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2023-10-11security/keys: export key_lookup()Hannes Reinecke
For in-kernel consumers one cannot readily assign a user (eg when running from a workqueue), so the normal key search permissions cannot be applied. This patch exports the 'key_lookup()' function for a simple lookup of keys without checking for permissions. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Keith Busch <kbusch@kernel.org>
2023-06-08sysctl: move security keys sysctl registration to its own fileLuis Chamberlain
The security keys sysctls are already declared on its own file, just move the sysctl registration to its own file to help avoid merge conflicts on sysctls.c, and help with clearing up sysctl.c further. This creates a small penalty of 23 bytes: ./scripts/bloat-o-meter vmlinux.1 vmlinux.2 add/remove: 2/0 grow/shrink: 0/1 up/down: 49/-26 (23) Function old new delta init_security_keys_sysctls - 33 +33 __pfx_init_security_keys_sysctls - 16 +16 sysctl_init_bases 85 59 -26 Total: Before=21256937, After=21256960, chg +0.00% But soon we'll be saving tons of bytes anyway, as we modify the sysctl registrations to use ARRAY_SIZE and so we get rid of all the empty array elements so let's just clean this up now. Reviewed-by: Paul Moore <paul@paul-moore.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-02-13KEYS: Add new function key_create()Thomas Weißschuh
key_create() works like key_create_or_update() but does not allow updating an existing key, instead returning ERR_PTR(-EEXIST). key_create() will be used by the blacklist keyring which should not create duplicate entries or update existing entries. Instead a dedicated message with appropriate severity will be logged. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2022-09-21KEYS: Move KEY_LOOKUP_ to include/linux/key.h and define KEY_LOOKUP_ALLRoberto Sassu
In preparation for the patch that introduces the bpf_lookup_user_key() eBPF kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to validate the kfunc parameters. Add them to enum key_lookup_flag, so that all the current ones and the ones defined in the future are automatically exported through BTF and available to eBPF programs. Also, add KEY_LOOKUP_ALL to the enum, with the logical OR of currently defined flags as value, to facilitate checking whether a variable contains only those flags. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/r/20220920075951.929132-7-roberto.sassu@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-01-21certs: Fix blacklist flag type confusionDavid Howells
KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() or key_alloc(), as these only take KEY_ALLOC_* flags. KEY_FLAG_KEEP has the same value as KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update() uses it. LSMs using the key_alloc hook don't check that flag. KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot write to the blacklist keyring, so it is not possible to remove a key/hash from it. Fix this by adding a KEY_ALLOC_SET_KEEP flag that tells key_alloc() to set KEY_FLAG_KEEP on the new key. blacklist_init() can then, correctly, pass this to keyring_alloc(). We can also use this in ima_mok_init() rather than setting the flag manually. Note that this doesn't fix an observable bug with the current implementation but it is required to allow addition of new hashes to the blacklist in the future without making it possible for them to be removed. Fixes: 734114f8782f ("KEYS: Add a system blacklist keyring") Reported-by: Mickaël Salaün <mic@linux.microsoft.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Mickaël Salaün <mic@linux.microsoft.com> cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Woodhouse <dwmw2@infradead.org>
2021-01-21keys: remove trailing semicolon in macro definitionTom Rix
The macro use will already have a semicolon. Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Ben Boeckel <mathstuf@gmail.com>
2020-05-19keys: Make the KEY_NEED_* perms an enum rather than a maskDavid Howells
Since the meaning of combining the KEY_NEED_* constants is undefined, make it so that you can't do that by turning them into an enum. The enum is also given some extra values to represent special circumstances, such as: (1) The '0' value is reserved and causes a warning to trap the parameter being unset. (2) The key is to be unlinked and we require no permissions on it, only the keyring, (this replaces the KEY_LOOKUP_FOR_UNLINK flag). (3) An override due to CAP_SYS_ADMIN. (4) An override due to an instantiation token being present. (5) The permissions check is being deferred to later key_permission() calls. The extra values give the opportunity for LSMs to audit these situations. [Note: This really needs overhauling so that lookup_user_key() tells key_task_permission() and the LSM what operation is being done and leaves it to those functions to decide how to map that onto the available permits. However, I don't really want to make these change in the middle of the notifications patchset.] Signed-off-by: David Howells <dhowells@redhat.com> cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> cc: Paul Moore <paul@paul-moore.com> cc: Stephen Smalley <stephen.smalley.work@gmail.com> cc: Casey Schaufler <casey@schaufler-ca.com> cc: keyrings@vger.kernel.org cc: selinux@vger.kernel.org
2020-05-19watch_queue: Add a key/keyring notification facilityDavid Howells
