ima: Directly free *entry in ima_alloc_init_template() if digests is NULL

To support multiple template digests, the static array entry->digest has
been replaced with a dynamically allocated array in commit aa724fe18a8a
("ima: Switch to dynamically allocated buffer for template digests"). The
array is allocated in ima_alloc_init_template() and if the returned pointer
is NULL, ima_free_template_entry() is called.

However, (*entry)->template_desc is not yet initialized while it is used by
ima_free_template_entry(). This patch fixes the issue by directly freeing
*entry without calling ima_free_template_entry().

Fixes: aa724fe18a8a ("ima: Switch to dynamically allocated buffer for template digests")
Reported-by: syzbot+223310b454ba6b75974e@syzkaller.appspotmail.com
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 78e0b0a7723ec9e79c5f17e6408f3d49b3136b22..bf22de8b7ce0728fe40922ceae49e31dca306fe0 100644 (file)
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -55,8 +55,9 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
        digests = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots,
                          sizeof(*digests), GFP_NOFS);
        if (!digests) {
-               result = -ENOMEM;
-               goto out;
+               kfree(*entry);
+               *entry = NULL;
+               return -ENOMEM;
        }
 
        (*entry)->digests = digests;