ima: fix invalid memory reference

commit 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da upstream.

Don't free a valid measurement entry on TPM PCR extend failure.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 5 deletions

diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index e1a5062b1f6..55a6271bce7 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -23,6 +23,8 @@
 #include <linux/slab.h>
 #include "ima.h"
 
+#define AUDIT_CAUSE_LEN_MAX 32
+
 LIST_HEAD(ima_measurements);    /* list of all measurements */
 
 /* key: inode (before secure-hashing a file) */
@@ -94,7 +96,8 @@ static int ima_pcr_extend(const u8 *hash)
 
         result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash);
         if (result != 0)
-                pr_err("IMA: Error Communicating to TPM chip\n");
+                pr_err("IMA: Error Communicating to TPM chip, result: %d\n",
+                       result);
         return result;
 }
 
@@ -106,8 +109,9 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
 {
         u8 digest[IMA_DIGEST_SIZE];
         const char *audit_cause = "hash_added";
+        char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
         int audit_info = 1;
-        int result = 0;
+        int result = 0, tpmresult = 0;
 
         mutex_lock(&ima_extend_list_mutex);
         if (!violation) {
@@ -129,9 +133,11 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
         if (violation)          /* invalidate pcr */
                 memset(digest, 0xff, sizeof digest);
 
-        result = ima_pcr_extend(digest);
-        if (result != 0) {
-                audit_cause = "TPM error";
+        tpmresult = ima_pcr_extend(digest);
+        if (tpmresult != 0) {
+                snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
+                         tpmresult);
+                audit_cause = tpm_audit_cause;
                 audit_info = 0;
         }
 out: