[edk2-devel] [edk2 PATCH 40/48] OvmfPkg/VirtioFsDxe: handle the volume label in EFI_FILE_PROTOCOL.SetInfo
Laszlo Ersek
lersek at redhat.com
Wed Dec 16 21:11:17 UTC 2020
The least complicated third of EFI_FILE_PROTOCOL.SetInfo() is to handle
the EFI_FILE_SYSTEM_INFO and EFI_FILE_SYSTEM_VOLUME_LABEL setting
requests. Both of those can only change the volume label -- which the
Virtio Filesystem device does not support.
Verify the input for well-formedness, and report success only if the
volume label is being set to its current value.
Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Philippe Mathieu-Daudé <philmd at redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek at redhat.com>
---
OvmfPkg/VirtioFsDxe/SimpleFsSetInfo.c | 226 +++++++++++++++++++-
1 file changed, 225 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/VirtioFsDxe/SimpleFsSetInfo.c b/OvmfPkg/VirtioFsDxe/SimpleFsSetInfo.c
index 200b7a1bcd20..895b5c029a9e 100644
--- a/OvmfPkg/VirtioFsDxe/SimpleFsSetInfo.c
+++ b/OvmfPkg/VirtioFsDxe/SimpleFsSetInfo.c
@@ -1,21 +1,245 @@
/** @file
EFI_FILE_PROTOCOL.SetInfo() member function for the Virtio Filesystem driver.
Copyright (C) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
+#include <Guid/FileSystemInfo.h> // gEfiFileSystemInfoGuid
+#include <Guid/FileSystemVolumeLabelInfo.h> // gEfiFileSystemVolumeLabelInfo...
+#include <Library/BaseLib.h> // StrCmp()
+#include <Library/BaseMemoryLib.h> // CompareGuid()
+
#include "VirtioFsDxe.h"
+/**
+ Validate a buffer that the EFI_FILE_PROTOCOL.SetInfo() caller passes in for a
+ particular InformationType GUID.
+
+ The structure to be validated is supposed to end with a variable-length,
+ NUL-terminated CHAR16 Name string.
+
+ @param[in] SizeByProtocolCaller The BufferSize parameter as provided by the
+ EFI_FILE_PROTOCOL.SetInfo() caller.
+
+ @param[in] MinimumStructSize The minimum structure size that is required
+ for the given InformationType GUID,
+ including a single CHAR16 element from the
+ trailing Name field.
+
+ @param[in] IsSizeByInfoPresent TRUE if and only if the expected structure
+ starts with a UINT64 Size field that reports
+ the actual structure size.
+
+ @param[in] Buffer The Buffer parameter as provided by the
+ EFI_FILE_PROTOCOL.SetInfo() caller.
+
+ @retval EFI_SUCCESS Validation successful, Buffer is well-formed.
+
+ @retval EFI_BAD_BUFFER_SIZE The EFI_FILE_PROTOCOL.SetInfo()
+ caller provided a BufferSize that is smaller
+ than the minimum structure size required for
+ the given InformationType GUID.
+
+ @retval EFI_INVALID_PARAMETER IsSizeByInfoPresent is TRUE, and the leading
+ UINT64 Size field does not match the
+ EFI_FILE_PROTOCOL.SetInfo() caller-provided
+ BufferSize.
+
+ @retval EFI_INVALID_PARAMETER The trailing Name field does not consist of a
+ whole multiple of CHAR16 elements.
+
+ @retval EFI_INVALID_PARAMETER The trailing Name field is not NUL-terminated.
+**/
+STATIC
+EFI_STATUS
+ValidateInfoStructure (
+ IN UINTN SizeByProtocolCaller,
+ IN UINTN MinimumStructSize,
+ IN BOOLEAN IsSizeByInfoPresent,
+ IN VOID *Buffer
+ )
+{
+ UINTN NameFieldByteOffset;
+ UINTN NameFieldBytes;
+ UINTN NameFieldChar16s;
+ CHAR16 *NameField;
+
+ //
+ // Make sure the internal function asking for validation passes in sane
+ // values.
+ //
+ ASSERT (MinimumStructSize >= sizeof (CHAR16));
+ NameFieldByteOffset = MinimumStructSize - sizeof (CHAR16);
+
+ if (IsSizeByInfoPresent) {
+ ASSERT (MinimumStructSize >= sizeof (UINT64) + sizeof (CHAR16));
+ ASSERT (NameFieldByteOffset >= sizeof (UINT64));
+ }
+
+ //
+ // Check whether the protocol caller provided enough bytes for the minimum
+ // size of this info structure.
+ //
+ if (SizeByProtocolCaller < MinimumStructSize) {
+ return EFI_BAD_BUFFER_SIZE;
+ }
+
+ //
+ // If the info structure starts with a UINT64 Size field, check if that
+ // agrees with the protocol caller-provided size.
+ //
+ if (IsSizeByInfoPresent) {
+ UINT64 *SizeByInfo;
+
+ SizeByInfo = Buffer;
+ if (*SizeByInfo != SizeByProtocolCaller) {
+ return EFI_INVALID_PARAMETER;
+ }
+ }
+
+ //
+ // The CHAR16 Name field at the end of the structure must have an even number
+ // of bytes.
