netdev - Re: [PATCH net-next 0/2] sctp: unify sctp_make_op_error_fixed and sctp_make_op_error

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Message-ID: <20180501232822.GB5105@localhost.localdomain>
Date:   Tue, 1 May 2018 20:28:23 -0300
From:   Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, linux-sctp@...r.kernel.org,
        vyasevich@...il.com, nhorman@...driver.com, lucien.xin@...il.com
Subject: Re: [PATCH net-next 0/2] sctp: unify sctp_make_op_error_fixed and
 sctp_make_op_error_space

On Tue, May 01, 2018 at 12:13:53PM -0400, David Miller wrote:
> From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
> Date: Sun, 29 Apr 2018 12:56:30 -0300
>
> > These two variants are very close to each other and can be merged
> > to avoid code duplication. That's what this patchset does.
> >
> > First, we allow sctp_init_cause to return errors, which then allow us to
> > add sctp_make_op_error_limited that handles both situations.
>
> Series applied.

Thanks.

>
> But generally, there are a lot of smtp_init_cause() call sites with non-zero
> payload length that should start checking the return value now.

They are safe as is, because they follow the pattern:
- sctp_make_abort(...., somesize)
- sctp_init_cause(size)
where size is considered in somesize, so sctp_init_cause cannot fail
in there.

This new usage in sctp_make_op_error_limited is the only one where it
allocates a buffer without knowing how much data will actually be
pushed into it.

  Marcelo