linux/certs
David Howells 4993e1f947 certs: Fix blacklist flag type confusion
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: 734114f878 ("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>
2021-01-21 16:16:10 +00:00
..
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
blacklist_hashes.c
blacklist_nohashes.c
blacklist.c certs: Fix blacklist flag type confusion 2021-01-21 16:16:10 +00:00
blacklist.h certs/blacklist: fix const confusion 2018-06-26 09:43:03 -07:00
Kconfig docs: Fix some broken references 2018-06-15 18:10:01 -03:00
Makefile kbuild: remove redundant target cleaning on failure 2019-01-06 09:46:51 +09:00
system_certificates.S export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
system_keyring.c PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00