From: Hyunwoo Kim <imv4bel@gmail.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, imv4bel@gmail.com
Subject: Re: [PATCH] efi/capsule-loader: Fix use-after-free in efi_capsule_write
Date: Wed, 7 Sep 2022 07:54:26 -0700 [thread overview]
Message-ID: <20220907145426.GA127455@ubuntu> (raw)
In-Reply-To: <CAMj1kXHKBkP8JHUSyzEELovvSzUpfO1j2nA+eUbP-smLWjKPog@mail.gmail.com>
On Wed, Sep 07, 2022 at 04:40:08PM +0200, Ard Biesheuvel wrote:
> As far as your fix is concerned: wouldn't it be better to move the
> freeing of the pages to the release hook? Semantically, flush is not
> the right place for this, AFAICT.
you're right. Freeing the buffer in .flush is wrong.
I also think it's appropriate to move the buffer release part to .release.
But looking at the comments,
/**
* efi_capsule_flush - called by file close or file flush
* @file: file pointer
* @id: not used
*
* If a capsule is being partially uploaded then calling this function
* will be treated as upload termination and will free those completed
* buffer pages and -ECANCELED will be returned.
**/
efi_capsule_flush() seems to exist for the purpose of canceling uploads in the middle.
If buffer release is moved to .release, will there be any compatibility issues?
next prev parent reply other threads:[~2022-09-07 14:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-26 10:32 [PATCH] efi/capsule-loader: Fix use-after-free in efi_capsule_write Hyunwoo Kim
2022-09-07 8:30 ` Ard Biesheuvel
2022-09-07 10:29 ` Hyunwoo Kim
2022-09-07 14:40 ` Ard Biesheuvel
2022-09-07 14:54 ` Hyunwoo Kim [this message]
2022-09-07 15:17 ` Hyunwoo Kim
2022-09-07 15:19 ` Ard Biesheuvel
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