[PATCH] efi/x86: Fix the deletion of variables in mixed mode

[PATCH] efi/x86: Fix the deletion of variables in mixed mode

[Gary Lin]

efi_thunk_set_variable() treated the NULL "data" pointer as an invalid
parameter, and this broke the deletion of variables in mixed mode.
This commit fixes the check of data so that the userspace program can
delete a variable in mixed mode.

Fixes: 8319e9d5ad98ffcc ("efi/x86: Handle by-ref arguments covering multiple pages in mixed mode")
Cc: linux-efi@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Gary Lin <glin@suse.com>
---
 arch/x86/platform/efi/efi_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 211bb9358b73..e0e2e8136cf5 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -638,7 +638,7 @@ efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
 	phys_vendor = virt_to_phys_or_null(vnd);
 	phys_data = virt_to_phys_or_null_size(data, data_size);
 
-	if (!phys_name || !phys_data)
+	if (!phys_name || (data && !phys_data))
 		status = EFI_INVALID_PARAMETER;
 	else
 		status = efi_thunk(set_variable, phys_name, phys_vendor,
@@ -669,7 +669,7 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
 	phys_vendor = virt_to_phys_or_null(vnd);
 	phys_data = virt_to_phys_or_null_size(data, data_size);
 
-	if (!phys_name || !phys_data)
+	if (!phys_name || (data && !phys_data))
 		status = EFI_INVALID_PARAMETER;
 	else
 		status = efi_thunk(set_variable, phys_name, phys_vendor,
-- 
2.25.1

Re: [PATCH] efi/x86: Fix the deletion of variables in mixed mode

[Ard Biesheuvel]

On Wed, 8 Apr 2020 at 10:18, Gary Lin <glin@suse.com> wrote:
>
> efi_thunk_set_variable() treated the NULL "data" pointer as an invalid
> parameter, and this broke the deletion of variables in mixed mode.
> This commit fixes the check of data so that the userspace program can
> delete a variable in mixed mode.
>
> Fixes: 8319e9d5ad98ffcc ("efi/x86: Handle by-ref arguments covering multiple pages in mixed mode")
> Cc: linux-efi@vger.kernel.org
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Gary Lin <glin@suse.com>

Thanks Gary.

I'll queue this in efi/urgent.



> ---
>  arch/x86/platform/efi/efi_64.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 211bb9358b73..e0e2e8136cf5 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -638,7 +638,7 @@ efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
>         phys_vendor = virt_to_phys_or_null(vnd);
>         phys_data = virt_to_phys_or_null_size(data, data_size);
>
> -       if (!phys_name || !phys_data)
> +       if (!phys_name || (data && !phys_data))
>                 status = EFI_INVALID_PARAMETER;
>         else
>                 status = efi_thunk(set_variable, phys_name, phys_vendor,
> @@ -669,7 +669,7 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
>         phys_vendor = virt_to_phys_or_null(vnd);
>         phys_data = virt_to_phys_or_null_size(data, data_size);
>
> -       if (!phys_name || !phys_data)
> +       if (!phys_name || (data && !phys_data))
>                 status = EFI_INVALID_PARAMETER;
>         else
>                 status = efi_thunk(set_variable, phys_name, phys_vendor,
> --
> 2.25.1
>