Do not crash when parsing System Use field (of Directory Record) if ISO missing the padding bit #164
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
… if the padding bit is missing and no space for SU
nekrich
approved these changes
Jan 17, 2024
alek-prykhodko
approved these changes
Jan 17, 2024
PaulTaykalo
approved these changes
Jan 17, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
According to ISO 9660 standard when parsing Directory Record (section 9.1) and the File Identifier (file name) length is an even number, a padding bit of value 0x0 should be followed the file File Identifier bit (section 9.1.12); Some of the ISO tools doesn't add the padding field which leads to the parser crash.
More explanation
From the existing code:
systemlength=recordlength-33-namelength-((namelength&1)^1);systemlength- System Use record length (part of Directory record)recordlength- Directory Record length (part of Directory record)33- the offset of the File Identifier (part of Directory record)namelength- length of the File Identifier record (part of Directory Record)-((namelength&1)^1)if namelength is even number, return -1and so, if there is no padding byte after file name and System Usage record is 0, systemlength equals to -1, and
if(systemlength)calls the body