From: Stefan Berger <stefanb@linux.ibm.com>
To: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-unionfs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, paul@paul-moore.com,
jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com,
roberto.sassu@huawei.com, amir73il@gmail.com, brauner@kernel.org,
miklos@szeredi.hu, Stefan Berger <stefanb@linux.ibm.com>
Subject: [PATCH v2 9/9] ima: Record i_version of real_inode for change detection
Date: Mon, 5 Feb 2024 13:25:06 -0500 [thread overview]
Message-ID: <20240205182506.3569743-10-stefanb@linux.ibm.com> (raw)
In-Reply-To: <20240205182506.3569743-1-stefanb@linux.ibm.com>
process_measurement() will try to detect file content changes for not-yet-
copied-up files on a stacked filesystem based on the i_version number of
the real inode: !inode_eq_iversion(real_inode, iint->version)
Therefore, take a snapshot of the i_version of the real file to be used
for i_version number-based file content change detection by IMA in
process_meassurements().
In this case vfs_getattr_nosec() cannot be used since it will return the
i_version number of the file on the overlay layer which will trigger more
iint resets in process_measurements() than necessary since this i_version
number represents different state than that of the real_inode (of a
not-yet-copied up file).
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
security/integrity/ima/ima_api.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 597ea0c4d72f..530888cc481e 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -14,6 +14,7 @@
#include <linux/xattr.h>
#include <linux/evm.h>
#include <linux/fsverity.h>
+#include <linux/iversion.h>
#include "ima.h"
@@ -250,7 +251,6 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
int result = 0;
int length;
void *tmpbuf;
- u64 i_version = 0;
/*
* Always collect the modsig, because IMA might have already collected
@@ -263,16 +263,6 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
if (iint->flags & IMA_COLLECTED)
goto out;
- /*
- * Detecting file change is based on i_version. On filesystems
- * which do not support i_version, support was originally limited
- * to an initial measurement/appraisal/audit, but was modified to
- * assume the file changed.
- */
- result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE,
- AT_STATX_SYNC_AS_STAT);
- if (!result && (stat.result_mask & STATX_CHANGE_COOKIE))
- i_version = stat.change_cookie;
hash.hdr.algo = algo;
hash.hdr.length = hash_digest_size[algo];
@@ -302,10 +292,22 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
iint->ima_hash = tmpbuf;
memcpy(iint->ima_hash, &hash, length);
- iint->version = i_version;
- if (real_inode != inode) {
+ if (real_inode == inode) {
+ /*
+ * Detecting file change is based on i_version. On filesystems
+ * which do not support i_version, support was originally limited
+ * to an initial measurement/appraisal/audit, but was modified to
+ * assume the file changed.
+ */
+ result = vfs_getattr_nosec(&file->f_path, &stat,
+ STATX_CHANGE_COOKIE,
+ AT_STATX_SYNC_AS_STAT);
+ if (!result && (stat.result_mask & STATX_CHANGE_COOKIE))
+ iint->version = stat.change_cookie;
+ } else {
iint->real_ino = real_inode->i_ino;
iint->real_dev = real_inode->i_sb->s_dev;
+ iint->version = inode_query_iversion(real_inode);
}
/* Possibly temporary failure due to type of read (eg. O_DIRECT) */
--
2.43.0
next prev parent reply other threads:[~2024-02-05 18:25 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 18:24 [PATCH v2 0/9] evm: Support signatures on stacked filesystem Stefan Berger
2024-02-05 18:24 ` [PATCH v2 1/9] ima: Rename backing_inode to real_inode Stefan Berger
2024-02-06 15:23 ` Amir Goldstein
2024-02-05 18:24 ` [PATCH v2 2/9] security: allow finer granularity in permitting copy-up of security xattrs Stefan Berger
2024-02-06 15:12 ` Amir Goldstein
2024-02-20 22:57 ` Paul Moore
2024-02-05 18:25 ` [PATCH v2 3/9] evm: Implement per signature type decision in security_inode_copy_up_xattr Stefan Berger
2024-02-05 18:25 ` [PATCH v2 4/9] ima: Reset EVM status upon detecting changes to the real file Stefan Berger
2024-02-06 12:38 ` kernel test robot
2024-02-06 15:44 ` Amir Goldstein
2024-02-07 5:04 ` kernel test robot
2024-02-05 18:25 ` [PATCH v2 5/9] evm: Use the inode holding the metadata to calculate metadata hash Stefan Berger
2024-02-06 15:33 ` Amir Goldstein
2024-02-06 18:22 ` kernel test robot
2024-02-05 18:25 ` [PATCH v2 6/9] evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509 Stefan Berger
2024-02-05 18:25 ` [PATCH v2 7/9] fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED Stefan Berger
2024-02-06 15:11 ` Amir Goldstein
2024-02-05 18:25 ` [PATCH v2 8/9] evm: Rename is_unsupported_fs to is_unsupported_hmac_fs Stefan Berger
2024-02-05 18:25 ` Stefan Berger [this message]
2024-02-06 15:23 ` [PATCH v2 9/9] ima: Record i_version of real_inode for change detection Amir Goldstein
2024-02-06 15:54 ` Jeff Layton
2024-02-13 23:14 ` Stefan Berger
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