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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Ilil Blum Shem-Tov <ilil.blum.shem-tov@intel.com>
Subject: [PATCH 5.4 50/92] crypto: asym_tpm: correct zero out potential secrets
Date:   Mon, 11 Jan 2021 14:01:54 +0100
Message-Id: <20210111130041.550571666@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit f93274ef0fe972c120c96b3207f8fce376231a60 upstream.

The function derive_pub_key() should be calling memzero_explicit()
instead of memset() in case the complier decides to optimize away the
call to memset() because it "knows" no one is going to touch the memory
anymore.

Cc: stable <stable@vger.kernel.org>
Reported-by: Ilil Blum Shem-Tov <ilil.blum.shem-tov@intel.com>
Tested-by: Ilil Blum Shem-Tov <ilil.blum.shem-tov@intel.com>
Link: https://lore.kernel.org/r/X8ns4AfwjKudpyfe@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/asymmetric_keys/asym_tpm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/crypto/asymmetric_keys/asym_tpm.c
+++ b/crypto/asymmetric_keys/asym_tpm.c
@@ -370,7 +370,7 @@ static uint32_t derive_pub_key(const voi
 	memcpy(cur, e, sizeof(e));
 	cur += sizeof(e);
 	/* Zero parameters to satisfy set_pub_key ABI. */
-	memset(cur, 0, SETKEY_PARAMS_SIZE);
+	memzero_explicit(cur, SETKEY_PARAMS_SIZE);
 
 	return cur - buf;
 }