On 06/23/2017 07:32 PM, Julian Wiedmann wrote:
> From: Mateusz Jurczyk <mjurczyk@xxxxxxxxxx>
>
> Verify that the caller-provided sockaddr structure is large enough to
> contain the sa_family field, before accessing it in bind() and connect()
> handlers of the AF_IUCV socket. Since neither syscall enforces a minimum
> size of the corresponding memory region, very short sockaddrs (zero or
> one byte long) result in operating on uninitialized memory while
> referencing .sa_family.
Won't it make sense to generally check the minimum length for .sa_family at a
single point before fixing all called sites?
Regards,
Oliver
>
> Fixes: 52a82e23b9f2 ("af_iucv: Validate socket address length in iucv_sock_bind()")
> Signed-off-by: Mateusz Jurczyk <mjurczyk@xxxxxxxxxx>
> [jwi: removed unneeded null-check for addr]
> Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
> ---
> net/iucv/af_iucv.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
> index 05112094d76b..ac033e413bc5 100644
> --- a/net/iucv/af_iucv.c
> +++ b/net/iucv/af_iucv.c
> @@ -715,10 +715,8 @@ static int iucv_sock_bind(struct socket *sock, struct sockaddr *addr,
> char uid[9];
>
> /* Verify the input sockaddr */
> - if (!addr || addr->sa_family != AF_IUCV)
> - return -EINVAL;
> -
> - if (addr_len < sizeof(struct sockaddr_iucv))
> + if (addr_len < sizeof(struct sockaddr_iucv) ||
> + addr->sa_family != AF_IUCV)
> return -EINVAL;
>
> lock_sock(sk);
> @@ -862,7 +860,7 @@ static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr,
> struct iucv_sock *iucv = iucv_sk(sk);
> int err;
>
> - if (addr->sa_family != AF_IUCV || alen < sizeof(struct sockaddr_iucv))
> + if (alen < sizeof(struct sockaddr_iucv) || addr->sa_family != AF_IUCV)
> return -EINVAL;
>
> if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
>
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