Add a key/keyring change notification facility whereby notifications about changes in key and keyring content and attributes can be received. Firstly, an event queue needs to be created: pipe2(fds, O_NOTIFICATION_PIPE); ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, 256); then a notification can be set up to report notifications via that queue: struct watch_notification_filter filter = { .nr_filters = 1, .filters = { [0] = { .type = WATCH_TYPE_KEY_NOTIFY, .subtype_filter[0] = UINT_MAX, }, }, }; ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter); keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01); After that, records will be placed into the queue when events occur in which keys are changed in some way. Records are of the following format: struct key_notification { struct watch_notification watch; __u32 key_id; __u32 aux; } *n; Where: n->watch.type will be WATCH_TYPE_KEY_NOTIFY. n->watch.subtype will indicate the type of event, such as NOTIFY_KEY_REVOKED. n->watch.info & WATCH_INFO_LENGTH will indicate the length of the record. n->watch.info & WATCH_INFO_ID will be the second argument to keyctl_watch_key(), shifted. n->key will be the ID of the affected key. n->aux will hold subtype-dependent information, such as the key being linked into the keyring specified by n->key in the case of NOTIFY_KEY_LINKED. Note that it is permissible for event records to be of variable length - or, at least, the length may be dependent on the subtype. Note also that the queue can be shared between multiple notifications of various types. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jamorris@linux.microsoft.com>
2019-09-02afs: Provide an RCU-capable key lookupDavid Howells
Provide an RCU-capable key lookup function. We don't want to call afs_request_key() in RCU-mode pathwalk as request_key() might sleep, even if we don't ask it to construct anything as it might find a key that is currently undergoing construction. Signed-off-by: David Howells <dhowells@redhat.com>
2019-08-19keys: Fix description sizeDavid Howells
The maximum key description size is 4095. Commit f771fde82051 ("keys: Simplify key description management") inadvertantly reduced that to 255 and made sizes between 256 and 4095 work weirdly, and any size whereby size & 255 == 0 would cause an assertion in __key_link_begin() at the following line: BUG_ON(index_key->desc_len == 0); This can be fixed by simply increasing the size of desc_len in struct keyring_index_key to a u16. Note the argument length test in keyutils only checked empty descriptions and descriptions with a size around the limit (ie. 4095) and not for all the values in between, so it missed this. This has been addressed and https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/commit/?id=066bf56807c26cd3045a25f355b34c1d8a20a5aa now exhaustively tests all possible lengths of type, description and payload and then some. The assertion failure looks something like: kernel BUG at security/keys/keyring.c:1245! ... RIP: 0010:__key_link_begin+0x88/0xa0 ... Call Trace: key_create_or_update+0x211/0x4b0 __x64_sys_add_key+0x101/0x200 do_syscall_64+0x5b/0x1e0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 It can be triggered by: keyctl add user "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" a @s Fixes: f771fde82051 ("keys: Simplify key description management") Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-10Revert "Merge tag 'keys-acl-20190703' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" This reverts merge 0f75ef6a9cff49ff612f7ce0578bced9d0b38325 (and thus effectively commits 7a1ade847596 ("keys: Provide KEYCTL_GRANT_PERMISSION") 2e12256b9a76 ("keys: Replace uid/gid/perm permissions checking with an ACL") that the merge brought in). It turns out that it breaks booting with an encrypted volume, and Eric biggers reports that it also breaks the fscrypt tests [1] and loading of in-kernel X.509 certificates [2]. The root cause of all the breakage is likely the same, but David Howells is off email so rather than try to work it out it's getting reverted in order to not impact the rest of the merge window. [1] https://lore.kernel.org/lkml/20190710011559.GA7973@sol.localdomain/ [2] https://lore.kernel.org/lkml/20190710013225.GB7973@sol.localdomain/ Link: https://lore.kernel.org/lkml/CAHk-=wjxoeMJfeBahnWH=9zShKp2bsVy527vo3_y8HfOdhwAAw@mail.gmail.com/ Reported-by: Eric Biggers <ebiggers@kernel.org> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-08Merge tag 'keys-acl-20190703' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull keyring ACL support from David Howells: "This changes the permissions model used by keys and keyrings to be based on an internal ACL by the following means: - Replace the permissions mask internally with an ACL that contains a list of ACEs, each with a specific subject with a permissions mask. Potted default ACLs are available for new keys and keyrings. ACE subjects can be macroised to indicate the UID and GID specified on the key (which remain). Future commits will be able to add additional subject types, such as specific UIDs or domain tags/namespaces. Also split a number of permissions to give finer control. Examples include splitting the revocation permit from the change-attributes permit, thereby allowing someone to be granted permission to revoke a key without allowing them to change the owner; also the ability to join a keyring is split from the ability to link to it, thereby stopping a process accessing a keyring by joining it and thus acquiring use of possessor permits. - Provide a keyctl to allow the granting or denial of one or more permits to a specific subject. Direct access to the ACL is not granted, and the ACL cannot be viewed" * tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: keys: Provide KEYCTL_GRANT_PERMISSION keys: Replace uid/gid/perm permissions checking with an ACL
