ACK: [PATCH 2/2] UBUNTU: SAUCE: irda: Only insert new objects into the global database via setsockopt

[Colin Ian King]

On 04/09/18 16:12, Tyler Hicks wrote:
> The irda_setsockopt() function conditionally allocates memory for a new
> self->ias_object or, in some cases, reuses the existing
> self->ias_object. Existing objects were incorrectly reinserted into the
> LM_IAS database which corrupted the doubly linked list used for the
> hashbin implementation of the LM_IAS database. When combined with a
> memory leak in irda_bind(), this issue could be leveraged to create a
> use-after-free vulnerability in the hashbin list. This patch fixes the
> issue by only inserting newly allocated objects into the database.
> 
> CVE-2018-6555
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
> Reviewed-by: Seth Arnold <seth.arnold at canonical.com>
> Reviewed-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>  net/irda/af_irda.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
> index 82e632b2c5a1..7cc9db38e1b6 100644
> --- a/net/irda/af_irda.c
> +++ b/net/irda/af_irda.c
> @@ -2027,7 +2027,11 @@ static int irda_setsockopt(struct socket *sock, int level, int optname,
>  			err = -EINVAL;
>  			goto out;
>  		}
> -		irias_insert_object(ias_obj);
> +
> +		/* Only insert newly allocated objects */
> +		if (free_ias)
> +			irias_insert_object(ias_obj);
> +
>  		kfree(ias_opt);
>  		break;
>  	case IRLMP_IAS_DEL:
> 

Makes sense.

Acked-by: Colin Ian King <colin.king at canonical.com>