[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
>

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

[tip-bot2 for Gary Lin]

The following commit has been merged into the efi/urgent branch of tip:

Commit-ID:     a4b81ccfd4caba017d2b84720b6de4edd16911a0
Gitweb:        https://git.kernel.org/tip/a4b81ccfd4caba017d2b84720b6de4edd16911a0
Author:        Gary Lin <glin@suse.com>
AuthorDate:    Thu, 09 Apr 2020 15:04:33 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 14 Apr 2020 08:32:16 +02:00

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

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")
Signed-off-by: Gary Lin <glin@suse.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200408081606.1504-1-glin@suse.com
Link: https://lore.kernel.org/r/20200409130434.6736-9-ardb@kernel.org
---
 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 211bb93..e0e2e81 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,