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-rw-r--r--include/linux/key.h516
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diff --git a/include/linux/key.h b/include/linux/key.h
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+++ b/include/linux/key.h
@@ -0,0 +1,516 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Authentication token and access key management
+ *
+ * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * See Documentation/security/keys/core.rst for information on keys/keyrings.
+ */
+
+#ifndef _LINUX_KEY_H
+#define _LINUX_KEY_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/rcupdate.h>
+#include <linux/sysctl.h>
+#include <linux/rwsem.h>
+#include <linux/atomic.h>
+#include <linux/assoc_array.h>
+#include <linux/refcount.h>
+#include <linux/time64.h>
+
+#ifdef __KERNEL__
+#include <linux/uidgid.h>
+
+/* key handle serial number */
+typedef int32_t key_serial_t;
+
+/* key handle permissions mask */
+typedef uint32_t key_perm_t;
+
+struct key;
+struct net;
+
+#ifdef CONFIG_KEYS
+
+#undef KEY_DEBUGGING
+
+#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
+#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
+#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
+#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
+#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
+#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
+#define KEY_POS_ALL 0x3f000000
+
+#define KEY_USR_VIEW 0x00010000 /* user permissions... */
+#define KEY_USR_READ 0x00020000
+#define KEY_USR_WRITE 0x00040000
+#define KEY_USR_SEARCH 0x00080000
+#define KEY_USR_LINK 0x00100000
+#define KEY_USR_SETATTR 0x00200000
+#define KEY_USR_ALL 0x003f0000
+
+#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
+#define KEY_GRP_READ 0x00000200
+#define KEY_GRP_WRITE 0x00000400
+#define KEY_GRP_SEARCH 0x00000800
+#define KEY_GRP_LINK 0x00001000
+#define KEY_GRP_SETATTR 0x00002000
+#define KEY_GRP_ALL 0x00003f00
+
+#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
+#define KEY_OTH_READ 0x00000002
+#define KEY_OTH_WRITE 0x00000004
+#define KEY_OTH_SEARCH 0x00000008
+#define KEY_OTH_LINK 0x00000010
+#define KEY_OTH_SETATTR 0x00000020
+#define KEY_OTH_ALL 0x0000003f
+
+#define KEY_PERM_UNDEF 0xffffffff
+
+/*
+ * The permissions required on a key that we're looking up.
+ */
+enum key_need_perm {
+ KEY_NEED_UNSPECIFIED, /* Needed permission unspecified */
+ KEY_NEED_VIEW, /* Require permission to view attributes */
+ KEY_NEED_READ, /* Require permission to read content */
+ KEY_NEED_WRITE, /* Require permission to update / modify */
+ KEY_NEED_SEARCH, /* Require permission to search (keyring) or find (key) */
+ KEY_NEED_LINK, /* Require permission to link */
+ KEY_NEED_SETATTR, /* Require permission to change attributes */
+ KEY_NEED_UNLINK, /* Require permission to unlink key */
+ KEY_SYSADMIN_OVERRIDE, /* Special: override by CAP_SYS_ADMIN */
+ KEY_AUTHTOKEN_OVERRIDE, /* Special: override by possession of auth token */
+ KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */
+};
+
+enum key_lookup_flag {
+ KEY_LOOKUP_CREATE = 0x01,
+ KEY_LOOKUP_PARTIAL = 0x02,
+ KEY_LOOKUP_ALL = (KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL),
+};
+
+struct seq_file;
+struct user_struct;
+struct signal_struct;
+struct cred;
+
+struct key_type;
+struct key_owner;
+struct key_tag;
+struct keyring_list;
+struct keyring_name;
+
+struct key_tag {
+ struct rcu_head rcu;
+ refcount_t usage;
+ bool removed; /* T when subject removed */
+};
+
+struct keyring_index_key {
+ /* [!] If this structure is altered, the union in struct key must change too! */
+ unsigned long hash; /* Hash value */
+ union {
+ struct {
+#ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */
+ u16 desc_len;
+ char desc[sizeof(long) - 2]; /* First few chars of description */
+#else
+ char desc[sizeof(long) - 2]; /* First few chars of description */
+ u16 desc_len;
+#endif
+ };
+ unsigned long x;
+ };
+ struct key_type *type;
+ struct key_tag *domain_tag; /* Domain of operation */
+ const char *description;
+};
+
+union key_payload {
+ void __rcu *rcu_data0;
+ void *data[4];
+};
+
+/*****************************************************************************/
+/*
+ * key reference with possession attribute handling
+ *
+ * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
+ * defined. This is because we abuse the bottom bit of the reference to carry a
+ * flag to indicate whether the calling process possesses that key in one of
+ * its keyrings.
