linux-kernel - Re: [PATCH] efi: fix a race and a buffer overflow while reading efivars via sysfs

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Message-ID: <925307051.13073500.1583336716147.JavaMail.zimbra@redhat.com>
Date:   Wed, 4 Mar 2020 10:45:16 -0500 (EST)
From:   Vladis Dronov <vdronov@...hat.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi: fix a race and a buffer overflow while reading
 efivars via sysfs

Hello, Ard,

> Wouldn't it be easier to pass a var_data_size stack variable into
> efivar_entry_get(), and only update the value in 'var' if it is <=
> 1024?

I have prepared a v2 patch with an approach you suggest and will send it
out shortly. It indeed simpler and fixes only the overflow bug mentioned.

Could you, please, review it and if you like it, probably, accept it?
In case I've implemented your idea incorrectly, could you, please,
correct me?

Best regards,
Vladis Dronov | Red Hat, Inc. | The Core Kernel | Senior Software Engineer