From: Nathan Lynch <nathanl@linux•ibm.com>
To: Andrew Donnellan <ajd@linux•ibm.com>, linuxppc-dev@lists•ozlabs.org
Cc: Leonardo Bras <leobras.c@gmail•com>, linux-hardening@vger•kernel.org
Subject: Re: [PATCH] powerpc/rtas: Replace one-element arrays with flexible arrays
Date: Fri, 27 Jan 2023 07:10:28 -0600 [thread overview]
Message-ID: <87357wp1h7.fsf@linux.ibm.com> (raw)
In-Reply-To: <20230127085023.271674-1-ajd@linux.ibm.com>
Andrew Donnellan <ajd@linux•ibm.com> writes:
> Using a one-element array as a fake flexible array is deprecated.
>
> Replace the one-element flexible arrays in rtas-types.h with C99 standard
> flexible array members instead.
>
> This helps us move towards enabling -fstrict-flex-arrays=3 in future.
>
> Found using scripts/coccinelle/misc/flexible_array.cocci.
>
> Cc: Nathan Lynch <nathanl@linux•ibm.com>
> Cc: Leonardo Bras <leobras.c@gmail•com>
> Cc: linux-hardening@vger•kernel.org
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/79
> Signed-off-by: Andrew Donnellan <ajd@linux•ibm.com>
> ---
> arch/powerpc/include/asm/rtas-types.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/rtas-types.h b/arch/powerpc/include/asm/rtas-types.h
> index 8df6235d64d1..40ec03a05c0b 100644
> --- a/arch/powerpc/include/asm/rtas-types.h
> +++ b/arch/powerpc/include/asm/rtas-types.h
> @@ -44,7 +44,7 @@ struct rtas_error_log {
> */
> u8 byte3; /* General event or error*/
> __be32 extended_log_length; /* length in bytes */
> - unsigned char buffer[1]; /* Start of extended log */
> + unsigned char buffer[]; /* Start of extended log */
> /* Variable length. */
> };
>
> @@ -85,7 +85,7 @@ struct rtas_ext_event_log_v6 {
> /* that defines the format for */
> /* the vendor specific log type */
> /* Byte 16-end of log */
> - u8 vendor_log[1]; /* Start of vendor specific log */
> + u8 vendor_log[]; /* Start of vendor specific log */
> /* Variable length. */
> };
I see at least one place that consults the size of one of these structs,
in get_pseries_errorlog():
/* Check that we understand the format */
if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) || ...
Don't all such sites need to be audited/adjusted for changes like this?
next prev parent reply other threads:[~2023-01-27 13:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 8:50 [PATCH] powerpc/rtas: Replace one-element arrays with flexible arrays Andrew Donnellan
2023-01-27 8:59 ` Leonardo Brás
2023-01-27 13:10 ` Nathan Lynch [this message]
2023-01-27 19:23 ` Kees Cook
2023-04-20 7:46 ` Andrew Donnellan
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