Re: [PATCH] efi: fix return value of __setup handlers

[Ard Biesheuvel]

On Tue, 1 Mar 2022 at 05:19, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> When "dump_apple_properties" is used on the kernel boot command line,
> it causes an Unknown parameter message and the string is added to init's
> argument strings:
>
>   Unknown kernel command line parameters "dump_apple_properties
>     BOOT_IMAGE=/boot/bzImage-517rc6 efivar_ssdt=newcpu_ssdt", will be
>     passed to user space.
>
>  Run /sbin/init as init process
>    with arguments:
>      /sbin/init
>      dump_apple_properties
>    with environment:
>      HOME=/
>      TERM=linux
>      BOOT_IMAGE=/boot/bzImage-517rc6
>      efivar_ssdt=newcpu_ssdt
>
> Similarly when "efivar_ssdt=somestring" is used, it is added to the
> Unknown parameter message and to init's environment strings, polluting
> them (see examples above).
>
> Change the return value of the __setup functions to 1 to indicate
> that the __setup options have been handled.
>
> Fixes: 58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
> Fixes: 475fb4e8b2f4 ("efi / ACPI: load SSTDs from EFI variables")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Reported-by: Igor Zhbanov <i.zhbanov@xxxxxxxxxxxx>
> Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx
> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Cc: linux-efi@xxxxxxxxxxxxxxx
> Cc: Lukas Wunner <lukas@xxxxxxxxx>
> Cc: Octavian Purdila <octavian.purdila@xxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>

Queued as a fix,

Thanks,
Ard.

> ---
>  drivers/firmware/efi/apple-properties.c |    2 +-
>  drivers/firmware/efi/efi.c              |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> --- linux-next-20220228.orig/drivers/firmware/efi/apple-properties.c
> +++ linux-next-20220228/drivers/firmware/efi/apple-properties.c
> @@ -24,7 +24,7 @@ static bool dump_properties __initdata;
>  static int __init dump_properties_enable(char *arg)
>  {
>         dump_properties = true;
> -       return 0;
> +       return 1;
>  }
>
>  __setup("dump_apple_properties", dump_properties_enable);
> --- linux-next-20220228.orig/drivers/firmware/efi/efi.c
> +++ linux-next-20220228/drivers/firmware/efi/efi.c
> @@ -212,7 +212,7 @@ static int __init efivar_ssdt_setup(char
>                 memcpy(efivar_ssdt, str, strlen(str));
>         else
>                 pr_warn("efivar_ssdt: name too long: %s\n", str);
> -       return 0;
> +       return 1;
>  }
>  __setup("efivar_ssdt=", efivar_ssdt_setup);
>