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Add warning if fv header checksum is invalid

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Signed-off-by: brentholtsclaw <brent.holtsclaw@intel.com>
This commit is contained in:
brentholtsclaw
2022-06-06 15:04:28 -07:00
committed by Nathaniel Mitchell
parent 54ed1f4784
commit 5d8fce5ad1
1 changed files with 4 additions and 2 deletions
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chipsec/hal/uefi_fv.py
+4 -2
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@@ -243,12 +243,14 @@ def FvSum16(buffer):
def FvChecksum16(buffer):
return ((0x10000 - FvSum16(buffer)) & 0xffff)
def ValidateFwVolumeHeader(ZeroVector, FsGuid, FvLength, HeaderLength, ExtHeaderOffset, Reserved, size):
def ValidateFwVolumeHeader(ZeroVector, FsGuid, FvLength, HeaderLength, ExtHeaderOffset, Reserved, size, Calcsum, Checksum):
# zero_vector = (ZeroVector == '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
fv_rsvd = (Reserved == 0)
# fs_guid = (FsGuid in (EFI_FS_GUIDS + [VARIABLE_STORE_FV_GUID]))
fv_len = (FvLength <= size)
fv_header_len = (ExtHeaderOffset < FvLength) and (HeaderLength < FvLength)
if Checksum != Calcsum:
logger().log_warning("Firmware Volume {{{}}} checksum does not match calculated checksum".format(FsGuid))
return fv_rsvd and fv_len and fv_header_len
def NextFwVolume(buffer, off = 0):
@@ -276,7 +278,7 @@ def NextFwVolume(buffer, off = 0):
fvh = fvh + tail
CalcSum = FvChecksum16(fvh)
FsGuid = UUID(bytes_le=FileSystemGuid0)
if (ValidateFwVolumeHeader(ZeroVector, FsGuid, FvLength, HeaderLength, ExtHeaderOffset, Reserved, size)):
if (ValidateFwVolumeHeader(ZeroVector, FsGuid, FvLength, HeaderLength, ExtHeaderOffset, Reserved, size, CalcSum, Checksum)):
return EFI_FV(fof, FsGuid, FvLength, Attributes, HeaderLength, Checksum, ExtHeaderOffset, buffer[fof:fof +FvLength], CalcSum)
else:
fof += 0x2C