linux/include/crypto/public_key.h

124 lines
3.5 KiB

keys: X.509 public key issuer lookup without AKID There are non-root X.509 v3 certificates in use out there that contain no Authority Key Identifier extension (RFC5280 section 4.2.1.1). For trust verification purposes the kernel asymmetric key type keeps two struct asymmetric_key_id instances that the key can be looked up by, and another two to look up the key's issuer. The x509 public key type and the PKCS7 type generate them from the SKID and AKID extensions in the certificate. In effect current code has no way to look up the issuer certificate for verification without the AKID. To remedy this, add a third asymmetric_key_id blob to the arrays in both asymmetric_key_id's (for certficate subject) and in the public_keys_signature's auth_ids (for issuer lookup), using just raw subject and issuer DNs from the certificate. Adapt asymmetric_key_ids() and its callers to use the third ID for lookups when none of the other two are available. Attempt to keep the logic intact when they are, to minimise behaviour changes. Adapt the restrict functions' NULL-checks to include that ID too. Do not modify the lookup logic in pkcs7_verify.c, the AKID extensions are still required there. Internally use a new "dn:" prefix to the search specifier string generated for the key lookup in find_asymmetric_key(). This tells asymmetric_key_match_preparse to only match the data against the raw DN in the third ID and shouldn't conflict with search specifiers already in use. In effect implement what (2) in the struct asymmetric_key_id comment (include/keys/asymmetric-type.h) is probably talking about already, so do not modify that comment. It is also how "openssl verify" looks up issuer certificates without the AKID available. Lookups by the raw DN are unambiguous only provided that the CAs respect the condition in RFC5280 4.2.1.1 that the AKID may only be omitted if the CA uses a single signing key. The following is an example of two things that this change enables. A self-signed ceritficate is generated following the example from https://letsencrypt.org/docs/certificates-for-localhost/, and can be looked up by an identifier and verified against itself by linking to a restricted keyring -- both things not possible before due to the missing AKID extension: $ openssl req -x509 -out localhost.crt -outform DER -keyout localhost.key \ -newkey rsa:2048 -nodes -sha256 \ -subj '/CN=localhost' -extensions EXT -config <( \ echo -e "[dn]\nCN=localhost\n[req]\ndistinguished_name = dn\n[EXT]\n" \ "subjectAltName=DNS:localhost\nkeyUsage=digitalSignature\n" \ "extendedKeyUsage=serverAuth") $ keyring=`keyctl newring test @u` $ trusted=`keyctl padd asymmetric trusted $keyring < localhost.crt`; \ echo $trusted 39726322 $ keyctl search $keyring asymmetric dn:3112301006035504030c096c6f63616c686f7374 39726322 $ keyctl restrict_keyring $keyring asymmetric key_or_keyring:$trusted $ keyctl padd asymmetric verified $keyring < localhost.crt Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2021-11-09 16:16:49 +01:00
crypto: public_key: fix overflow during implicit conversion Hit kernel warning like this, it can be reproduced by verifying 256 bytes datafile by keyctl command, run script: RAWDATA=rawdata SIGDATA=sigdata modprobe pkcs8_key_parser rm -rf *.der *.pem *.pfx rm -rf $RAWDATA dd if=/dev/random of=$RAWDATA bs=256 count=1 openssl req -nodes -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem \ -subj "/C=CN/ST=GD/L=SZ/O=vihoo/OU=dev/CN=xx.com/emailAddress=yy@xx.com" KEY_ID=`openssl pkcs8 -in key.pem -topk8 -nocrypt -outform DER | keyctl \ padd asymmetric 123 @s` keyctl pkey_sign $KEY_ID 0 $RAWDATA enc=pkcs1 hash=sha1 > $SIGDATA keyctl pkey_verify $KEY_ID 0 $RAWDATA $SIGDATA enc=pkcs1 hash=sha1 Then the kernel reports: WARNING: CPU: 5 PID: 344556 at crypto/rsa-pkcs1pad.c:540 pkcs1pad_verify+0x160/0x190 ... Call Trace: public_key_verify_signature+0x282/0x380 ? software_key_query+0x12d/0x180 ? keyctl_pkey_params_get+0xd6/0x130 asymmetric_key_verify_signature+0x66/0x80 keyctl_pkey_verify+0xa5/0x100 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae The reason of this issue, in function 'asymmetric_key_verify_signature': '.digest_size(u8) = params->in_len(u32)' leads overflow of an u8 value, so use u32 instead of u8 for digest_size field. And reorder struct public_key_signature, it saves 8 bytes on a 64-bit machine. Cc: stable@vger.kernel.org Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2021-08-19 20:37:10 +08:00
pkcs7: Allow the signing algo to do whatever digestion it wants itself Allow the data to be verified in a PKCS#7 or CMS message to be passed directly to an asymmetric cipher algorithm (e.g. ML-DSA) if it wants to do whatever passes for hashing/digestion itself. The normal digestion of the data is then skipped as that would be ignored unless another signed info in the message has some other algorithm that needs it. The 'data to be verified' may be the content of the PKCS#7 message or it will be the authenticatedAttributes (signedAttrs if CMS), modified, if those are present. This is done by: (1) Make ->m and ->m_size point to the data to be verified rather than making public_key_verify_signature() access the data directly. This is so that keyctl(KEYCTL_PKEY_VERIFY) will still work. (2) Add a flag, ->algo_takes_data, to indicate that the verification algorithm wants to access the data to be verified directly rather than having it digested first. (3) If the PKCS#7 message has authenticatedAttributes (or CMS signedAttrs), then the digest contained therein will be validated as now, and the modified attrs blob will either be digested or assigned to ->m as appropriate. (4) If present, always copy and modify the authenticatedAttributes (or signedAttrs) then digest that in one go rather than calling the shash update twice (once for the tag and once for the rest). (5) For ML-DSA, point ->m to the TBSCertificate instead of digesting it and using the digest. Note that whilst ML-DSA does allow for an "external mu", CMS doesn't yet have that standardised. Signed-off-by: David Howells <dhowells@redhat.com> cc: Lukas Wunner <lukas@wunner.de> cc: Ignat Korchagin <ignat@cloudflare.com> cc: Stephan Mueller <smueller@chronox.de> cc: Eric Biggers <ebiggers@kernel.org> cc: Herbert Xu <herbert@gondor.apana.org.au> cc: keyrings@vger.kernel.org cc: linux-crypto@vger.kernel.org
2026-01-21 12:41:42 +00:00
KEYS: Move the point of trust determination to __key_link() 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>
2016-04-06 16:14:26 +01:00
KEYS: Move the point of trust determination to __key_link() 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>
2016-04-06 16:14:26 +01:00
KEYS: Move the point of trust determination to __key_link() 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>
2016-04-06 16:14:26 +01:00