+ *
+ * the key_ref_t has been made a separate type so that the compiler can reject
+ * attempts to dereference it without proper conversion.
+ *
+ * the three functions are used to assemble and disassemble references
+ */
+typedef struct __key_reference_with_attributes *key_ref_t;
+
+static inline key_ref_t make_key_ref(const struct key *key,
+ bool possession)
+{
+ return (key_ref_t) ((unsigned long) key | possession);
+}
+
+static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
+{
+ return (struct key *) ((unsigned long) key_ref & ~1UL);
+}
+
+static inline bool is_key_possessed(const key_ref_t key_ref)
+{
+ return (unsigned long) key_ref & 1UL;
+}
+
+typedef int (*key_restrict_link_func_t)(struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restriction_key);
+
+struct key_restriction {
+ key_restrict_link_func_t check;
+ struct key *key;
+ struct key_type *keytype;
+};
+
+enum key_state {
+ KEY_IS_UNINSTANTIATED,
+ KEY_IS_POSITIVE, /* Positively instantiated */
+};
+
+/*****************************************************************************/
+/*
+ * authentication token / access credential / keyring
+ * - types of key include:
+ * - keyrings
+ * - disk encryption IDs
+ * - Kerberos TGTs and tickets
+ */
+struct key {
+ refcount_t usage; /* number of references */
+ key_serial_t serial; /* key serial number */
+ union {
+ struct list_head graveyard_link;
+ struct rb_node serial_node;
+ };
+#ifdef CONFIG_KEY_NOTIFICATIONS
+ struct watch_list *watchers; /* Entities watching this key for changes */
+#endif
+ struct rw_semaphore sem; /* change vs change sem */
+ struct key_user *user; /* owner of this key */
+ void *security; /* security data for this key */
+ union {
+ time64_t expiry; /* time at which key expires (or 0) */
+ time64_t revoked_at; /* time at which key was revoked */
+ };
+ time64_t last_used_at; /* last time used for LRU keyring discard */
+ kuid_t uid;
+ kgid_t gid;
+ key_perm_t perm; /* access permissions */
+ unsigned short quotalen; /* length added to quota */
+ unsigned short datalen; /* payload data length
+ * - may not match RCU dereferenced payload
+ * - payload should contain own length
+ */
+ short state; /* Key state (+) or rejection error (-) */
+
+#ifdef KEY_DEBUGGING
+ unsigned magic;
+#define KEY_DEBUG_MAGIC 0x18273645u
+#endif
+
+ unsigned long flags; /* status flags (change with bitops) */
+#define KEY_FLAG_DEAD 0 /* set if key type has been deleted */
+#define KEY_FLAG_REVOKED 1 /* set if key had been revoked */
+#define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */
+#define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */
+#define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */
+#define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */
+#define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */
+#define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */
+#define KEY_FLAG_KEEP 8 /* set if key should not be removed */
+#define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */
+
+ /* the key type and key description string
+ * - the desc is used to match a key against search criteria
+ * - it should be a printable string
+ * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
+ */
+ union {
+ struct keyring_index_key index_key;
+ struct {
+ unsigned long hash;
+ unsigned long len_desc;
+ struct key_type *type; /* type of key */
+ struct key_tag *domain_tag; /* Domain of operation */
+ char *description;
+ };
+ };
+
+ /* key data
+ * - this is used to hold the data actually used in cryptography or
+ * whatever
+ */
+ union {
+ union key_payload payload;
+ struct {
+ /* Keyring bits */
+ struct list_head name_link;
+ struct assoc_array keys;
+ };
+ };
+
+ /* This is set on a keyring to restrict the addition of a link to a key
+ * to it. If this structure isn't provided then it is assumed that the
+ * keyring is open to any addition. It is ignored for non-keyring
+ * keys. Only set this value using keyring_restrict(), keyring_alloc(),
+ * or key_alloc().
