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Message-ID: <706e63abf12b9cf76d43cf67999cbb7baa06ebb0.camel@linux.intel.com>
Subject: Re: [PATCH] drm/xe: replace format-less snprintf() with strscpy()
From: Thomas =?ISO-8859-1?Q?Hellstr=F6m?= <thomas.hellstrom@linux.intel.com>
To: Arnd Bergmann <arnd@kernel.org>, Lucas De Marchi
 <lucas.demarchi@intel.com>,  Oded Gabbay <ogabbay@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>, Maarten Lankhorst
 <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, 
 Thomas Zimmermann <tzimmermann@suse.de>, David Airlie <airlied@gmail.com>,
 Daniel Vetter <daniel@ffwll.ch>, Rodrigo Vivi <rodrigo.vivi@intel.com>,
 =?ISO-8859-1?Q?Jos=E9?= Roberto de Souza <jose.souza@intel.com>, Matthew
 Brost <matthew.brost@intel.com>, Francois Dugast
 <francois.dugast@intel.com>, Himal Prasad Ghimiray
 <himal.prasad.ghimiray@intel.com>,  intel-xe@lists.freedesktop.org,
 dri-devel@lists.freedesktop.org,  linux-kernel@vger.kernel.org
Date: Tue, 28 May 2024 16:46:02 +0200
In-Reply-To: <20240528133251.2310868-1-arnd@kernel.org>
References: <20240528133251.2310868-1-arnd@kernel.org>
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On Tue, 2024-05-28 at 15:32 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>=20
> Using snprintf() with a format string from task->comm is a bit
> dangerous since the string may be controlled by unprivileged
> userspace:
>=20
> drivers/gpu/drm/xe/xe_devcoredump.c: In function
> 'devcoredump_snapshot':
> drivers/gpu/drm/xe/xe_devcoredump.c:184:9: error: format not a string
> literal and no format arguments [-Werror=3Dformat-security]
> =C2=A0 184 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 snprintf(ss-=
>process_name, sizeof(ss->process_name),
> process_name);
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0 ^~~~~~~~
>=20
> In this case there is no reason for an snprintf(), so use a simpler
> string copy.
>=20
> Fixes: b10d0c5e9df7 ("drm/xe: Add process name to devcoredump")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Hellstr=C3=B6m <thomas.hellstrom@linux.intel.com>

Thanks,

Will pick up and apply as soon as our CI is fit for fight.
/Thomas


> ---
> =C2=A0drivers/gpu/drm/xe/xe_devcoredump.c | 2 +-
> =C2=A01 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c
> b/drivers/gpu/drm/xe/xe_devcoredump.c
> index 1643d44f8bc4..1973bfaece40 100644
> --- a/drivers/gpu/drm/xe/xe_devcoredump.c
> +++ b/drivers/gpu/drm/xe/xe_devcoredump.c
> @@ -181,7 +181,7 @@ static void devcoredump_snapshot(struct
> xe_devcoredump *coredump,
> =C2=A0		if (task)
> =C2=A0			process_name =3D task->comm;
> =C2=A0	}
> -	snprintf(ss->process_name, sizeof(ss->process_name),
> process_name);
> +	strscpy(ss->process_name, process_name);
> =C2=A0	if (task)
> =C2=A0		put_task_struct(task);
> =C2=A0