tls: zero the crypto information from tls_context before freeing

This contains key material in crypto_send_aes_gcm_128 and
crypto_recv_aes_gcm_128.

Introduce union tls_crypto_context, and replace the two identical
unions directly embedded in struct tls_context with it. We can then
use this union to clean up the memory in the new tls_ctx_free()
function.

Fixes: 3c4d7559159b ("tls: kernel TLS support")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tls.h b/include/net/tls.h
index d5c683e..0a769cf 100644 (file)
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -171,15 +171,14 @@ struct cipher_context {
        char *rec_seq;
 };
 
+union tls_crypto_context {
+       struct tls_crypto_info info;
+       struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
+};
+
 struct tls_context {
-       union {
-               struct tls_crypto_info crypto_send;
-               struct tls12_crypto_info_aes_gcm_128 crypto_send_aes_gcm_128;
-       };
-       union {
-               struct tls_crypto_info crypto_recv;
-               struct tls12_crypto_info_aes_gcm_128 crypto_recv_aes_gcm_128;
-       };
+       union tls_crypto_context crypto_send;
+       union tls_crypto_context crypto_recv;
 
        struct list_head list;
        struct net_device *netdev;
@@ -367,8 +366,8 @@ static inline void tls_fill_prepend(struct tls_context *ctx,
         * size KTLS_DTLS_HEADER_SIZE + KTLS_DTLS_NONCE_EXPLICIT_SIZE
         */
        buf[0] = record_type;
-       buf[1] = TLS_VERSION_MINOR(ctx->crypto_send.version);
-       buf[2] = TLS_VERSION_MAJOR(ctx->crypto_send.version);
+       buf[1] = TLS_VERSION_MINOR(ctx->crypto_send.info.version);
+       buf[2] = TLS_VERSION_MAJOR(ctx->crypto_send.info.version);
        /* we can use IV for nonce explicit according to spec */
        buf[3] = pkt_len >> 8;
        buf[4] = pkt_len & 0xFF;

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 292742e..961b07d 100644 (file)
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -686,7 +686,7 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
                goto free_marker_record;
        }
 
-       crypto_info = &ctx->crypto_send;
+       crypto_info = &ctx->crypto_send.info;
        switch (crypto_info->cipher_type) {
        case TLS_CIPHER_AES_GCM_128:
                nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
@@ -780,7 +780,7 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
 
        ctx->priv_ctx_tx = offload_ctx;
        rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_TX,
-                                            &ctx->crypto_send,
+                                            &ctx->crypto_send.info,
                                             tcp_sk(sk)->write_seq);
        if (rc)
                goto release_netdev;
@@ -862,7 +862,7 @@ int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx)
                goto release_ctx;
 
        rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_RX,
-                                            &ctx->crypto_recv,
+                                            &ctx->crypto_recv.info,
                                             tcp_sk(sk)->copied_seq);
        if (rc) {
                pr_err_ratelimited("%s: The netdev has refused to offload this socket\n",

diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
index 6102169..450a6db 100644 (file)
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -320,7 +320,7 @@ static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx,
                goto free_req;
 
        iv = buf;
-       memcpy(iv, tls_ctx->crypto_send_aes_gcm_128.salt,
+       memcpy(iv, tls_ctx->crypto_send.aes_gcm_128.salt,
               TLS_CIPHER_AES_GCM_128_SALT_SIZE);
        aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE +
              TLS_CIPHER_AES_GCM_128_IV_SIZE;

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 180b664..737b386 100644 (file)
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -241,6 +241,16 @@ static void tls_write_space(struct sock *sk)
        ctx->sk_write_space(sk);
 }
 
+static void tls_ctx_free(struct tls_context *ctx)
+{
+       if (!ctx)
+               return;
+
+       memzero_explicit(&ctx->crypto_send, sizeof(ctx->crypto_send));
+       memzero_explicit(&ctx->crypto_recv, sizeof(ctx->crypto_recv));
+       kfree(ctx);
+}
+
 static void tls_sk_proto_close(struct sock *sk, long timeout)
 {
        struct tls_context *ctx = tls_get_ctx(sk);
@@ -294,7 +304,7 @@ static void tls_sk_proto_close(struct sock *sk, long timeout)
 #else
        {
 #endif
-               kfree(ctx);
+               tls_ctx_free(ctx);
                ctx = NULL;
        }
 
@@ -305,7 +315,7 @@ skip_tx_cleanup:
         * for sk->sk_prot->unhash [tls_hw_unhash]
         */
        if (free_ctx)
-               kfree(ctx);
+               tls_ctx_free(ctx);
 }
 
 static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
@@ -330,7 +340,7 @@ static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
        }
 
        /* get user crypto info */
-       crypto_info = &ctx->crypto_send;
+       crypto_info = &ctx->crypto_send.info;
 
        if (!TLS_CRYPTO_INFO_READY(crypto_info)) {
                rc = -EBUSY;
@@ -417,9 +427,9 @@ static int do_tls_setsockopt_conf(struct sock *sk, char __user *optval,
        }
 
        if (tx)
-               crypto_info = &ctx->crypto_send;
+               crypto_info = &ctx->crypto_send.info;
        else
-               crypto_info = &ctx->crypto_recv;
+               crypto_info = &ctx->crypto_recv.info;
 
        /* Currently we don't support set crypto info more than one time */
        if (TLS_CRYPTO_INFO_READY(crypto_info)) {

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index f29b7c4..9e91848 100644 (file)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1055,8 +1055,8 @@ static int tls_read_size(struct strparser *strp, struct sk_buff *skb)
                goto read_failure;
        }
 
-       if (header[1] != TLS_VERSION_MINOR(tls_ctx->crypto_recv.version) ||
-           header[2] != TLS_VERSION_MAJOR(tls_ctx->crypto_recv.version)) {
+       if (header[1] != TLS_VERSION_MINOR(tls_ctx->crypto_recv.info.version) ||
+           header[2] != TLS_VERSION_MAJOR(tls_ctx->crypto_recv.info.version)) {
                ret = -EINVAL;
                goto read_failure;
        }
@@ -1180,12 +1180,12 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 
        if (tx) {
                crypto_init_wait(&sw_ctx_tx->async_wait);
-               crypto_info = &ctx->crypto_send;
+               crypto_info = &ctx->crypto_send.info;
                cctx = &ctx->tx;
                aead = &sw_ctx_tx->aead_send;
        } else {
                crypto_init_wait(&sw_ctx_rx->async_wait);
-               crypto_info = &ctx->crypto_recv;
+               crypto_info = &ctx->crypto_recv.info;
                cctx = &ctx->rx;
                aead = &sw_ctx_rx->aead_recv;
        }