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Commit b16520f7 authored by Kees Cook's avatar Kees Cook Committed by David S. Miller
Browse files

net/tls: Remove VLA usage 

In the quest to remove VLAs from the kernel[1], this replaces the VLA
size with the only possible size used in the code, and adds a mechanism
to double-check future IV sizes.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarDave Watson <davejwatson@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 08ea556e

net/tls/tls_sw.c

+9 −1
Original line number Diff line number Diff line
@@ -41,6 +41,8 @@ 
#include <net/strparser.h>

#include <net/tls.h>



#define MAX_IV_SIZE	TLS_CIPHER_AES_GCM_128_IV_SIZE



static int tls_do_decryption(struct sock *sk,

			     struct scatterlist *sgin,

			     struct scatterlist *sgout,
@@ -673,7 +675,7 @@ static int decrypt_skb(struct sock *sk, struct sk_buff *skb, 
{

	struct tls_context *tls_ctx = tls_get_ctx(sk);

	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);

	char iv[TLS_CIPHER_AES_GCM_128_SALT_SIZE + tls_ctx->rx.iv_size];

	char iv[TLS_CIPHER_AES_GCM_128_SALT_SIZE + MAX_IV_SIZE];

	struct scatterlist sgin_arr[MAX_SKB_FRAGS + 2];

	struct scatterlist *sgin = &sgin_arr[0];

	struct strp_msg *rxm = strp_msg(skb);
@@ -1094,6 +1096,12 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx) 
		goto free_priv;

	}



	/* Sanity-check the IV size for stack allocations. */

	if (iv_size > MAX_IV_SIZE) {

		rc = -EINVAL;

		goto free_priv;

	}



	cctx->prepend_size = TLS_HEADER_SIZE + nonce_size;

	cctx->tag_size = tag_size;

	cctx->overhead_size = cctx->prepend_size + cctx->tag_size;