Re: [PATCH v3 08/12] ima: Shallow copy the args_p member of ima_rule_entry.lsm elements

The args_p member is a simple string that is allocated by
ima_rule_init(). Shallow copy it like other non-LSM references in
ima_rule_entry structs.

There are no longer any necessary error path cleanups to do in
ima_lsm_copy_rule().

Signed-off-by: Tyler Hicks <redacted>
---

* v3
  - No change
* v2
  - Adjusted context to account for ima_lsm_copy_rule() directly calling
    ima_lsm_free_rule() and the lack of explicit reference ownership
    transfers
  - Added comment to ima_lsm_copy_rule() to document the args_p
    reference ownership transfer

 security/integrity/ima/ima_policy.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 9842e2e0bc6d..b02e1ffd10c9 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c

@@ -300,10 +300,13 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
                        continue;

                nentry->lsm[i].type = entry->lsm[i].type;
-               nentry->lsm[i].args_p = kstrdup(entry->lsm[i].args_p,
-                                               GFP_KERNEL);
-               if (!nentry->lsm[i].args_p)
-                       goto out_err;
+               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;

                security_filter_rule_init(nentry->lsm[i].type,
                                          Audit_equal,

@@ -314,11 +317,6 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
                                (char *)entry->lsm[i].args_p);