[PATCH 5.15 702/731] ima: Simplify ima_lsm_copy_rule

Greg Kroah-Hartman
2022-12-28T16:01:14Z

From: GUO Zihua <guozihua@huawei.com>

[ Upstream commit d57378d3aa4d864d9e590482602068af1b20c0c5 ]

Currently ima_lsm_copy_rule() set the arg_p field of the source rule to
NULL, so that the source rule could be freed afterward. It does not make
sense for this behavior to be inside a "copy" function. So move it
outside and let the caller handle this field.

ima_lsm_copy_rule() now produce a shallow copy of the original entry
including args_p field. Meaning only the lsm.rule and the rule itself
should be freed for the original rule. Thus, instead of calling
ima_lsm_free_rule() which frees lsm.rule as well as args_p field, free
the lsm.rule directly.

Signed-off-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/integrity/ima/ima_policy.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 844d69f6ac00..ed43d30682ff 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -391,12 +391,6 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)

nentry->lsm[i].type = entry->lsm[i].type;
nentry->lsm[i].args_p = entry->lsm[i].args_p;
- /*
- * Remove the reference from entry so that the associated
- * memory will not be freed during a later call to
- * ima_lsm_free_rule(entry).
- */
- entry->lsm[i].args_p = NULL;

ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
nentry->lsm[i].args_p,
@@ -410,6 +404,7 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)

static int ima_lsm_update_rule(struct ima_rule_entry *entry)
{
+ int i;
struct ima_rule_entry *nentry;

nentry = ima_lsm_copy_rule(entry);
@@ -424,7 +419,8 @@ static int ima_lsm_update_rule(struct ima_rule_entry *entry)
* references and the entry itself. All other memory refrences will now
* be owned by nentry.
*/
- ima_lsm_free_rule(entry);
+ for (i = 0; i < MAX_LSM_RULES; i++)
+ ima_filter_rule_free(entry->lsm[i].rule);
kfree(entry);

return 0;
--
2.35.1