From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: linux-security-module@vger.kernel.org, keyrings@vger.kernel.org,
linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
David Howells <dhowells@redhat.com>,
David Woodhouse <dwmw2@infradead.org>,
Jessica Yu <jeyu@kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
"AKASHI, Takahiro" <takahiro.akashi@linaro.org>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>
Subject: [PATCH v7 06/14] integrity: Introduce asymmetric_sig_has_known_key()
Date: Tue, 22 May 2018 21:12:45 -0300 [thread overview]
Message-ID: <20180523001253.15247-7-bauerman@linux.ibm.com> (raw)
In-Reply-To: <20180523001253.15247-1-bauerman@linux.ibm.com>
IMA will only look for a modsig if the xattr sig references a key which is
not in the expected kernel keyring. To that end, introduce
asymmetric_sig_has_known_key().
The logic of extracting the key used in the xattr sig is factored out from
asymmetric_verify() so that it can be used by the new function.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
security/integrity/digsig_asymmetric.c | 44 +++++++++++++++++++++++++---------
security/integrity/integrity.h | 8 +++++++
2 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
index ab6a029062a1..241647970c19 100644
--- a/security/integrity/digsig_asymmetric.c
+++ b/security/integrity/digsig_asymmetric.c
@@ -79,26 +79,48 @@ static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid)
return key;
}
-int asymmetric_verify(struct key *keyring, const char *sig,
- int siglen, const char *data, int datalen)
+static struct key *asymmetric_key_from_sig(struct key *keyring, const char *sig,
+ int siglen)
{
- struct public_key_signature pks;
- struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
- struct key *key;
- int ret = -ENOMEM;
+ const struct signature_v2_hdr *hdr = (struct signature_v2_hdr *) sig;
if (siglen <= sizeof(*hdr))
- return -EBADMSG;
+ return ERR_PTR(-EBADMSG);
siglen -= sizeof(*hdr);
if (siglen != be16_to_cpu(hdr->sig_size))
- return -EBADMSG;
+ return ERR_PTR(-EBADMSG);
if (hdr->hash_algo >= HASH_ALGO__LAST)
- return -ENOPKG;
+ return ERR_PTR(-ENOPKG);
+
+ return request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid));
+}
+
+bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig,
+ int siglen)
+{
+ struct key *key;
+
+ key = asymmetric_key_from_sig(keyring, sig, siglen);
+ if (IS_ERR_OR_NULL(key))
+ return false;
+
+ key_put(key);
+
+ return true;
+}
+
+int asymmetric_verify(struct key *keyring, const char *sig,
+ int siglen, const char *data, int datalen)
+{
+ struct public_key_signature pks;
+ struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
+ struct key *key;
+ int ret = -ENOMEM;
- key = request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid));
+ key = asymmetric_key_from_sig(keyring, sig, siglen);
if (IS_ERR(key))
return PTR_ERR(key);
@@ -109,7 +131,7 @@ int asymmetric_verify(struct key *keyring, const char *sig,
pks.digest = (u8 *)data;
pks.digest_size = datalen;
pks.s = hdr->sig;
- pks.s_size = siglen;
+ pks.s_size = siglen - sizeof(*hdr);
ret = verify_signature(key, &pks);
key_put(key);
pr_debug("%s() = %d\n", __func__, ret);
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index d4f676906442..7f80c3e44d51 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -181,12 +181,20 @@ static inline int integrity_init_keyring(const unsigned int id)
#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen);
+bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig,
+ int siglen);
#else
static inline int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen)
{
return -EOPNOTSUPP;
}
+
+static inline bool asymmetric_sig_has_known_key(struct key *keyring,
+ const char *sig, int siglen)
+{
+ return false;
+}
#endif
#ifdef CONFIG_IMA_LOAD_X509
next prev parent reply other threads:[~2018-05-23 0:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-23 0:12 [PATCH v7 00/14] Appended signatures support for IMA appraisal Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 01/14] MODSIGN: Export module signature definitions Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 02/14] PKCS#7: Refactor verify_pkcs7_signature() and add pkcs7_get_message_sig() Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 03/14] PKCS#7: Introduce pkcs7_get_digest() Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 04/14] integrity: Introduce struct evm_xattr Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 05/14] integrity: Introduce integrity_keyring_from_id() Thiago Jung Bauermann
2018-05-23 0:12 ` Thiago Jung Bauermann [this message]
2018-05-23 0:12 ` [PATCH v7 07/14] integrity: Select CONFIG_KEYS instead of depending on it Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 08/14] ima: Introduce is_signed() Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 09/14] ima: Export func_tokens Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 10/14] ima: Add modsig appraise_type option for module-style appended signatures Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 11/14] ima: Implement support " Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 12/14] ima: Add new "d-sig" template field Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 13/14] ima: Write modsig to the measurement list Thiago Jung Bauermann
2018-05-23 0:12 ` [PATCH v7 14/14] ima: Store the measurement again when appraising a modsig Thiago Jung Bauermann
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