2019-07-08Merge tag 'keys-namespace-20190627' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull keyring namespacing from David Howells: "These patches help make keys and keyrings more namespace aware. Firstly some miscellaneous patches to make the process easier: - Simplify key index_key handling so that the word-sized chunks assoc_array requires don't have to be shifted about, making it easier to add more bits into the key. - Cache the hash value in the key so that we don't have to calculate on every key we examine during a search (it involves a bunch of multiplications). - Allow keying_search() to search non-recursively. Then the main patches: - Make it so that keyring names are per-user_namespace from the point of view of KEYCTL_JOIN_SESSION_KEYRING so that they're not accessible cross-user_namespace. keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEYRING_NAME for this. - Move the user and user-session keyrings to the user_namespace rather than the user_struct. This prevents them propagating directly across user_namespaces boundaries (ie. the KEY_SPEC_* flags will only pick from the current user_namespace). - Make it possible to include the target namespace in which the key shall operate in the index_key. This will allow the possibility of multiple keys with the same description, but different target domains to be held in the same keyring. keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEY_TAG for this. - Make it so that keys are implicitly invalidated by removal of a domain tag, causing them to be garbage collected. - Institute a network namespace domain tag that allows keys to be differentiated by the network namespace in which they operate. New keys that are of a type marked 'KEY_TYPE_NET_DOMAIN' are assigned the network domain in force when they are created. - Make it so that the desired network namespace can be handed down into the request_key() mechanism. This allows AFS, NFS, etc. to request keys specific to the network namespace of the superblock. This also means that the keys in the DNS record cache are thenceforth namespaced, provided network filesystems pass the appropriate network namespace down into dns_query(). For DNS, AFS and NFS are good, whilst CIFS and Ceph are not. Other cache keyrings, such as idmapper keyrings, also need to set the domain tag - for which they need access to the network namespace of the superblock" * tag 'keys-namespace-20190627' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: keys: Pass the network namespace into request_key mechanism keys: Network namespace domain tag keys: Garbage collect keys for which the domain has been removed keys: Include target namespace in match criteria keys: Move the user and user-session keyrings to the user_namespace keys: Namespace keyring names keys: Add a 'recurse' flag for keyring searches keys: Cache the hash value to avoid lots of recalculation keys: Simplify key description management
2019-07-08Merge tag 'keys-request-20190626' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull request_key improvements from David Howells: "These are all request_key()-related, including a fix and some improvements: - Fix the lack of a Link permission check on a key found by request_key(), thereby enabling request_key() to link keys that don't grant this permission to the target keyring (which must still grant Write permission). Note that the key must be in the caller's keyrings already to be found. - Invalidate used request_key authentication keys rather than revoking them, so that they get cleaned up immediately rather than hanging around till the expiry time is passed. - Move the RCU locks outwards from the keyring search functions so that a request_key_rcu() can be provided. This can be called in RCU mode, so it can't sleep and can't upcall - but it can be called from LOOKUP_RCU pathwalk mode. - Cache the latest positive result of request_key*() temporarily in task_struct so that filesystems that make a lot of request_key() calls during pathwalk can take advantage of it to avoid having to redo the searching. This requires CONFIG_KEYS_REQUEST_CACHE=y. It is assumed that the key just found is likely to be used multiple times in each step in an RCU pathwalk, and is likely to be reused for the next step too. Note that the cleanup of the cache is done on TIF_NOTIFY_RESUME, just before userspace resumes, and on exit" * tag 'keys-request-20190626' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: keys: Kill off request_key_async{,_with_auxdata} keys: Cache result of request_key*() temporarily in task_struct keys: Provide request_key_rcu() keys: Move the RCU locks outwards from the keyring search functions keys: Invalidate used request_key authentication keys keys: Fix request_key() lack of Link perm check on found key
2019-07-08Merge tag 'keys-misc-20190619' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull misc keyring updates from David Howells: "These are some miscellaneous keyrings fixes and improvements: - Fix a bunch of warnings from sparse, including missing RCU bits and kdoc-function argument mismatches - Implement a keyctl to allow a key to be moved from one keyring to another, with the option of prohibiting key replacement in the destination keyring. - Grant Link permission to possessors of request_key_auth tokens so that upcall servicing daemons can more easily arrange things such that only the necessary auth key is passed to the actual service program, and not all the auth keys a daemon might possesss. - Improvement in lookup_user_key(). - Implement a keyctl to allow keyrings subsystem capabilities to be queried. The keyutils next branch has commits to make available, document and test the move-key and capabilities code: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log They're currently on the 'next' branch" * tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: keys: Add capability-checking keyctl function keys: Reuse keyring_index_key::desc_len in lookup_user_key() keys: Grant Link permission to possessers of request_key auth keys keys: Add a keyctl to move a key between keyrings keys: Hoist locking out of __key_link_begin() keys: Break bits out of key_unlink() keys: Change keyring_serialise_link_sem to a mutex keys: sparse: Fix kdoc mismatches keys: sparse: Fix incorrect RCU accesses keys: sparse: Fix key_fs[ug]id_changed()
2019-06-27keys: Replace uid/gid/perm permissions checking with an ACLDavid Howells
Replace the uid/gid/perm permissions checking on a key with an ACL to allow the SETATTR and SEARCH permissions to be split. This will also allow a greater range of subjects to represented. ============ WHY DO THIS? ============ The problem is that SETATTR and SEARCH cover a slew of actions, not all of which should be grouped together. For SETATTR, this includes actions that are about controlling access to a key: (1) Changing a key's ownership. (2) Changing a key's security information. (3) Setting a keyring's restriction. And actions that are about managing a key's lifetime: (4) Setting an expiry time. (5) Revoking a key. and (proposed) managing a key as part of a cache: (6) Invalidating a key. Managing a key's lifetime doesn't really have anything to do with controlling access to that key. Expiry time is awkward since it's more about the lifetime of the content and so, in some ways goes better with WRITE permission. It can, however, be set unconditionally by a process with an appropriate authorisation token for instantiating a key, and can also be set by the key type driver when a key is instantiated, so lumping it with the access-controlling actions is probably okay. As for SEARCH permission, that currently covers: (1) Finding keys in a keyring tree during a search. (2) Permitting keyrings to be joined. (3) Invalidation. But these don't really belong together either, since these actions really need to be controlled separately. Finally, there are number of special cases to do with granting the administrator special rights to invalidate or clear keys that I would like to handle with the ACL rather than key flags and special checks. =============== WHAT IS CHANGED =============== The SETATTR permission is split to create two new permissions: (1) SET_SECURITY - which allows the key's owner, group and ACL to be changed and a restriction to be placed on a keyring. (2) REVOKE - which allows a key to be revoked. The SEARCH permission is split to create: (1) SEARCH - which allows a keyring to be search and a key to be found. (2) JOIN - which allows a keyring to be joined as a session keyring. (3) INVAL - which allows a key to be invalidated. The WRITE permission is also split to create: (1) WRITE - which allows a key's content to be altered and links to be added, removed and replaced in a keyring. (2) CLEAR - which allows a keyring to be cleared completely. This is split out to make it possible to give just this to an administrator. (3) REVOKE - see above. Keys acquire ACLs which consist of a series of ACEs, and all that apply are unioned together. An ACE specifies a subject, such as: (*) Possessor - permitted to anyone who 'possesses' a key (*) Owner - permitted to the key owner (*) Group - permitted to the key group (*) Everyone - permitted to everyone Note that 'Other' has been replaced with 'Everyone' on the assumption that you wouldn't grant a permit to 'Other' that you wouldn't also grant to everyone else. Further subjects may be made available by later patches. The ACE also specifies a permissions mask. The set of permissions is now: VIEW Can view the key metadata READ Can read the key content WRITE Can update/modify the key content SEARCH Can find the key by searching/requesting LINK Can make a link to the key SET_SECURITY Can change owner, ACL, expiry INVAL Can invalidate REVOKE Can revoke JOIN Can join this keyring CLEAR Can clear this keyring The KEYCTL_SETPERM function is then deprecated. The KEYCTL_SET_TIMEOUT function then is permitted if SET_SECURITY is set, or if the caller has a valid instantiation auth token. The KEYCTL_INVALIDATE function then requires INVAL. The KEYCTL_REVOKE function then requires REVOKE. The KEYCTL_JOIN_SESSION_KEYRING function then requires JOIN to join an existing keyring. The JOIN permission is enabled by default for session keyrings and manually created keyrings only. ====================== BACKWARD COMPATIBILITY ====================== To maintain backward compatibility, KEYCTL_SETPERM will translate the permissions mask it is given into a new ACL for a key - unless KEYCTL_SET_ACL has been called on that key, in which case an error will be returned. It will convert possessor, owner, group and other permissions into separate ACEs, if each portion of the mask is non-zero. SETATTR permission turns on all of INVAL, REVOKE and SET_SECURITY. WRITE permission turns on WRITE, REVOKE and, if a keyring, CLEAR. JOIN is turned on if a keyring is being altered. The KEYCTL_DESCRIBE function translates the ACL back into a permissions mask to return depending on possessor, owner, group and everyone ACEs. It will make the following mappings: (1) INVAL, JOIN -> SEARCH (2) SET_SECURITY -> SETATTR (3) REVOKE -> WRITE if SETATTR isn't already set (4) CLEAR -> WRITE Note that the value subsequently returned by KEYCTL_DESCRIBE may not match the value set with KEYCTL_SETATTR. ======= TESTING ======= This passes the keyutils testsuite for all but a couple of tests: (1) tests/keyctl/dh_compute/badargs: The first wrong-key-type test now returns EOPNOTSUPP rather than ENOKEY as READ permission isn't removed if the type doesn't have ->read(). You still can't actually read the key. (2) tests/keyctl/permitting/valid: The view-other-permissions test doesn't work as Other has been replaced with Everyone in the ACL. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-27keys: Pass the network namespace into request_key mechanismDavid Howells
