Re: [PATCH stable 5.10] net/tls: Fix authentication failure in CCM mode

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Dec 06, 2021 at 05:35:36PM +0800, Tianjia Zhang wrote:
> commit 5961060692f8b17cd2080620a3d27b95d2ae05ca upstream.
> 
> When the TLS cipher suite uses CCM mode, including AES CCM and
> SM4 CCM, the first byte of the B0 block is flags, and the real
> IV starts from the second byte. The XOR operation of the IV and
> rec_seq should be skip this byte, that is, add the iv_offset.
> 
> Fixes: f295b3ae9f59 ("net/tls: Add support of AES128-CCM based ciphers")
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> Cc: Vakul Garg <vakul.garg@nxp.com>
> Cc: stable@vger.kernel.org # v5.2+
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  net/tls/tls_sw.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index 122d5daed8b6..8cd011ea9fbb 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -515,7 +515,7 @@ static int tls_do_encryption(struct sock *sk,
>  	memcpy(&rec->iv_data[iv_offset], tls_ctx->tx.iv,
>  	       prot->iv_size + prot->salt_size);
>  
> -	xor_iv_with_seq(prot->version, rec->iv_data, tls_ctx->tx.rec_seq);
> +	xor_iv_with_seq(prot->version, rec->iv_data + iv_offset, tls_ctx->tx.rec_seq);
>  
>  	sge->offset += prot->prepend_size;
>  	sge->length -= prot->prepend_size;
> @@ -1487,7 +1487,7 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
>  	else
>  		memcpy(iv + iv_offset, tls_ctx->rx.iv, prot->salt_size);
>  
> -	xor_iv_with_seq(prot->version, iv, tls_ctx->rx.rec_seq);
> +	xor_iv_with_seq(prot->version, iv + iv_offset, tls_ctx->rx.rec_seq);
>  
>  	/* Prepare AAD */
>  	tls_make_aad(aad, rxm->full_len - prot->overhead_size +
> -- 
> 2.19.1.3.ge56e4f7
> 

Both backports now queued up, thanks.

greg k-h