linux-kernel - Re: [PATCH v2 2/2] ima: Free IMA measurement buffer after kexec syscall

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Date:   Fri, 5 Feb 2021 11:05:48 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
Cc:     zohar@...ux.ibm.com, bauerman@...ux.ibm.com,
        dmitry.kasatkin@...il.com, ebiederm@...ssion.com,
        sashal@...nel.org, tyhicks@...ux.microsoft.com,
        linux-integrity@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] ima: Free IMA measurement buffer after kexec
 syscall

On Thu, Feb 04, 2021 at 09:49:51AM -0800, Lakshmi Ramasubramanian wrote:
> IMA allocates kernel virtual memory to carry forward the measurement
> list, from the current kernel to the next kernel on kexec system call,
> in ima_add_kexec_buffer() function.  This buffer is not freed before
> completing the kexec system call resulting in memory leak.
> 
> Add ima_buffer field in "struct kimage" to store the virtual address
> of the buffer allocated for the IMA measurement list.
> Free the memory allocated for the IMA measurement list in
> kimage_file_post_load_cleanup() function.
> 
> Signed-off-by: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
> Suggested-by: Tyler Hicks <tyhicks@...ux.microsoft.com>
> Reviewed-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
> Reviewed-by: Tyler Hicks <tyhicks@...ux.microsoft.com>
> Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")
> ---
>  include/linux/kexec.h              | 5 +++++
>  kernel/kexec_file.c                | 5 +++++
>  security/integrity/ima/ima_kexec.c | 2 ++
>  3 files changed, 12 insertions(+)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>