BonusAnalyzer: Add experimental non-VGA option ROM string extraction

This commit is contained in:
RichardG867
2023-11-24 17:33:20 -03:00
parent d46d5a55c0
commit 474a7aecfd
2 changed files with 34 additions and 20 deletions

View File

@@ -111,6 +111,7 @@ Depending on the contents of each BIOS, the following tags may be displayed on t
* **Build**: Build information contained within the BIOS.
* **ID**: How the BIOS identifies itself during POST.
* **LAN**: PXE or Novell NetWare RPL-compliant network boot ROM, usually associated with on-board Ethernet.
* **OROM**: Non-PCI option ROM, usually associated with on-board devices.
* **SCSI**: Adaptec or NCR/Symbios SCSI option ROM. Model (Adaptec) or SDMS version (NCR/Symbios) information is extracted from the ROM.
* **SLI**: NVIDIA SLI license for non-nForce motherboards. Model information is extracted from the license header.
* **Table**: Register table information contained within the BIOS. May help in identifying chipset and Super I/O devices.

View File

@@ -1058,7 +1058,8 @@ class BonusAnalyzer(Analyzer):
self._dmi_strings_pattern = re.compile(b'''(?:[\\x20-\\x7E]{1,255}\\x00){1,255}\\x00''')
self._dmi_date_pattern = re.compile('''[0-9]{2}/[0-9]{2}/[0-9]{2}(?:[0-9]{2})?$''')
self._ncr_pattern = re.compile(b''' SDMS \\(TM\\) V([0-9\\.]+)''')
self._orom_pattern = re.compile(b'''\\x55\\xAA([\\x01-\\xFF])[\\x00-\\xFF]{21}([\\x00-\\xFF]{4})([\\x00-\\xFF]{2}IBM)?''')
self._orom_pattern = re.compile(b'''\\x55\\xAA([\\x01-\\xFF])([\\x00-\\xFF])[\\x00-\\xFF]{20}([\\x00-\\xFF]{4})([\\x00-\\xFF]{2}IBM)?''')
self._orom_string_pattern = re.compile(b'''[\\x0D\\x0A\\x20-\\x7E]{9,}''')
self._pxe_patterns = (
re.compile(b'''PXE-M0F: Exiting '''),
re.compile(b'''PXE-EC6: UNDI driver image is invalid\\.'''),
@@ -1311,30 +1312,42 @@ class BonusAnalyzer(Analyzer):
self._enumerate_metadata('LAN', lan_roms)
# Check for the VGA BIOS compatibility marker string and add it as metadata.
vga_marker = match.group(3)
if vga_marker:
orom_marker = match.group(4)
orom_is_vga = False
if orom_marker:
orom_is_vga = True
# Find ASCII strings around the marker. There must be a space before/after
# the marker to avoid parsing of non-text bytes as ASCII characters.
vga_start = match.start(3) + 2 - rom_offset
vga_start = match.start(4) + 2 - rom_offset
if rom_data[vga_start - 1:vga_start] == b' ':
while vga_start > 0 and rom_data[vga_start - 1] >= 0x20 and rom_data[vga_start - 1] <= 0x7e:
vga_start -= 1
vga_end = match.end(3) - rom_offset
vga_end = match.end(4) - rom_offset
if rom_data[vga_end:vga_end + 1] == b' ':
while vga_end < len(rom_data) and rom_data[vga_end] >= 0x20 and rom_data[vga_end] <= 0x7e:
vga_end += 1
vga_marker = util.read_string(rom_data[vga_start:vga_end]).strip()
orom_marker = util.read_string(rom_data[vga_start:vga_end]).strip()
# Find an ASCII string after the IBM header, and if one is found, use it instead.
additional_match = self._vga_string_pattern.search(rom_data[vga_end:])
if additional_match:
vga_marker = self._vga_trim_pattern.sub('', vga_marker).strip()
if vga_marker:
vga_marker += '\n'
vga_marker += util.read_string(additional_match.group(0).replace(b'\x00', b' ')).strip()
orom_marker = self._vga_trim_pattern.sub('', orom_marker).strip()
if orom_marker:
orom_marker += '\n'
orom_marker += util.read_string(additional_match.group(0).replace(b'\x00', b' ')).strip()
elif match.group(2) in b'\xe9\xeb':
# Find ASCII strings near the header if the entry point jump looks valid.
string_match = self._orom_string_pattern.search(rom_data[5:4096]) # spec says data starts at 6, but a short jump can make it start at 5
if string_match and b'NetWare Ready ROM' in string_match.group(0): # ignore RPL signature
string_match = self._orom_string_pattern.search(rom_data[string_match.end(0):4096])
if string_match:
orom_marker = util.read_string(string_match.group(0)).strip()
if len(orom_marker) > 256: # ignore Adaptec's essay about 1 GB drives
orom_marker = None
# Extract PCI and PnP data structure pointers.
pci_header_ptr, pnp_header_ptr = struct.unpack('<HH', match.group(2))
pci_header_ptr, pnp_header_ptr = struct.unpack('<HH', match.group(3))
# Check for a valid PCI data structure.
if pci_header_ptr >= 26:
@@ -1348,8 +1361,8 @@ class BonusAnalyzer(Analyzer):
# Make sure the vendor ID is not bogus.
if vendor_id not in (0x0000, 0xffff):
# The generic VGA marker is no longer required.
vga_marker = None
# The extracted option ROM marker is no longer required.
orom_marker = None
# Add IDs to the option ROM list.
self.oroms.append((vendor_id, device_id))
@@ -1401,19 +1414,19 @@ class BonusAnalyzer(Analyzer):
# Take valid data only.
if device_id[:2] != b'\x00\x00' and (vendor or device):
# The generic VGA marker is no longer required.
vga_marker = None
# The extracted option ROM marker is no longer required.
orom_marker = None
# Add PnP ID (endianness swapped to help the front-end in
# processing it), vendor name and device name to the list.
self.oroms.append((struct.unpack('>I', device_id)[0], vendor, device))
# Add generic VGA marker if no PCI/PnP data was found.
if vga_marker:
# Add extracted option ROM marker if no PCI/PnP data was found.
if orom_marker:
# Strip lines that are too short or have a single repeated character.
stripped = (x.strip() for x in vga_marker.replace('\r', '\n').split('\n'))
vga_marker = '\n'.join(x for x in stripped if len(x) > 3 and x[:10] != (x[0] * min(len(x), 10))).strip('\n')
self.oroms.append((-1, 'VGA', vga_marker))
stripped = (x.strip() for x in orom_marker.replace('\r', '\n').split('\n'))
orom_marker = '\n'.join(x for x in stripped if len(x) > 3 and x[:10] != (x[0] * min(len(x), 10))).strip('\n')
self.oroms.append((-1, 'VGA' if orom_is_vga else 'OROM', orom_marker))
# This analyzer should never return True.
return False