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    Subject[PATCH 4.10 12/62] net/packet: fix overflow in check for tp_frame_nr
    Date
    4.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Andrey Konovalov <andreyknvl@google.com>


    [ Upstream commit 8f8d28e4d6d815a391285e121c3a53a0b6cb9e7b ]

    When calculating rb->frames_per_block * req->tp_block_nr the result
    can overflow.

    Add a check that tp_block_size * tp_block_nr <= UINT_MAX.

    Since frames_per_block <= tp_block_size, the expression would
    never overflow.

    Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
    Acked-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/packet/af_packet.c | 2 ++
    1 file changed, 2 insertions(+)

    --- a/net/packet/af_packet.c
    +++ b/net/packet/af_packet.c
    @@ -4189,6 +4189,8 @@ static int packet_set_ring(struct sock *
    rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
    if (unlikely(rb->frames_per_block == 0))
    goto out;
    + if (unlikely(req->tp_block_size > UINT_MAX / req->tp_block_nr))
    + goto out;
    if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
    req->tp_frame_nr))
    goto out;

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