diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index 6c7c52e..212c5d5 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -353,7 +353,9 @@
 	err = crypto_ahash_final(req);
 	if (err)
 		goto out_free_ahash;
-	memcpy(cksumout->data, checksumdata, cksumout->len);
+
+	memcpy(cksumout->data, checksumdata,
+	       min_t(int, cksumout->len, crypto_ahash_digestsize(tfm)));
 
 out_free_ahash:
 	ahash_request_free(req);
@@ -809,8 +811,7 @@
 	buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
 	buf->len += GSS_KRB5_TOK_HDR_LEN;
 
-	/* Do the HMAC */
-	hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
+	hmac.len = kctx->gk5e->cksumlength;
 	hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
 
 	/*
@@ -873,8 +874,7 @@
 	if (ret)
 		goto out_err;
 
-	/* Calculate our hmac over the plaintext data */
-	our_hmac_obj.len = sizeof(our_hmac);
+	our_hmac_obj.len = kctx->gk5e->cksumlength;
 	our_hmac_obj.data = our_hmac;
 	ret = gss_krb5_checksum(ahash, NULL, 0, &subbuf, 0, &our_hmac_obj);
 	if (ret)