Create a request_key_net() function and use it to pass the network namespace domain tag into DNS revolver keys and rxrpc/AFS keys so that keys for different domains can coexist in the same keyring. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-afs@lists.infradead.org
2019-06-26keys: Garbage collect keys for which the domain has been removedDavid Howells
If a key operation domain (such as a network namespace) has been removed then attempt to garbage collect all the keys that use it. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-26keys: Include target namespace in match criteriaDavid Howells
Currently a key has a standard matching criteria of { type, description } and this is used to only allow keys with unique criteria in a keyring. This means, however, that you cannot have keys with the same type and description but a different target namespace in the same keyring. This is a potential problem for a containerised environment where, say, a container is made up of some parts of its mount space involving netfs superblocks from two different network namespaces. This is also a problem for shared system management keyrings such as the DNS records keyring or the NFS idmapper keyring that might contain keys from different network namespaces. Fix this by including a namespace component in a key's matching criteria. Keyring types are marked to indicate which, if any, namespace is relevant to keys of that type, and that namespace is set when the key is created from the current task's namespace set. The capability bit KEYCTL_CAPS1_NS_KEY_TAG is set if the kernel is employing this feature. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-26keys: Namespace keyring namesDavid Howells
Keyring names are held in a single global list that any process can pick from by means of keyctl_join_session_keyring (provided the keyring grants Search permission). This isn't very container friendly, however. Make the following changes: (1) Make default session, process and thread keyring names begin with a '.' instead of '_'. (2) Keyrings whose names begin with a '.' aren't added to the list. Such keyrings are system specials. (3) Replace the global list with per-user_namespace lists. A keyring adds its name to the list for the user_namespace that it is currently in. (4) When a user_namespace is deleted, it just removes itself from the keyring name list. The global keyring_name_lock is retained for accessing the name lists. This allows (4) to work. This can be tested by: # keyctl newring foo @s 995906392 # unshare -U $ keyctl show ... 995906392 --alswrv 65534 65534 \_ keyring: foo ... $ keyctl session foo Joined session keyring: 935622349 As can be seen, a new session keyring was created. The capability bit KEYCTL_CAPS1_NS_KEYRING_NAME is set if the kernel is employing this feature. Signed-off-by: David Howells <dhowells@redhat.com> cc: Eric W. Biederman <ebiederm@xmission.com>
2019-06-26keys: Add a 'recurse' flag for keyring searchesDavid Howells
Add a 'recurse' flag for keyring searches so that the flag can be omitted and recursion disabled, thereby allowing just the nominated keyring to be searched and none of the children. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-26keys: Cache the hash value to avoid lots of recalculationDavid Howells
Cache the hash of the key's type and description in the index key so that we're not recalculating it every time we look at a key during a search. The hash function does a bunch of multiplications, so evading those is probably worthwhile - especially as this is done for every key examined during a search. This also allows the methods used by assoc_array to get chunks of index-key to be simplified. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-26keys: Simplify key description managementDavid Howells
Simplify key description management by cramming the word containing the length with the first few chars of the description also. This simplifies the code that generates the index-key used by assoc_array. It should speed up key searching a bit too. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-26keys: Kill off request_key_async{,_with_auxdata}David Howells
Kill off request_key_async{,_with_auxdata}() as they're not currently used. Signed-off-by: David Howells <dhowells@redhat.com>
2019-06-19keys: Provide request_key_rcu()David Howells
Provide a request_key_rcu() function that can be used to request a key under RCU conditions. It can only search and check permissions; it cannot allocate a new key, upcall or wait for an upcall to complete. It may return a partially constructed key. Signed-off-by: David Howells <dhowells@redhat.com>
2019-05-30keys: Add a keyctl to move a key between keyringsDavid Howells
Add a keyctl to atomically move a link to a key from one keyring to another. The key must exist in "from" keyring and a flag can be given to cause the operation to fail if there's a matching key already in the "to" keyring. This can be done with: keyctl(KEYCTL_MOVE, key_serial_t key, key_serial_t from_keyring, key_serial_t to_keyring, unsigned int flags); The key being moved must grant Link permission and both keyrings must grant Write permission. flags should be 0 or KEYCTL_MOVE_EXCL, with the latter preventing displacement of a matching key from the "to" keyring. Signed-off-by: David Howells <dhowells@redhat.com>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
Based on 1 normalized pattern(s): this program 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22keys: sparse: Fix key_fs[ug]id_changed()David Howells
Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected accesses of tsk->cred, which is marked __rcu. Fix this by passing the new cred struct to these functions from commit_creds() rather than the task pointer. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jamorris@linux.microsoft.com>
