[PATCH v4 09/13] security: keys: trusted: always clear the hmac_sha1_ctx before returning

[Thomas Huth <thuth@redhat.com>]

Clear the hmac_sha1_ctx structure via __cleanup(hmac_sha1_zeroize_ctx)
to make sure that the function does not leak sensitive data on the stack
when returning without calling hmac_sha1_final().

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 security/keys/trusted-keys/trusted_tpm1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index bf0bf7f369705..e5a904b5c1946 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -101,7 +101,7 @@ static inline void dump_tpm_buf(unsigned char *buf)
 static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
 		       unsigned int keylen, ...)
 {
-	struct hmac_sha1_ctx hmac_ctx;
+	struct hmac_sha1_ctx hmac_ctx __cleanup(hmac_sha1_zeroize_ctx);
 	va_list argp;
 	unsigned int dlen;
 	unsigned char *data;
-- 
2.55.0