linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Mimi Zohar <zohar@linux.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>,
	Jonathan Corbet <corbet@lwn.net>,
	"AKASHI, Takahiro" <takahiro.akashi@linaro.org>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>
Subject: [PATCH v11 04/13] integrity: Introduce struct evm_xattr
Date: Tue, 11 Jun 2019 03:28:08 -0300	[thread overview]
Message-ID: <20190611062817.18412-5-bauerman@linux.ibm.com> (raw)
In-Reply-To: <20190611062817.18412-1-bauerman@linux.ibm.com>

Even though struct evm_ima_xattr_data includes a fixed-size array to hold a
SHA1 digest, most of the code ignores the array and uses the struct to mean
"type indicator followed by data of unspecified size" and tracks the real
size of what the struct represents in a separate length variable.

The only exception to that is the EVM code, which correctly uses the
definition of struct evm_ima_xattr_data.

So make this explicit in the code by removing the length specification from
the array in struct evm_ima_xattr_data. Also, change the name of the
element from digest to data since in most places the array doesn't hold a
digest.

A separate struct evm_xattr is introduced, with the original definition of
evm_ima_xattr_data to be used in the places that actually expect that
definition, specifically the EVM HMAC code.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/evm/evm_main.c     | 8 ++++----
 security/integrity/ima/ima_appraise.c | 7 ++++---
 security/integrity/integrity.h        | 6 ++++++
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index b6d9f14bc234..588f22f1b5bd 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -169,7 +169,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
 	/* check value type */
 	switch (xattr_data->type) {
 	case EVM_XATTR_HMAC:
-		if (xattr_len != sizeof(struct evm_ima_xattr_data)) {
+		if (xattr_len != sizeof(struct evm_xattr)) {
 			evm_status = INTEGRITY_FAIL;
 			goto out;
 		}
@@ -179,7 +179,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
 				   xattr_value_len, &digest);
 		if (rc)
 			break;
-		rc = crypto_memneq(xattr_data->digest, digest.digest,
+		rc = crypto_memneq(xattr_data->data, digest.digest,
 				   SHA1_DIGEST_SIZE);
 		if (rc)
 			rc = -EINVAL;
@@ -523,7 +523,7 @@ int evm_inode_init_security(struct inode *inode,
 				 const struct xattr *lsm_xattr,
 				 struct xattr *evm_xattr)
 {
-	struct evm_ima_xattr_data *xattr_data;
+	struct evm_xattr *xattr_data;
 	int rc;
 
 	if (!evm_key_loaded() || !evm_protected_xattr(lsm_xattr->name))
@@ -533,7 +533,7 @@ int evm_inode_init_security(struct inode *inode,
 	if (!xattr_data)
 		return -ENOMEM;
 
-	xattr_data->type = EVM_XATTR_HMAC;
+	xattr_data->data.type = EVM_XATTR_HMAC;
 	rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest);
 	if (rc < 0)
 		goto out;
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 2f6536ab69e8..18bbe753421a 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -168,7 +168,8 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
 		return sig->hash_algo;
 		break;
 	case IMA_XATTR_DIGEST_NG:
-		ret = xattr_value->digest[0];
+		/* first byte contains algorithm id */
+		ret = xattr_value->data[0];
 		if (ret < HASH_ALGO__LAST)
 			return ret;
 		break;
@@ -176,7 +177,7 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
 		/* this is for backward compatibility */
 		if (xattr_len == 21) {
 			unsigned int zero = 0;
-			if (!memcmp(&xattr_value->digest[16], &zero, 4))
+			if (!memcmp(&xattr_value->data[16], &zero, 4))
 				return HASH_ALGO_MD5;
 			else
 				return HASH_ALGO_SHA1;
@@ -275,7 +276,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 			/* xattr length may be longer. md5 hash in previous
 			   version occupied 20 bytes in xattr, instead of 16
 			 */
-			rc = memcmp(&xattr_value->digest[hash_start],
+			rc = memcmp(&xattr_value->data[hash_start],
 				    iint->ima_hash->digest,
 				    iint->ima_hash->length);
 		else
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 7de59f44cba3..88a29f72a74f 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -79,6 +79,12 @@ enum evm_ima_xattr_type {
 
 struct evm_ima_xattr_data {
 	u8 type;
+	u8 data[];
+} __packed;
+
+/* Only used in the EVM HMAC code. */
+struct evm_xattr {
+	struct evm_ima_xattr_data data;
 	u8 digest[SHA1_DIGEST_SIZE];
 } __packed;
 


  parent reply	other threads:[~2019-06-11  6:29 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-11  6:28 [PATCH v11 00/13] Appended signatures support for IMA appraisal Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 01/13] MODSIGN: Export module signature definitions Thiago Jung Bauermann
2019-06-24 19:52   ` Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 02/13] PKCS#7: Refactor verify_pkcs7_signature() Thiago Jung Bauermann
2019-06-24 19:56   ` Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 03/13] PKCS#7: Introduce pkcs7_get_digest() Thiago Jung Bauermann
2019-06-11  6:28 ` Thiago Jung Bauermann [this message]
2019-06-11  6:28 ` [PATCH v11 05/13] integrity: Select CONFIG_KEYS instead of depending on it Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 06/13] ima: Use designated initializers for struct ima_event_data Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 07/13] ima: Add modsig appraise_type option for module-style appended signatures Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 08/13] ima: Factor xattr_verify() out of ima_appraise_measurement() Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 09/13] ima: Implement support for module-style appended signatures Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 10/13] ima: Collect modsig Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 11/13] ima: Define ima-modsig template Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 12/13] ima: Store the measurement again when appraising a modsig Thiago Jung Bauermann
2019-06-11  6:28 ` [PATCH v11 13/13] ima: Allow template= option for appraise rules as well Thiago Jung Bauermann

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190611062817.18412-5-bauerman@linux.ibm.com \
    --to=bauerman@linux.ibm.com \
    --cc=corbet@lwn.net \
    --cc=davem@davemloft.net \
    --cc=dhowells@redhat.com \
    --cc=dmitry.kasatkin@gmail.com \
    --cc=dwmw2@infradead.org \
    --cc=herbert@gondor.apana.org.au \
    --cc=jeyu@kernel.org \
    --cc=jmorris@namei.org \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=serge@hallyn.com \
    --cc=takahiro.akashi@linaro.org \
    --cc=zohar@linux.ibm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).