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Fix #11 - read_regions bug which caused incorrect encryption/decryption

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This commit is contained in:
Nichlas Severinsen 2022-02-19 00:21:51 +01:00
parent 79f303be57
commit fef4eee23a
1 changed files with 30 additions and 20 deletions
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50
libray/iso.py
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@ -53,28 +53,38 @@ class ISO:
NUM_INFO_BYTES = 4
def read_regions(self, input_iso, filename):
def read_regions(self, input_iso):
"""List with info dict (start, end, whether it's encrypted) for every region.
Basically, every other (odd numbered) region is encrypted.
"""
regions = []
# The first region is always unencrypted
encrypted = False
for _ in range(0, self.number_of_regions):
regions.append({
'start': core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * core.SECTOR,
'end': core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * core.SECTOR,
'enc': encrypted
})
regions = [{
'start': core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * core.SECTOR, # Should always be 0?
'end': core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * core.SECTOR + core.SECTOR,
'enc': encrypted
}]
input_iso.seek(input_iso.tell() - self.NUM_INFO_BYTES)
# We'll read 4 bytes until we hit a non-size (<=0)
while True:
encrypted = not encrypted
# Last region might not actually be 2048 bytes, so we'll just cheat
regions[-1]['end'] = self.size
end = core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * core.SECTOR
if not end:
break
regions.append({
'start': regions[-1]['end'],
'end': end + core.SECTOR - (core.SECTOR if encrypted else 0),
'enc': encrypted
})
return regions
@ -88,13 +98,13 @@ class ISO:
core.error('looks like ISO file/mount is empty?')
with open(args.iso, 'rb') as input_iso:
# Get number of regions (times two as the number represents both encrypted and decrypted regions )
self.number_of_regions = core.to_int(input_iso.read(self.NUM_INFO_BYTES)) * 2
# Get number of unencrypted regions
self.number_of_unencrypted_regions = core.to_int(input_iso.read(self.NUM_INFO_BYTES))
# Skip unused bytes
input_iso.seek(input_iso.tell() + self.NUM_INFO_BYTES)
self.regions = self.read_regions(input_iso, args.iso)
self.regions = self.read_regions(input_iso)
# Seek to the start of sector 2, '+ 16' skips a section containing some 'playstation'
input_iso.seek(core.SECTOR + 16)
@ -228,8 +238,8 @@ class ISO:
self.ird = ird.IRD(args.ird)
if self.ird.region_count != len(self.regions)-1:
core.error('Corrupt ISO or error in IRD. Expected %s regions, found %s regions' % (self.ird.region_count, len(self.regions)-1))
if self.ird.region_count != len(self.regions):
core.error('Corrupt ISO or error in IRD. Expected %s regions, found %s regions' % (self.ird.region_count, len(self.regions)))
if self.regions[-1]['start'] > self.size:
core.error('Corrupt ISO or error in IRD. Expected filesize larger than %.2f GiB, actual size is %.2f GiB' % (self.regions[-1]['start'] / 1024**3, self.size / 1024**3 ) )
@ -242,8 +252,8 @@ class ISO:
self.ird = ird.IRD(args.ird)
if self.ird.region_count != len(self.regions)-1:
core.error('Corrupt ISO or error in IRD. Expected %s regions, found %s regions' % (self.ird.region_count, len(self.regions)-1))
if self.ird.region_count != len(self.regions):
core.error('Corrupt ISO or error in IRD. Expected %s regions, found %s regions' % (self.ird.region_count, len(self.regions)))
if self.regions[-1]['start'] > self.size:
core.error('Corrupt ISO or error in IRD. Expected filesize larger than %.2f GiB, actual size is %.2f GiB' % (self.regions[-1]['start'] / 1024**3, self.size / 1024**3 ) )
@ -387,7 +397,7 @@ class ISO:
print('Game ID: %s' % self.game_id)
print('Key: %s' % self.disc_key.hex())
print('Info from ISO:')
print('Regions: %s' % self.number_of_regions)
print('Unencrypted regions: %s' % self.number_of_unencrypted_regions)
for i, region in enumerate(self.regions):
print(i, region)
print(i, region, region['start'] // core.SECTOR, region['end'] // core.SECTOR)