Re: [PATCH v4 1/3] KEYS: Expand key->{datalen,quotalen} to unsigned int

[sashiko-bot@kernel.org]

> In key_alloc() and key_payload_reserve(), key->quotalen and key->datalen
> can receive values larger than USHRT_MAX.
> 
> Example:
> 
>   keyctl new_session >/dev/null
>   owner=$(keyctl newring owner @s)
>   keeper=$(keyctl newring keeper @s)
> 
>   for ((i=0; i<16384; i++)); do
>       key=$(keyctl add user "k$i" x "$keeper")
>       keyctl link "$key" "$owner"
>   done
> 
>   awk -v uid="$(id -u):" '$1 == uid {print $NF}' /proc/key-users
>   keyctl clear "$owner"
>   awk -v uid="$(id -u):" '$1 == uid {print $NF}' /proc/key-users
> 
> Because key->datalen wraps around 65535, the quota refunded upon clearing
> is truncated, causing quota bytes to leak in /proc/key-users.
> 
> Change the types of key->datalen and key->quotalen from unsigned short to
> unsigned int so that they can carry the full payload length without
> truncation.
> 
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reviewed-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Sashiko has reviewed this patch and found no issues.

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