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

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 211bb93..e0e2e81 100644 (file)
--- 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,