kernel/linux.git/security/keys/key.c, branch v6.12.80

keys: Fix UAF in key_put()

2025-03-28T21:03:30+00:00

commit 75845c6c1a64483e9985302793dbf0dfa5f71e32 upstream. Once a key's reference count has been reduced to 0, the garbage collector thread may destroy it at any time and so key_put() is not allowed to touch the key after that point. The most key_put() is normally allowed to do is to touch key_gc_work as that's a static global variable. However, in an effort to speed up the reclamation of quota, this is now done in key_put() once the key's usage is reduced to 0 - but now the code is looking at the key after the deadline, which is forbidden. Fix this by using a flag to indicate that a key can be gc'd now rather than looking at the key's refcount in the garbage collector. Fixes: 9578e327b2b4 ("keys: update key quotas in key_put()") Reported-by: syzbot+6105ffc1ded71d194d6d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/673b6aec.050a0220.87769.004a.GAE@google.com/ Signed-off-by: David Howells Tested-by: syzbot+6105ffc1ded71d194d6d@syzkaller.appspotmail.com Reviewed-by: Oleg Nesterov Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman

keys: Fix overwrite of key expiration on instantiation

2024-05-09T13:28:58+00:00

The expiry time of a key is unconditionally overwritten during instantiation, defaulting to turn it permanent. This causes a problem for DNS resolution as the expiration set by user-space is overwritten to TIME64_MAX, disabling further DNS updates. Fix this by restoring the condition that key_set_expiry is only called when the pre-parser sets a specific expiry. Fixes: 39299bdd2546 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry") Signed-off-by: Silvio Gissi cc: David Howells cc: Hazem Mohamed Abuelfotoh cc: linux-afs@lists.infradead.org cc: linux-cifs@vger.kernel.org cc: keyrings@vger.kernel.org cc: netdev@vger.kernel.org cc: stable@vger.kernel.org Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

keys: update key quotas in key_put()

2024-05-09T13:28:58+00:00

Delaying key quotas update when key's refcount reaches 0 in key_put() has been causing some issues in fscrypt testing, specifically in fstest generic/581. This commit fixes this test flakiness by dealing with the quotas immediately, and leaving all the other clean-ups to the key garbage collector. This is done by moving the updates to the qnkeys and qnbytes fields in struct key_user from key_gc_unused_keys() into key_put(). Unfortunately, this also means that we need to switch to the irq-version of the spinlock that protects these fields and use spin_lock_{irqsave,irqrestore} in all the code that touches these fields. Signed-off-by: Luis Henriques Reviewed-by: Jarkko Sakkinen Acked-by: David Howells Signed-off-by: Jarkko Sakkinen

ima: Move to LSM infrastructure

2024-02-16T04:43:46+00:00

Move hardcoded IMA function calls (not appraisal-specific functions) from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'ima' (at the end of the LSM list and always enabled like 'integrity'). Having IMA before EVM in the Makefile is sufficient to preserve the relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM, and thus the order of IMA and EVM function calls as when they were hardcoded. Make moved functions as static (except ima_post_key_create_or_update(), which is not in ima_main.c), and register them as implementation of the respective hooks in the new function init_ima_lsm(). Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook path_post_mknod is always available and ima_post_path_mknod() is always executed to mark files as new, as before the move. A slight difference is that IMA and EVM functions registered for the inode_post_setattr, inode_post_removexattr, path_post_mknod, inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl won't be executed for private inodes. Since those inodes are supposed to be fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub and kernel-internal tmpfs files. Conditionally register ima_post_key_create_or_update() if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled. Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c. Signed-off-by: Roberto Sassu Acked-by: Chuck Lever Acked-by: Casey Schaufler Acked-by: Christian Brauner Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Acked-by: Mimi Zohar Signed-off-by: Paul Moore

security: Introduce key_post_create_or_update hook

2024-02-16T04:43:45+00:00

In preparation for moving IMA and EVM to the LSM infrastructure, introduce the key_post_create_or_update hook. Depending on policy, IMA measures the key content after creation or update, so that remote verifiers are aware of the operation. Other LSMs could similarly take some action after successful key creation or update. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger Acked-by: Casey Schaufler Reviewed-by: Mimi Zohar Signed-off-by: Paul Moore

keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry

2023-12-21T13:47:38+00:00

If a key has an expiration time, then when that time passes, the key is left around for a certain amount of time before being collected (5 mins by default) so that EKEYEXPIRED can be returned instead of ENOKEY. This is a problem for DNS keys because we want to redo the DNS lookup immediately at that point. Fix this by allowing key types to be marked such that keys of that type don't have this extra period, but are reclaimed as soon as they expire and turn this on for dns_resolver-type keys. To make this easier to handle, key->expiry is changed to be permanent if TIME64_MAX rather than 0. Furthermore, give such new-style negative DNS results a 1s default expiry if no other expiry time is set rather than allowing it to stick around indefinitely. This shouldn't be zero as ls will follow a failing stat call immediately with a second with AT_SYMLINK_NOFOLLOW added. Fixes: 1a4240f4764a ("DNS: Separate out CIFS DNS Resolver code") Signed-off-by: David Howells Tested-by: Markus Suvanto cc: Wang Lei cc: Jeff Layton cc: Steve French cc: Marc Dionne cc: Jarkko Sakkinen cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: linux-afs@lists.infradead.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: keyrings@vger.kernel.org cc: netdev@vger.kernel.org

security/keys: export key_lookup()

2023-10-11T17:11:54+00:00

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 Reviewed-by: Sagi Grimberg Acked-by: David Howells Signed-off-by: Keith Busch

KEYS: Add new function key_create()

2023-02-13T08:11:20+00:00

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 Signed-off-by: Jarkko Sakkinen

certs: Fix blacklist flag type confusion

2021-01-21T16:16:10+00:00

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 Signed-off-by: David Howells cc: Mickaël Salaün cc: Mimi Zohar Cc: David Woodhouse

keys: Provide the original description to the key preparser

2020-11-23T18:09:29+00:00

Provide the proposed description (add key) or the original description (update/instantiate key) when preparsing a key so that the key type can validate it against the data. This is important for rxrpc server keys as we need to check that they have the right amount of key material present - and it's better to do that when the key is loaded rather than deep in trying to process a response packet. Signed-off-by: David Howells cc: Jarkko Sakkinen cc: keyrings@vger.kernel.org