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>
Add the following:
(1) A new system keyring that is used to store information about
blacklisted certificates and signatures.
(2) A new key type (called 'blacklist') that is used to store a
blacklisted hash in its description as a hex string. The key accepts
no payload.
(3) The ability to configure a list of blacklisted hashes into the kernel
at build time. This is done by setting
CONFIG_SYSTEM_BLACKLIST_HASH_LIST to the filename of a list of hashes
that are in the form:
"<hash>", "<hash>", ..., "<hash>"
where each <hash> is a hex string representation of the hash and must
include all necessary leading zeros to pad the hash to the right size.
The above are enabled with CONFIG_SYSTEM_BLACKLIST_KEYRING.
Once the kernel is booted, the blacklist keyring can be listed:
root@andromeda ~]# keyctl show %:.blacklist
Keyring
723359729 ---lswrv 0 0 keyring: .blacklist
676257228 ---lswrv 0 0 \_ blacklist: 123412341234c55c1dcc601ab8e172917706aa32fb5eaf826813547fdf02dd46
The blacklist cannot currently be modified by userspace, but it will be
possible to load it, for example, from the UEFI blacklist database.
A later commit will make it possible to load blacklisted asymmetric keys in
here too.
Signed-off-by: David Howells <dhowells@redhat.com>
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>
Add a config option (IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY)
that, when enabled, allows keys to be added to the IMA keyrings by
userspace - with the restriction that each must be signed by a key in the
system trusted keyrings.
EPERM will be returned if this option is disabled, ENOKEY will be returned if
no authoritative key can be found and EKEYREJECTED will be returned if the
signature doesn't match. Other errors such as ENOPKG may also be returned.
If this new option is enabled, the builtin system keyring is searched, as is
the secondary system keyring if that is also enabled. Intermediate keys
between the builtin system keyring and the key being added can be added to
the secondary keyring (which replaces .ima_mok) to form a trust chain -
provided they are also validly signed by a key in one of the trusted keyrings.
The .ima_mok keyring is then removed and the IMA blacklist keyring gets its
own config option (IMA_BLACKLIST_KEYRING).
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Add a secondary system keyring that can be added to by root whilst the
system is running - provided the key being added is vouched for by a key
built into the kernel or already added to the secondary keyring.
Rename .system_keyring to .builtin_trusted_keys to distinguish it more
obviously from the new keyring (called .secondary_trusted_keys).
The new keyring needs to be enabled with CONFIG_SECONDARY_TRUSTED_KEYRING.
If the secondary keyring is enabled, a link is created from that to
.builtin_trusted_keys so that the the latter will automatically be searched
too if the secondary keyring is searched.
Signed-off-by: David Howells <dhowells@redhat.com>
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>
Move the point at which a key is determined to be trustworthy to
__key_link() so that we use the contents of the keyring being linked in to
to determine whether the key being linked in is trusted or not.
What is 'trusted' then becomes a matter of what's in the keyring.
Currently, the test is done when the key is parsed, but given that at that
point we can only sensibly refer to the contents of the system trusted
keyring, we can only use that as the basis for working out the
trustworthiness of a new key.
With this change, a trusted keyring is a set of keys that once the
trusted-only flag is set cannot be added to except by verification through
one of the contained keys.
Further, adding a key into a trusted keyring, whilst it might grant
trustworthiness in the context of that keyring, does not automatically
grant trustworthiness in the context of a second keyring to which it could
be secondarily linked.
To accomplish this, the authentication data associated with the key source
must now be retained. For an X.509 cert, this means the contents of the
AuthorityKeyIdentifier and the signature data.
If system keyrings are disabled then restrict_link_by_builtin_trusted()
resolves to restrict_link_reject(). The integrity digital signature code
still works correctly with this as it was previously using
KEY_FLAG_TRUSTED_ONLY, which doesn't permit anything to be added if there
is no system keyring against which trust can be determined.
Signed-off-by: David Howells <dhowells@redhat.com>
Generalise x509_request_asymmetric_key(). It doesn't really have any
dependencies on X.509 features as it uses generalised IDs and the
public_key structs that contain data extracted from X.509.
Signed-off-by: David Howells <dhowells@redhat.com>
Generalise system_verify_data() to provide access to internal content
through a callback. This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.
If external content is not required, NULL should be passed as data to the
function. If the callback is not required, that can be set to NULL.
The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.
Signed-off-by: David Howells <dhowells@redhat.com>
Allow authentication data to be stored in an asymmetric key in the 4th
element of the key payload and provide a way for it to be destroyed.
For the public key subtype, this will be a public_key_signature struct.
Signed-off-by: David Howells <dhowells@redhat.com>
In my original patch sealing with policy was done with dynamically
allocated buffer that I changed later into an array so the checks in
tpm2-cmd.c became invalid. This patch fixes the issue.
Fixes: 5beb0c435b ("keys, trusted: seal with a TPM2 authorization policy")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
TPM2 supports authorization policies, which are essentially
combinational logic statements repsenting the conditions where the data
can be unsealed based on the TPM state. This patch enables to use
authorization policies to seal trusted keys.
Two following new options have been added for trusted keys:
* 'policydigest=': provide an auth policy digest for sealing.
* 'policyhandle=': provide a policy session handle for unsealing.
If 'hash=' option is supplied after 'policydigest=' option, this
will result an error because the state of the option would become
mixed.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.