+ *
+ * This is intended for use with rings of trusted keys whereby addition
+ * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION
+ * overrides this, allowing the kernel to add extra keys without
+ * restriction.
+ */
+ struct key_restriction *restrict_link;
+};
+
+extern struct key *key_alloc(struct key_type *type,
+ const char *desc,
+ kuid_t uid, kgid_t gid,
+ const struct cred *cred,
+ key_perm_t perm,
+ unsigned long flags,
+ struct key_restriction *restrict_link);
+
+
+#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
+#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
+#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
+#define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */
+#define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */
+#define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */
+#define KEY_ALLOC_SET_KEEP 0x0020 /* Set the KEEP flag on the key/keyring */
+
+extern void key_revoke(struct key *key);
+extern void key_invalidate(struct key *key);
+extern void key_put(struct key *key);
+extern bool key_put_tag(struct key_tag *tag);
+extern void key_remove_domain(struct key_tag *domain_tag);
+
+static inline struct key *__key_get(struct key *key)
+{
+ refcount_inc(&key->usage);
+ return key;
+}
+
+static inline struct key *key_get(struct key *key)
+{
+ return key ? __key_get(key) : key;
+}
+
+static inline void key_ref_put(key_ref_t key_ref)
+{
+ key_put(key_ref_to_ptr(key_ref));
+}
+
+extern struct key *request_key_tag(struct key_type *type,
+ const char *description,
+ struct key_tag *domain_tag,
+ const char *callout_info);
+
+extern struct key *request_key_rcu(struct key_type *type,
+ const char *description,
+ struct key_tag *domain_tag);
+
+extern struct key *request_key_with_auxdata(struct key_type *type,
+ const char *description,
+ struct key_tag *domain_tag,
+ const void *callout_info,
+ size_t callout_len,
+ void *aux);
+
+/**
+ * request_key - Request a key and wait for construction
+ * @type: Type of key.
+ * @description: The searchable description of the key.
+ * @callout_info: The data to pass to the instantiation upcall (or NULL).
+ *
+ * As for request_key_tag(), but with the default global domain tag.
+ */
+static inline struct key *request_key(struct key_type *type,
+ const char *description,
+ const char *callout_info)
+{
+ return request_key_tag(type, description, NULL, callout_info);
+}
+
+#ifdef CONFIG_NET
+/**
+ * request_key_net - Request a key for a net namespace and wait for construction
+ * @type: Type of key.
+ * @description: The searchable description of the key.
+ * @net: The network namespace that is the key's domain of operation.
+ * @callout_info: The data to pass to the instantiation upcall (or NULL).
+ *
+ * As for request_key() except that it does not add the returned key to a
+ * keyring if found, new keys are always allocated in the user's quota, the
+ * callout_info must be a NUL-terminated string and no auxiliary data can be
+ * passed. Only keys that operate the specified network namespace are used.
+ *
+ * Furthermore, it then works as wait_for_key_construction() to wait for the
+ * completion of keys undergoing construction with a non-interruptible wait.
+ */
+#define request_key_net(type, description, net, callout_info) \
+ request_key_tag(type, description, net->key_domain, callout_info)
+
+/**
+ * request_key_net_rcu - Request a key for a net namespace under RCU conditions
+ * @type: Type of key.
+ * @description: The searchable description of the key.
+ * @net: The network namespace that is the key's domain of operation.
+ *
+ * As for request_key_rcu() except that only keys that operate the specified
+ * network namespace are used.
