From: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org,
Mimi Zohar <zohar@linux.ibm.com>,
Eric Biggers <ebiggers@kernel.org>
Subject: [PATCH 4/4] ima: support fs-verity file digest based signatures
Date: Mon, 29 Nov 2021 12:00:57 -0500 [thread overview]
Message-ID: <20211129170057.243127-5-zohar@linux.ibm.com> (raw)
In-Reply-To: <20211129170057.243127-1-zohar@linux.ibm.com>
Instead of calculating a file hash and verifying the signature stored
in the security.ima xattr against the calculated file hash, verify the
signature of the fs-verity's file digest. The fs-verity file digest is
a hash that includes the Merkle tree root hash.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
security/integrity/ima/ima_api.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 179c7f0364c2..ee1701f8c0f3 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -16,6 +16,7 @@
#include <linux/xattr.h>
#include <linux/evm.h>
#include <linux/iversion.h>
+#include <linux/fsverity.h>
#include "ima.h"
@@ -205,6 +206,23 @@ int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode,
allowed_algos);
}
+static int ima_collect_verity_measurement(struct integrity_iint_cache *iint,
+ struct ima_digest_data *hash)
+{
+ u8 verity_digest[FS_VERITY_MAX_DIGEST_SIZE];
+ enum hash_algo verity_alg;
+ int rc;
+
+ rc = fsverity_measure(iint->inode, verity_digest, &verity_alg);
+ if (rc)
+ return -EINVAL;
+ if (hash->algo != verity_alg)
+ return -EINVAL;
+ hash->length = hash_digest_size[verity_alg];
+ memcpy(hash->digest, verity_digest, hash->length);
+ return 0;
+}
+
/*
* ima_collect_measurement - collect file measurement
*
@@ -256,6 +274,8 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
if (buf)
result = ima_calc_buffer_hash(buf, size, &hash.hdr);
+ else if (veritysig)
+ result = ima_collect_verity_measurement(iint, &hash.hdr);
else
result = ima_calc_file_hash(file, &hash.hdr);
--
2.27.0
next prev parent reply other threads:[~2021-11-29 17:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 17:00 [PATCH 0/4] ima: support fs-verity signatures stored as Mimi Zohar
2021-11-29 17:00 ` [PATCH 1/4] fs-verity: define a function to return the integrity protected file digest Mimi Zohar
2021-11-29 23:16 ` kernel test robot
2021-11-29 23:36 ` kernel test robot
2021-11-30 2:19 ` Eric Biggers
2021-11-30 5:33 ` Lakshmi Ramasubramanian
2021-11-30 6:30 ` Eric Biggers
2021-11-29 17:00 ` [PATCH 2/4] ima: define a new signature type named IMA_VERITY_DIGSIG Mimi Zohar
2021-11-30 2:33 ` Eric Biggers
2021-11-30 18:14 ` Mimi Zohar
2021-12-02 16:25 ` Mimi Zohar
2021-12-02 21:17 ` Eric Biggers
2021-12-02 21:56 ` Mimi Zohar
2021-11-29 17:00 ` [PATCH 3/4] ima: limit including fs-verity's file digest in measurement list Mimi Zohar
2021-11-30 2:35 ` Eric Biggers
2021-11-30 13:15 ` Mimi Zohar
2021-11-30 5:46 ` Lakshmi Ramasubramanian
2021-11-29 17:00 ` Mimi Zohar [this message]
2021-11-30 5:56 ` [PATCH 4/4] ima: support fs-verity file digest based signatures Lakshmi Ramasubramanian
2021-11-30 13:36 ` Mimi Zohar
2021-11-30 2:36 ` [PATCH 0/4] ima: support fs-verity signatures stored as Eric Biggers
2021-11-30 12:56 ` Mimi Zohar
2021-11-30 22:49 ` Mimi Zohar
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