(err); } else { reg_ref = make_key_ref(ns->persistent_keyring_register, true); persistent_ref = find_key_to_update(reg_ref, index_key); if (persistent_ref) return persistent_ref; }
persistent = keyring_alloc(index_key->description, uid, INVALID_GID, current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ), KEY_ALLOC_NOT_IN_QUOTA, NULL, ns->persistent_keyring_register); if (IS_ERR(persistent)) return ERR_CAST(persistent);
return make_key_ref(persistent, true);}
/* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */static long key_get_persistent(struct user_namespace *ns, kuid_t uid, key_ref_t dest_ref){ struct keyring_index_key index_key; struct key *persistent; key_ref_t reg_ref, persistent_ref; char buf[32]; long ret;
/* Look in the register if it exists */ memset(&index_key, 0, sizeof(index_key)); index_key.type = &key_type_keyring; index_key.description = buf; index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid)); key_set_index_key(&index_key);
if (ns->persistent_keyring_register) { reg_ref = make_key_ref(ns->persistent_keyring_register, true); down_read(&ns->keyring_sem); persistent_ref = find_key_to_update(reg_ref, &index_key); up_read(&ns->keyring_sem);
if (persistent_ref) goto found; }
/* It wasn't in the register, so we'll need to create it. We might * also need to create the register. */ down_write(&ns->keyring_sem); persistent_ref = key_create_persistent(ns, uid, &index_key); up_write(&ns->keyring_sem); if (!IS_ERR(persistent_ref)) goto found;
return PTR_ERR(persistent_ref);
found: ret = key_task_permission(persistent_ref, current_cred(), KEY_NEED_LINK); if (ret == 0) { persistent = key_ref_to_ptr(persistent_ref); ret = key_link(key_ref_to_ptr(dest_ref), persistent); if (ret == 0) { key_set_timeout(persistent, persistent_keyring_expiry); ret = persistent->serial; } }
key_ref_put(persistent_ref); return ret;}
/* * Get the persistent keyring for a specific UID and link it to the nominated * keyring. */long keyctl_get_persistent(uid_t _uid, key_serial_t destid){ struct user_namespace *ns = current_user_ns(); key_ref_t dest_ref; kuid_t uid; long ret;
/* -1 indicates the current user */ if (_uid == (uid_t)-1) { uid = current_uid(); } else { uid = make_kuid(ns, _uid); if (!uid_valid(uid)) return -EINVAL;
/* You can only see your own persistent cache if you're not * sufficiently privileged. */ if (!uid_eq(uid, current_uid()) && !uid_eq(uid, current_euid()) && !ns_capable(ns, CAP_SETUID)) return -EPERM; }
/* There must be a destination keyring */ dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE); if (IS_ERR(dest_ref)) return PTR_ERR(dest_ref); if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) { ret = -ENOTDIR; goto out_put_dest; }
ret = key_get_persistent(ns, uid, dest_ref);
out_put_dest: key_ref_put(dest_ref); return ret;}