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