2018-12-13keys: Export lookup_user_key to external usersDave Jiang
Export lookup_user_key() symbol in order to allow nvdimm passphrase update to retrieve user injected keys. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-11-15security: keys: Replace time_t/timespec with time64_tBaolin Wang
The 'struct key' will use 'time_t' which we try to remove in the kernel, since 'time_t' is not year 2038 safe on 32bit systems. Also the 'struct keyring_search_context' will use 'timespec' type to record current time, which is also not year 2038 safe on 32bit systems. Thus this patch replaces 'time_t' with 'time64_t' which is year 2038 safe for 'struct key', and replace 'timespec' with 'time64_t' for the 'struct keyring_search_context', since we only look at the the seconds part of 'timespec' variable. Moreover we also change the codes where using the 'time_t' and 'timespec', and we can get current time by ktime_get_real_seconds() instead of current_kernel_time(), and use 'TIME64_MAX' macro to initialize the 'time64_t' type variable. Especially in proc.c file, we have replaced 'unsigned long' and 'timespec' type with 'u64' and 'time64_t' type to save the timeout value, which means user will get one 'u64' type timeout value by issuing proc_keys_show() function. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <james.l.morris@oracle.com>
2017-10-18KEYS: Fix race between updating and finding a negative keyDavid Howells
Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection error into one field such that: (1) The instantiation state can be modified/read atomically. (2) The error can be accessed atomically with the state. (3) The error isn't stored unioned with the payload pointers. This deals with the problem that the state is spread over three different objects (two bits and a separate variable) and reading or updating them atomically isn't practical, given that not only can uninstantiated keys change into instantiated or rejected keys, but rejected keys can also turn into instantiated keys - and someone accessing the key might not be using any locking. The main side effect of this problem is that what was held in the payload may change, depending on the state. For instance, you might observe the key to be in the rejected state. You then read the cached error, but if the key semaphore wasn't locked, the key might've become instantiated between the two reads - and you might now have something in hand that isn't actually an error code. The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error code if the key is negatively instantiated. The key_is_instantiated() function is replaced with key_is_positive() to avoid confusion as negative keys are also 'instantiated'. Additionally, barriering is included: (1) Order payload-set before state-set during instantiation. (2) Order state-read before payload-read when using the key. Further separate barriering is necessary if RCU is being used to access the payload content after reading the payload pointers. Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data") Cc: stable@vger.kernel.org # v4.4+ Reported-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Eric Biggers <ebiggers@google.com>
2017-09-25KEYS: prevent creating a different user's keyringsEric Biggers
It was possible for an unprivileged user to create the user and user session keyrings for another user. For example: sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u keyctl add keyring _uid_ses.4000 "" @u sleep 15' & sleep 1 sudo -u '#4000' keyctl describe @u sudo -u '#4000' keyctl describe @us This is problematic because these "fake" keyrings won't have the right permissions. In particular, the user who created them first will own them and will have full access to them via the possessor permissions, which can be used to compromise the security of a user's keys: -4: alswrv-----v------------ 3000 0 keyring: _uid.4000 -5: alswrv-----v------------ 3000 0 keyring: _uid_ses.4000 Fix it by marking user and user session keyrings with a flag KEY_FLAG_UID_KEYRING. Then, when searching for a user or user session keyring by name, skip all keyrings that don't have the flag set. Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed") Cc: <stable@vger.kernel.org> [v2.6.26+] Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com>
2017-07-03Merge tag 'docs-4.13' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "There has been a fair amount of activity in the docs tree this time around. Highlights include: - Conversion of a bunch of security documentation into RST - The conversion of the remaining DocBook templates by The Amazing Mauro Machine. We can now drop the entire DocBook build chain. - The usual collection of fixes and minor updates" * tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits) scripts/kernel-doc: handle DECLARE_HASHTABLE Documentation: atomic_ops.txt is core-api/atomic_ops.rst Docs: clean up some DocBook loose ends Make the main documentation title less Geocities Docs: Use kernel-figure in vidioc-g-selection.rst Docs: fix table problems in ras.rst Docs: Fix breakage with Sphinx 1.5 and upper Docs: Include the Latex "ifthen" package doc/kokr/howto: Only send regression fixes after -rc1 docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters doc: Document suitability of IBM Verse for kernel development Doc: fix a markup error in coding-style.rst docs: driver-api: i2c: remove some outdated information Documentation: DMA API: fix a typo in a function name Docs: Insert missing space to separate link from text doc/ko_KR/memory-barriers: Update control-dependencies example Documentation, kbuild: fix typo "minimun" -> "minimum" docs: Fix some formatting issues in request-key.rst doc: ReSTify keys-trusted-encrypted.txt doc: ReSTify keys-request-key.txt ...