Added entry for sm3-256 to the following tables in order to support
TPM_ALG_SM3_256:
* hash_algo_name
* hash_digest_size
Includes support for the following hash algorithms:
* sha1
* sha256
* sha384
* sha512
* sm3-256
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
This option creates IMA MOK and blacklist keyrings. IMA MOK is an
intermediate keyring that sits between .system and .ima keyrings,
effectively forming a simple CA hierarchy. To successfully import a key
into .ima_mok it must be signed by a key which CA is in .system keyring.
On turn any key that needs to go in .ima keyring must be signed by CA in
either .system or .ima_mok keyrings. IMA MOK is empty at kernel boot.
IMA blacklist keyring contains all revoked IMA keys. It is consulted
before any other keyring. If the search is successful the requested
operation is rejected and error is returned to the caller.
Signed-off-by: Petko Manolov <petkan@mip-labs.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
trusted keys.
This patch implements basic sealing and unsealing functionality for
TPM 2.0:
* Seal with a parent key using a 20 byte auth value.
* Unseal with a parent key using a 20 byte auth value.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Moved struct trusted_key_options to trustes-type.h so that the fields
can be accessed from drivers/char/tpm.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
A PKCS#7 or CMS message can have per-signature authenticated attributes
that are digested as a lump and signed by the authorising key for that
signature. If such attributes exist, the content digest isn't itself
signed, but rather it is included in a special authattr which then
contributes to the signature.
Further, we already require the master message content type to be
pkcs7_signedData - but there's also a separate content type for the data
itself within the SignedData object and this must be repeated inside the
authattrs for each signer [RFC2315 9.2, RFC5652 11.1].
We should really validate the authattrs if they exist or forbid them
entirely as appropriate. To this end:
(1) Alter the PKCS#7 parser to reject any message that has more than one
signature where at least one signature has authattrs and at least one
that does not.
(2) Validate authattrs if they are present and strongly restrict them.
Only the following authattrs are permitted and all others are
rejected:
(a) contentType. This is checked to be an OID that matches the
content type in the SignedData object.
(b) messageDigest. This must match the crypto digest of the data.
(c) signingTime. If present, we check that this is a valid, parseable
UTCTime or GeneralTime and that the date it encodes fits within
the validity window of the matching X.509 cert.
(d) S/MIME capabilities. We don't check the contents.
(e) Authenticode SP Opus Info. We don't check the contents.
(f) Authenticode Statement Type. We don't check the contents.
The message is rejected if (a) or (b) are missing. If the message is
an Authenticode type, the message is rejected if (e) is missing; if
not Authenticode, the message is rejected if (d) - (f) are present.
The S/MIME capabilities authattr (d) unfortunately has to be allowed
to support kernels already signed by the pesign program. This only
affects kexec. sign-file suppresses them (CMS_NOSMIMECAP).
The message is also rejected if an authattr is given more than once or
if it contains more than one element in its set of values.
(3) Add a parameter to pkcs7_verify() to select one of the following
restrictions and pass in the appropriate option from the callers:
(*) VERIFYING_MODULE_SIGNATURE
This requires that the SignedData content type be pkcs7-data and
forbids authattrs. sign-file sets CMS_NOATTR. We could be more
flexible and permit authattrs optionally, but only permit minimal
content.
(*) VERIFYING_FIRMWARE_SIGNATURE
This requires that the SignedData content type be pkcs7-data and
requires authattrs. In future, this will require an attribute
holding the target firmware name in addition to the minimal set.
(*) VERIFYING_UNSPECIFIED_SIGNATURE
This requires that the SignedData content type be pkcs7-data but
allows either no authattrs or only permits the minimal set.
(*) VERIFYING_KEXEC_PE_SIGNATURE
This only supports the Authenticode SPC_INDIRECT_DATA content type
and requires at least an SpcSpOpusInfo authattr in addition to the
minimal set. It also permits an SPC_STATEMENT_TYPE authattr (and
an S/MIME capabilities authattr because the pesign program doesn't
remove these).
(*) VERIFYING_KEY_SIGNATURE
(*) VERIFYING_KEY_SELF_SIGNATURE
These are invalid in this context but are included for later use
when limiting the use of X.509 certs.
(4) The pkcs7_test key type is given a module parameter to select between
the above options for testing purposes. For example:
echo 1 >/sys/module/pkcs7_test_key/parameters/usage
keyctl padd pkcs7_test foo @s </tmp/stuff.pkcs7
will attempt to check the signature on stuff.pkcs7 as if it contains a
firmware blob (1 being VERIFYING_FIRMWARE_SIGNATURE).
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>
Extract the function that drives the PKCS#7 signature verification given a
data blob and a PKCS#7 blob out from the module signing code and lump it with
the system keyring code as it's generic. This makes it independent of module
config options and opens it to use by the firmware loader.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Kyle McMartin <kyle@kernel.org>
Bring back the functionality whereby an asymmetric key can be matched with a
partial match on one of its IDs.
Whilst we're at it, allow for the possibility of having an increased number of
IDs.
Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Implement the first step in using binary key IDs for asymmetric keys rather
than hex string keys.
The previously added match data preparsing will be able to convert hex
criterion strings into binary which can then be compared more rapidly.
Further, we actually want more then one ID string per public key. The problem
is that X.509 certs refer to other X.509 certs by matching Issuer + AuthKeyId
to Subject + SubjKeyId, but PKCS#7 messages match against X.509 Issuer +
SerialNumber.
This patch just provides facilities for a later patch to make use of.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
A previous patch added a ->match_preparse() method to the key type. This is
allowed to override the function called by the iteration algorithm.
Therefore, we can just set a default that simply checks for an exact match of
the key description with the original criterion data and allow match_preparse
to override it as needed.
The key_type::match op is then redundant and can be removed, as can the
user_match() function.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
