path: root/security
diff options
authorDmitry Kasatkin <d.kasatkin@samsung.com>2014-03-27 10:29:28 +0200
committerMimi Zohar <zohar@linux.vnet.ibm.com>2014-06-12 17:58:07 -0400
commit14503eb99414ceffe348b82982d5770b745f6626 (patch)
treef36a32c4d6e88b1668308495bbb2b37816360a40 /security
parentb882fae2d3a832fdcdc194c9f358390b1efca8e7 (diff)
ima: check inode integrity cache in violation check
When IMA did not support ima-appraisal, existance of the S_IMA flag clearly indicated that the file was measured. With IMA appraisal S_IMA flag indicates that file was measured and/or appraised. Because of this, when measurement is not enabled by the policy, violations are still reported. To differentiate between measurement and appraisal policies this patch checks the inode integrity cache flags. The IMA_MEASURED flag indicates whether the file was actually measured, while the IMA_MEASURE flag indicates whether the file should be measured. Unfortunately, the IMA_MEASURED flag is reset to indicate the file needs to be re-measured. Thus, this patch checks the IMA_MEASURE flag. This patch limits the false positive violation reports, but does not fix it entirely. The IMA_MEASURE/IMA_MEASURED flags are indications that, at some point in time, the file opened for read was in policy, but might not be in policy now (eg. different uid). Other changes would be needed to further limit false positive violation reports. Changelog: - expanded patch description based on conversation with Roberto (Mimi) Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Diffstat (limited to 'security')
1 files changed, 7 insertions, 2 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 7689c1e21f09..09baa335ebc7 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -91,8 +91,13 @@ static void ima_rdwr_violation_check(struct file *file)
mutex_lock(&inode->i_mutex); /* file metadata: permissions, xattr */
if (mode & FMODE_WRITE) {
- if (atomic_read(&inode->i_readcount) && IS_IMA(inode))
- send_tomtou = true;
+ if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
+ struct integrity_iint_cache *iint;
+ iint = integrity_iint_find(inode);
+ /* IMA_MEASURE is set from reader side */
+ if (iint && (iint->flags & IMA_MEASURE))
+ send_tomtou = true;
+ }
} else {
if ((atomic_read(&inode->i_writecount) > 0) &&
ima_must_measure(inode, MAY_READ, FILE_CHECK))

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