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Message-ID: <b4bzeghwifymbahgtjrehyulb3ezljaexwwqsjnj4utk2koroz@zsru65co3ufp>
Date: Mon, 7 Apr 2025 23:20:41 +0200
From: Alejandro Colomar <alx@...nel.org>
To: Kees Cook <kees@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Maciej W. Rozycki" <macro@...am.me.uk>, Azeem Shaikh <azeemshaikh38@...il.com>,
Alex Elder <elder@...nel.org>, Sumit Garg <sumit.garg@...nel.org>, linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org
Subject: Re: [PATCH v2] EISA: Increase length of device names
Hi Kees,
On Mon, Apr 07, 2025 at 10:29:35AM -0700, Kees Cook wrote:
> GCC 15's -Wunterminated-string-initialization warned about truncated
> name strings. Instead of marking them with the "nonstring" attribute[1],
> increase their length to correctly include enough space for the
> terminating NUL character, as they are used with %s format specifiers
> when showing resource allocations in /proc/ioports:
>
> seq_printf(m, "%*s%0*llx-%0*llx : %s\n", ..., r->name);
>
> The strings in eisa.ids have a max length of 73, and the 50 limit was an
> arbitrary limit that was removed back in 2008 with commit ca52a49846f1
> ("driver core: remove DEVICE_NAME_SIZE define"). Change the limit to 74
> so nothing is truncated any more.
>
> Additionally fix the Makefile to use "if_changed" instead of "cmd"
> to detect changes to the command line used to generate the target,
> otherwise devlist.h won't be rebuilt.
>
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
> Signed-off-by: Kees Cook <kees@...nel.org>
> ---
> Cc: Alejandro Colomar <alx@...nel.org>
Acked-by: Alejandro Colomar <alx@...nel.org>
> Cc: "Maciej W. Rozycki" <macro@...am.me.uk>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Azeem Shaikh <azeemshaikh38@...il.com>
> Cc: Alex Elder <elder@...nel.org>
> Cc: Sumit Garg <sumit.garg@...nel.org>
>
> v2: crank length to 74 for full coverage and fix Makefile too
> v1: https://lore.kernel.org/lkml/20250310222424.work.107-kees@kernel.org/
> ---
> drivers/eisa/Makefile | 11 ++++-------
> drivers/eisa/eisa-bus.c | 2 +-
> include/linux/eisa.h | 5 ++++-
> 3 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/eisa/Makefile b/drivers/eisa/Makefile
> index a1dd0eaec2d4..f0d6cf7d1f32 100644
> --- a/drivers/eisa/Makefile
> +++ b/drivers/eisa/Makefile
> @@ -1,7 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0
> # Makefile for the Linux device tree
>
> -obj-$(CONFIG_EISA) += eisa-bus.o
> +obj-$(CONFIG_EISA) += devlist.h eisa-bus.o
> obj-${CONFIG_EISA_PCI_EISA} += pci_eisa.o
>
> # virtual_root.o should be the last EISA root device to initialize,
> @@ -9,14 +9,11 @@ obj-${CONFIG_EISA_PCI_EISA} += pci_eisa.o
> obj-${CONFIG_EISA_VIRTUAL_ROOT} += virtual_root.o
>
>
> -# Ugly hack to get DEVICE_NAME_SIZE value...
> -DEVICE_NAME_SIZE = 50
> -
> $(obj)/eisa-bus.o: $(obj)/devlist.h
>
> quiet_cmd_eisaid = GEN $@
> - cmd_eisaid = sed -e '/^\#/D' -e 's/^\([[:alnum:]]\{7\}\) \+"\([^"]\{1,$(DEVICE_NAME_SIZE)\}\).*"/EISA_DEVINFO ("\1", "\2"),/' $< > $@
> + cmd_eisaid = sed -e '/^\#/D' -e 's/^\([[:alnum:]]\{7\}\) \+"\([^"]* \) "/EISA_DEVINFO ("\1", "\2"),/' $< > $@
LGTM.
Have a lovely night!
Alex
>
> clean-files := devlist.h
> -$(obj)/devlist.h: $(src)/eisa.ids include/linux/device.h
> - $(call cmd,eisaid)
> +$(obj)/devlist.h: $(src)/eisa.ids include/linux/device.h FORCE
> + $(call if_changed,eisaid)
> diff --git a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
> index cb586a362944..edceea083b98 100644
> --- a/drivers/eisa/eisa-bus.c
> +++ b/drivers/eisa/eisa-bus.c
> @@ -21,7 +21,7 @@
>
> struct eisa_device_info {
> struct eisa_device_id id;
> - char name[50];
> + char name[EISA_DEVICE_INFO_NAME_SIZE];
> };
>
> #ifdef CONFIG_EISA_NAMES
> diff --git a/include/linux/eisa.h b/include/linux/eisa.h
> index f98200cae637..21a2ecc1e538 100644
> --- a/include/linux/eisa.h
> +++ b/include/linux/eisa.h
> @@ -28,6 +28,9 @@
> #define EISA_CONFIG_ENABLED 1
> #define EISA_CONFIG_FORCED 2
>
> +/* Chosen to hold the longest string in eisa.ids. */
> +#define EISA_DEVICE_INFO_NAME_SIZE 74
> +
> /* There is not much we can say about an EISA device, apart from
> * signature, slot number, and base address. dma_mask is set by
> * default to parent device mask..*/
> @@ -41,7 +44,7 @@ struct eisa_device {
> u64 dma_mask;
> struct device dev; /* generic device */
> #ifdef CONFIG_EISA_NAMES
> - char pretty_name[50];
> + char pretty_name[EISA_DEVICE_INFO_NAME_SIZE];
> #endif
> };
>
> --
> 2.34.1
>
--
<https://www.alejandro-colomar.es/>
<https://www.alejandro-colomar.es:8443/>
<http://www.alejandro-colomar.es:8080/>
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