2017-06-09KEYS: sanitize key structs before freeingEric Biggers
While a 'struct key' itself normally does not contain sensitive information, Documentation/security/keys.txt actually encourages this: "Having a payload is not required; and the payload can, in fact, just be a value stored in the struct key itself." In case someone has taken this advice, or will take this advice in the future, zero the key structure before freeing it. We might as well, and as a bonus this could make it a bit more difficult for an adversary to determine which keys have recently been in use. This is safe because the key_jar cache does not use a constructor. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-05-18doc: ReSTify keys.txtKees Cook
This creates a new section in the security development index for kernel keys, and adjusts for ReST markup. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-04-04KEYS: Add KEYCTL_RESTRICT_KEYRINGMat Martineau
Keyrings recently gained restrict_link capabilities that allow individual keys to be validated prior to linking. This functionality was only available using internal kernel APIs. With the KEYCTL_RESTRICT_KEYRING command existing keyrings can be configured to check the content of keys before they are linked, and then allow or disallow linkage of that key to the keyring. To restrict a keyring, call: keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring, const char *type, const char *restriction) where 'type' is the name of a registered key type and 'restriction' is a string describing how key linkage is to be restricted. The restriction option syntax is specific to each key type. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-04KEYS: Use structure to capture key restriction function and dataMat Martineau
Replace struct key's restrict_link function pointer with a pointer to the new struct key_restriction. The structure contains pointers to the restriction function as well as relevant data for evaluating the restriction. The garbage collector checks restrict_link->keytype when key types are unregistered. Restrictions involving a removed key type are converted to use restrict_link_reject so that restrictions cannot be removed by unregistering key types. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-03KEYS: Add a key restriction structMat Martineau
Key link restrictions require restriction-specific data as well as a restriction-specific function pointer. As a first step toward replacing the restrict_link pointer in struct key, define a more general key_restriction structure that captures the required function, key, and key type pointers. Key type modules should not be pinned on account of this key type pointer because the pointer will be cleared by the garbage collector if the key type is unregistered. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-03KEYS: Split role of the keyring pointer for keyring restrict functionsMat Martineau
The first argument to the restrict_link_func_t functions was a keyring pointer. These functions are called by the key subsystem with this argument set to the destination keyring, but restrict_link_by_signature expects a pointer to the relevant trusted keyring. Restrict functions may need something other than a single struct key pointer to allow or reject key linkage, so the data used to make that decision (such as the trust keyring) is moved to a new, fourth argument. The first argument is now always the destination keyring. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-03KEYS: Use a typedef for restrict_link function pointersMat Martineau
This pointer type needs to be returned from a lookup function, and without a typedef the syntax gets cumbersome. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
2017-04-03security, keys: convert key.usage from atomic_t to refcount_tElena Reshetova
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-03-02KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()David Howells
rcu_dereference_key() and user_key_payload() are currently being used in two different, incompatible ways: (1) As a wrapper to rcu_dereference() - when only the RCU read lock used to protect the key. (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is used to protect the key and the may be being modified. Fix this by splitting both of the key wrappers to produce: (1) RCU accessors for keys when caller has the key semaphore locked: dereference_key_locked() user_key_payload_locked() (2) RCU accessors for keys when caller holds the RCU read lock: dereference_key_rcu() user_key_payload_rcu() This should fix following warning in the NFS idmapper =============================== [ INFO: suspicious RCU usage. ] 4.10.0 #1 Tainted: G W ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 1 lock held by mount.nfs/5987: #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] stack backtrace: CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 Call Trace: dump_stack+0xe8/0x154 (unreliable) lockdep_rcu_suspicious+0x140/0x190 nfs_idmap_get_key+0x380/0x420 [nfsv4] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] call_decode+0x29c/0x910 [sunrpc] __rpc_execute+0x140/0x8f0 [sunrpc] rpc_run_task+0x170/0x200 [sunrpc] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] nfs4_lookup_root+0xe0/0x350 [nfsv4] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] nfs4_find_root_sec+0xc4/0x100 [nfsv4] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] nfs4_get_rootfh+0x6c/0x190 [nfsv4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] nfs4_create_server+0x278/0x3c0 [nfsv4] nfs4_remote_mount+0x50/0xb0 [nfsv4] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 nfs_do_root_mount+0xb0/0x140 [nfsv4] nfs4_try_mount+0x60/0x100 [nfsv4] nfs_fs_mount+0x5ec/0xda0 [nfs] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 do_mount+0x254/0xf70 SyS_mount+0x94/0x100 system_call+0x38/0xe0 Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-04-11KEYS: Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTEDDavid Howells
Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer meaningful. Also we can drop the trusted flag from the preparse structure. Given this, we no longer need to pass the key flags through to restrict_link(). Further, we can now get rid of keyring_restrict_trusted_only() also. Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-11KEYS: Add a facility to restrict new links into a keyringDavid Howells
Add a facility whereby proposed new links to be added to a keyring can be vetted, permitting them to be rejected if necessary. This can be used to block public keys from which the signature cannot be verified or for which the signature verification fails. It could also be used to provide blacklisting. This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE. To this end: (1) A function pointer is added to the key struct that, if set, points to the vetting function. This is called as: int (*restrict_link)(struct key *keyring, const struct key_type *key_type, unsigned long key_flags, const union key_payload *key_payload), where 'keyring' will be the keyring being added to, key_type and key_payload will describe the key being added and key_flags[*] can be AND'ed with KEY_FLAG_TRUSTED. [*] This parameter will be removed in a later patch when KEY_FLAG_TRUSTED is removed. The function should return 0 to allow the link to take place or an error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the link. The pointer should not be set directly, but rather should be set through keyring_alloc(). Note that if called during add_key(), preparse is called before this method, but a key isn't actually allocated until after this function is called. (2) KEY_ALLOC_BYPASS_RESTRICTION is added. This can be passed to key_create_or_update() or key_instantiate_and_link() to bypass the restriction check. (3) KEY_FLAG_TRUSTED_ONLY is removed. The entire contents of a keyring with this restriction emplaced can be considered 'trustworthy' by virtue of being in the keyring when that keyring is consulted. (4) key_alloc() and keyring_alloc() take an extra argument that will be used to set restrict_link in the new key. This ensures that the pointer is set before the key is published, thus preventing a window of unrestrictedness. Normally this argument will be NULL. (5) As a temporary affair, keyring_restrict_trusted_only() is added. It should be passed to keyring_alloc() as the extra argument instead of setting KEY_FLAG_TRUSTED_ONLY on a keyring. This will be replaced in a later patch with functions that look in the appropriate places for authoritative keys. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2016-02-09KEYS: Add an alloc flag to convey the builtinness of a keyDavid Howells
Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN set rather than setting it after the fact. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15KEYS: prevent keys from being removed from specified keyringsMimi Zohar
Userspace should not be allowed to remove keys from certain keyrings (eg. blacklist), though the keys themselves can expire. This patch defines a new key flag named KEY_FLAG_KEEP to prevent userspace from being able to unlink, revoke, invalidate or timed out a key on a keyring. When this flag is set on the keyring, all keys subsequently added are flagged. In addition, when this flag is set, the keyring itself can not be cleared. Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: David Howells <dhowells@redhat.com>
2015-10-21KEYS: Merge the type-specific data with the payload dataDavid Howells
Merge the type-specific data with the payload data into one four-word chunk as it seems pointless to keep them separate. Use user_key_payload() for accessing the payloads of overloaded user-defined keys. Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-cifs@vger.kernel.org cc: ecryptfs@vger.kernel.org cc: linux-ext4@vger.kernel.org cc: linux-f2fs-devel@lists.sourceforge.net cc: linux-nfs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: linux-ima-devel@lists.sourceforge.net
2014-07-22Merge branch 'keys-fixes' into keys-nextDavid Howells
Signed-off-by: David Howells <dhowells@redhat.com>
2014-07-17KEYS: Allow special keys (eg. DNS results) to be invalidated by CAP_SYS_ADMINDavid Howells
Special kernel keys, such as those used to hold DNS results for AFS, CIFS and NFS and those used to hold idmapper results for NFS, used to be 'invalidateable' with key_revoke(). However, since the default permissions for keys were reduced: Commit: 96b5c8fea6c0861621051290d705ec2e971963f1 KEYS: Reduce initial permissions on keys it has become impossible to do this. Add a key flag (KEY_FLAG_ROOT_CAN_INVAL) that will permit a key to be invalidated by root. This should not be used for system keyrings as the garbage collector will try and remove any invalidate key. For system keyrings, KEY_FLAG_ROOT_CAN_CLEAR can be used instead. After this, from userspace, keyctl_invalidate() and "keyctl invalidate" can be used by any possessor of CAP_SYS_ADMIN (typically root) to invalidate DNS and idmapper keys. Invalidated keys are immediately garbage collected and will be immediately rerequested if needed again. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Steve Dickson <steved@redhat.com>
2014-07-17KEYS: validate certificate trust only with builtin keysDmitry Kasatkin
Instead of allowing public keys, with certificates signed by any key on the system trusted keyring, to be added to a trusted keyring, this patch further restricts the certificates to those signed only by builtin keys on the system keyring. This patch defines a new option 'builtin' for the kernel parameter 'keys_ownerid' to allow trust validation using builtin keys. Simplified Mimi's "KEYS: define an owner trusted keyring" patch Changelog v7: - rename builtin_keys to use_builtin_keys Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>