+ //
+ // The subtraction below cannot underflow, and yields at least
+ // sizeof(CHAR16).
+ //
+ ASSERT (SizeByProtocolCaller >= NameFieldByteOffset);
+ NameFieldBytes = SizeByProtocolCaller - NameFieldByteOffset;
+ ASSERT (NameFieldBytes >= sizeof (CHAR16));
+ if (NameFieldBytes % sizeof (CHAR16) != 0) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // The CHAR16 Name field at the end of the structure must be NUL-terminated.
+ //
+ NameFieldChar16s = NameFieldBytes / sizeof (CHAR16);
+ ASSERT (NameFieldChar16s >= 1);
+
+ NameField = (CHAR16 *)((UINT8 *)Buffer + NameFieldByteOffset);
+ if (NameField[NameFieldChar16s - 1] != L'\0') {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ return EFI_SUCCESS;
+}
+
+/**
+ Process an EFI_FILE_SYSTEM_INFO setting request.
+**/
+STATIC
+EFI_STATUS
+SetFileSystemInfo (
+ IN EFI_FILE_PROTOCOL *This,
+ IN UINTN BufferSize,
+ IN VOID *Buffer
+ )
+{
+ VIRTIO_FS_FILE *VirtioFsFile;
+ VIRTIO_FS *VirtioFs;
+ EFI_STATUS Status;
+ EFI_FILE_SYSTEM_INFO *FileSystemInfo;
+
+ VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
+ VirtioFs = VirtioFsFile->OwnerFs;
+
+ //
+ // Validate if Buffer passes as EFI_FILE_SYSTEM_INFO.
+ //
+ Status = ValidateInfoStructure (
+ BufferSize, // SizeByProtocolCaller
+ OFFSET_OF (EFI_FILE_SYSTEM_INFO,
+ VolumeLabel) + sizeof (CHAR16), // MinimumStructSize
+ TRUE, // IsSizeByInfoPresent
+ Buffer
+ );
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+ FileSystemInfo = Buffer;
+
+ //
+ // EFI_FILE_SYSTEM_INFO fields other than VolumeLabel cannot be changed, per
+ // spec.
+ //
+ // If the label is being changed to its current value, report success;
+ // otherwise, reject the request, as the Virtio Filesystem device does not
+ // support changing the label.
+ //
+ if (StrCmp (FileSystemInfo->VolumeLabel, VirtioFs->Label) == 0) {
+ return EFI_SUCCESS;
+ }
+ return EFI_WRITE_PROTECTED;
+}
+
+/**
+ Process an EFI_FILE_SYSTEM_VOLUME_LABEL setting request.
+**/
+STATIC
+EFI_STATUS
+SetFileSystemVolumeLabelInfo (
+ IN EFI_FILE_PROTOCOL *This,
+ IN UINTN BufferSize,
+ IN VOID *Buffer
+ )
+{
+ VIRTIO_FS_FILE *VirtioFsFile;
+ VIRTIO_FS *VirtioFs;
+ EFI_STATUS Status;
+ EFI_FILE_SYSTEM_VOLUME_LABEL *FileSystemVolumeLabel;
+
+ VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
+ VirtioFs = VirtioFsFile->OwnerFs;
+
+ //
+ // Validate if Buffer passes as EFI_FILE_SYSTEM_VOLUME_LABEL.
+ //
+ Status = ValidateInfoStructure (
+ BufferSize, // SizeByProtocolCaller
+ OFFSET_OF (EFI_FILE_SYSTEM_VOLUME_LABEL,
+ VolumeLabel) + sizeof (CHAR16), // MinimumStructSize
+ FALSE, // IsSizeByInfoPresent
+ Buffer
+ );
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+ FileSystemVolumeLabel = Buffer;
+
+ //
+ // If the label is being changed to its current value, report success;
+ // otherwise, reject the request, as the Virtio Filesystem device does not
+ // support changing the label.
+ //
+ if (StrCmp (FileSystemVolumeLabel->VolumeLabel, VirtioFs->Label) == 0) {
+ return EFI_SUCCESS;
+ }
+ return EFI_WRITE_PROTECTED;
+}
+
EFI_STATUS
EFIAPI
VirtioFsSimpleFileSetInfo (
IN EFI_FILE_PROTOCOL *This,
IN EFI_GUID *InformationType,
IN UINTN BufferSize,
IN VOID *Buffer
)
{
- return EFI_NO_MEDIA;
+ if (CompareGuid (InformationType, &gEfiFileInfoGuid)) {
+ return EFI_UNSUPPORTED;
+ }
+
+ if (CompareGuid (InformationType, &gEfiFileSystemInfoGuid)) {
+ return SetFileSystemInfo (This, BufferSize, Buffer);
+ }
+
+ if (CompareGuid (InformationType, &gEfiFileSystemVolumeLabelInfoIdGuid)) {
+ return SetFileSystemVolumeLabelInfo (This, BufferSize, Buffer);
+ }
+
+ return EFI_UNSUPPORTED;
}
--
2.19.1.3.g30247aa5d201
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