From f2b1b66b7c3218fc27da12ce4652646ef789f70f Mon Sep 17 00:00:00 2001
From: Mimi Zohar <zohar@linux.ibm.com>
Date: Fri, 26 Aug 2022 14:10:43 -0400
Subject: [PATCH] Fix potential use after free in read_tpm_banks()

On failure to read TPM 2.0 bank PCRs 'errmsg' is not properly set to
NULL after being freed.  Fix potential use after free.

Fixes: 3472f9ba9c05 ("ima-evm-utils: read the PCRs for the requested TPM banks")
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 src/evmctl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/evmctl.c b/src/evmctl.c
index a30b7f3..b8ba339 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -2075,6 +2075,7 @@ static int read_tpm_banks(int num_banks, struct tpm_bank_info *bank)
 				log_debug("Failed to read %s PCRs: (%s)\n",
 					  bank[i].algo_name, errmsg);
 				free(errmsg);
+				errmsg = NULL;
 				bank[i].supported = 0;
 			}
 		}