crypto: asym_tpm: correct zero out potential secrets

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>

diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
index 378b18b9bc342a5aa9afb4efb8cf180f0a1edd76..84a5d6af9609e9a4f64ddeb0a2793998e1b83bcc 100644 (file)
--- a/crypto/asymmetric_keys/asym_tpm.c
+++ b/crypto/asymmetric_keys/asym_tpm.c
@@ -354,7 +354,7 @@ static uint32_t derive_pub_key(const void *pub_key, uint32_t len, uint8_t *buf)
        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;
 }