net/tls: Remove VLA usage on nonce

It looks like the prior VLA removal, commit b16520f7493d ("net/tls: Remove
VLA usage"), and a new VLA addition, commit c46234ebb4d1e ("tls: RX path
for ktls"), passed in the night. This removes the newly added VLA, which
happens to have its bounds based on the same max value.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 727433b..173d8b8 100644 (file)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -941,7 +941,7 @@ static int tls_read_size(struct strparser *strp, struct sk_buff *skb)
 {
        struct tls_context *tls_ctx = tls_get_ctx(strp->sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
-       char header[tls_ctx->rx.prepend_size];
+       char header[TLS_HEADER_SIZE + MAX_IV_SIZE];
        struct strp_msg *rxm = strp_msg(skb);
        size_t cipher_overhead;
        size_t data_len = 0;
@@ -951,6 +951,12 @@ static int tls_read_size(struct strparser *strp, struct sk_buff *skb)
        if (rxm->offset + tls_ctx->rx.prepend_size > skb->len)
                return 0;
 
+       /* Sanity-check size of on-stack buffer. */
+       if (WARN_ON(tls_ctx->rx.prepend_size > sizeof(header))) {
+               ret = -EINVAL;
+               goto read_failure;
+       }
+
        /* Linearize header to local buffer */
        ret = skb_copy_bits(skb, rxm->offset, header, tls_ctx->rx.prepend_size);
 
@@ -1108,7 +1114,7 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
        }
 
        /* Sanity-check the IV size for stack allocations. */
-       if (iv_size > MAX_IV_SIZE) {
+       if (iv_size > MAX_IV_SIZE || nonce_size > MAX_IV_SIZE) {
                rc = -EINVAL;
                goto free_priv;
        }