ima: differentiate appraise status only for hook specific rules

Different hooks can require different methods for appraising a
file's integrity.  As a result, an integrity appraisal status is
cached on a per hook basis.

Only a hook specific rule, requires the inode to be re-appraised.
This patch eliminates unnecessary appraisals.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
This commit is contained in:
Mimi Zohar 2012-12-05 15:14:38 -05:00
parent d79d72e024
commit 5a73fcfa88
2 changed files with 12 additions and 6 deletions

View File

@ -146,7 +146,7 @@ static int process_measurement(struct file *file, const char *filename,
struct integrity_iint_cache *iint;
char *pathbuf = NULL;
const char *pathname = NULL;
int rc = -ENOMEM, action, must_appraise;
int rc = -ENOMEM, action, must_appraise, _func;
if (!ima_initialized || !S_ISREG(inode->i_mode))
return 0;
@ -161,6 +161,9 @@ static int process_measurement(struct file *file, const char *filename,
must_appraise = action & IMA_APPRAISE;
/* Is the appraise rule hook specific? */
_func = (action & IMA_FILE_APPRAISE) ? FILE_CHECK : function;
mutex_lock(&inode->i_mutex);
iint = integrity_inode_get(inode);
@ -178,7 +181,7 @@ static int process_measurement(struct file *file, const char *filename,
/* Nothing to do, just return existing appraised status */
if (!action) {
if (must_appraise)
rc = ima_get_cache_status(iint, function);
rc = ima_get_cache_status(iint, _func);
goto out_digsig;
}
@ -195,7 +198,7 @@ static int process_measurement(struct file *file, const char *filename,
if (action & IMA_MEASURE)
ima_store_measurement(iint, file, pathname);
if (action & IMA_APPRAISE_SUBMASK)
rc = ima_appraise_measurement(function, iint, file, pathname);
rc = ima_appraise_measurement(_func, iint, file, pathname);
if (action & IMA_AUDIT)
ima_audit_measurement(iint, pathname);
kfree(pathbuf);

View File

@ -220,10 +220,13 @@ retry:
/*
* In addition to knowing that we need to appraise the file in general,
* we need to differentiate between calling hooks.
* we need to differentiate between calling hooks, for hook specific rules.
*/
static int get_subaction(int func)
static int get_subaction(struct ima_rule_entry *rule, int func)
{
if (!(rule->flags & IMA_FUNC))
return IMA_FILE_APPRAISE;
switch(func) {
case MMAP_CHECK:
return IMA_MMAP_APPRAISE;
@ -268,7 +271,7 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
action |= entry->action & IMA_DO_MASK;
if (entry->action & IMA_APPRAISE)
action |= get_subaction(func);
action |= get_subaction(entry, func);
if (entry->action & IMA_DO_MASK)
actmask &= ~(entry->action | entry->action << 1);