+ */
+#define request_key_net_rcu(type, description, net) \
+ request_key_rcu(type, description, net->key_domain)
+#endif /* CONFIG_NET */
+
+extern int wait_for_key_construction(struct key *key, bool intr);
+
+extern int key_validate(const struct key *key);
+
+extern key_ref_t key_create_or_update(key_ref_t keyring,
+ const char *type,
+ const char *description,
+ const void *payload,
+ size_t plen,
+ key_perm_t perm,
+ unsigned long flags);
+
+extern int key_update(key_ref_t key,
+ const void *payload,
+ size_t plen);
+
+extern int key_link(struct key *keyring,
+ struct key *key);
+
+extern int key_move(struct key *key,
+ struct key *from_keyring,
+ struct key *to_keyring,
+ unsigned int flags);
+
+extern int key_unlink(struct key *keyring,
+ struct key *key);
+
+extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
+ const struct cred *cred,
+ key_perm_t perm,
+ unsigned long flags,
+ struct key_restriction *restrict_link,
+ struct key *dest);
+
+extern int restrict_link_reject(struct key *keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restriction_key);
+
+extern int keyring_clear(struct key *keyring);
+
+extern key_ref_t keyring_search(key_ref_t keyring,
+ struct key_type *type,
+ const char *description,
+ bool recurse);
+
+extern int keyring_add_key(struct key *keyring,
+ struct key *key);
+
+extern int keyring_restrict(key_ref_t keyring, const char *type,
+ const char *restriction);
+
+extern struct key *key_lookup(key_serial_t id);
+
+static inline key_serial_t key_serial(const struct key *key)
+{
+ return key ? key->serial : 0;
+}
+
+extern void key_set_timeout(struct key *, unsigned);
+
+extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
+ enum key_need_perm need_perm);
+extern void key_free_user_ns(struct user_namespace *);
+
+static inline short key_read_state(const struct key *key)
+{
+ /* Barrier versus mark_key_instantiated(). */
+ return smp_load_acquire(&key->state);
+}
+
+/**
+ * key_is_positive - Determine if a key has been positively instantiated
+ * @key: The key to check.
+ *
+ * Return true if the specified key has been positively instantiated, false
+ * otherwise.
+ */
+static inline bool key_is_positive(const struct key *key)
+{
+ return key_read_state(key) == KEY_IS_POSITIVE;
+}
+
+static inline bool key_is_negative(const struct key *key)
+{
+ return key_read_state(key) < 0;
+}
+
+#define dereference_key_rcu(KEY) \
+ (rcu_dereference((KEY)->payload.rcu_data0))
+
+#define dereference_key_locked(KEY) \
+ (rcu_dereference_protected((KEY)->payload.rcu_data0, \
+ rwsem_is_locked(&((struct key *)(KEY))->sem)))
+
+#define rcu_assign_keypointer(KEY, PAYLOAD) \
+do { \
+ rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \
+} while (0)
+
+#ifdef CONFIG_SYSCTL
+extern struct ctl_table key_sysctls[];
+#endif
+/*
+ * the userspace interface
+ */
+extern int install_thread_keyring_to_cred(struct cred *cred);
+extern void key_fsuid_changed(struct cred *new_cred);
+extern void key_fsgid_changed(struct cred *new_cred);
+extern void key_init(void);
+
+#else /* CONFIG_KEYS */
+
+#define key_validate(k) 0
+#define key_serial(k) 0
+#define key_get(k) ({ NULL; })
+#define key_revoke(k) do { } while(0)
+#define key_invalidate(k) do { } while(0)
+#define key_put(k) do { } while(0)
+#define key_ref_put(k) do { } while(0)
+#define make_key_ref(k, p) NULL
+#define key_ref_to_ptr(k) NULL
+#define is_key_possessed(k) 0
+#define key_fsuid_changed(c) do { } while(0)
+#define key_fsgid_changed(c) do { } while(0)
+#define key_init() do { } while(0)
+#define key_free_user_ns(ns) do { } while(0)
+#define key_remove_domain(d) do { } while(0)
+
+#endif /* CONFIG_KEYS */
+#endif /* __KERNEL__ */
+#endif /* _LINUX_KEY_H */
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