tls: expand use of tls_cipher_desc in tls_set_device_offload

tls_set_device_offload is already getting iv and rec_seq sizes from
tls_cipher_desc. We can now also check if the cipher_type coming from
userspace is valid and can be offloaded.

We can also remove the runtime check on rec_seq, since we validate it
at compile time.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/8ab71b8eca856c7aaf981a45fe91ac649eb0e2e9.1692977948.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 98885d8..8c94c92 100644 (file)
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -1079,29 +1079,15 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
                goto release_netdev;
        }
 
-       switch (crypto_info->cipher_type) {
-       case TLS_CIPHER_AES_GCM_128:
-               iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv;
-               rec_seq =
-                ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq;
-               break;
-       case TLS_CIPHER_AES_GCM_256:
-               iv = ((struct tls12_crypto_info_aes_gcm_256 *)crypto_info)->iv;
-               rec_seq =
-                ((struct tls12_crypto_info_aes_gcm_256 *)crypto_info)->rec_seq;
-               break;
-       default:
-               rc = -EINVAL;
-               goto release_netdev;
-       }
        cipher_desc = get_cipher_desc(crypto_info->cipher_type);
-
-       /* Sanity-check the rec_seq_size for stack allocations */
-       if (cipher_desc->rec_seq > TLS_MAX_REC_SEQ_SIZE) {
+       if (!cipher_desc || !cipher_desc->offloadable) {
                rc = -EINVAL;
                goto release_netdev;
        }
 
+       iv = crypto_info_iv(crypto_info, cipher_desc);
+       rec_seq = crypto_info_rec_seq(crypto_info, cipher_desc);
+
        prot->version = crypto_info->version;
        prot->cipher_type = crypto_info->cipher_type;
        prot->prepend_size = TLS_HEADER_SIZE + cipher_desc->iv;