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In the isofs_real_read_zf function in src/isofs.c, the initialization int zf_block_size = 1 << inode->zf_block_shift; suffers from an integer overflow. This triggers undefined behavior. I believe that on i686 and x86_64, the subsequent malloc cannot be reached, but I'm not sure about other architectures. The isofs kernel module rejects zf_block_shift values greater than 17, and fuseiso should probably do the same.
Reproducer is available upon request (zf-overflow.iso).
(In reply to comment #1) > Reproducer is available upon request (zf-overflow.iso). To trigger this, a program has to attempt to open and read the "zeros" file in the ISO image.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
This bug appears to have been reported against 'rawhide' during the Fedora 23 development cycle. Changing version to '23'. (As we did not run this process for some time, it could affect also pre-Fedora 23 development cycle bugs. We are very sorry. It will help us with cleanup during Fedora 23 End Of Life. Thank you.) More information and reason for this action is here: https://fedoraproject.org/wiki/BugZappers/HouseKeeping/Fedora23
(In reply to Florian Weimer from comment #1) > Reproducer is available upon request (zf-overflow.iso). I have prepared a patch for this fix and would like to test if it works. Can you please provide me with the above named zf-overflow.iso? Thanks, Mike
Created attachment 1078999 [details] zf-overflow.iso.gz Reproducer
Created attachment 1079000 [details] Check for block size being << 2^17, if block size is exceeded, bail out
This message is a reminder that Fedora 23 is nearing its end of life. Approximately 4 (four) weeks from now Fedora will stop maintaining and issuing updates for Fedora 23. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '23'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 23 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.
This bug has been reported against a Fedora version which is already unsuported. In compliance with FESCo decision how to handle EOL of Security issues [1], I am changing the version to '27', the latest supported release. Please check whether this bug is still an issue on the '27' release. If you find this bug not being applicable on this release, please close it. [1] https://pagure.io/fesco/issue/1736
This message is a reminder that Fedora 27 is nearing its end of life. On 2018-Nov-30 Fedora will stop maintaining and issuing updates for Fedora 27. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '27'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 27 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
It appears this bug was missed in the EOL closure for F27 on 2018-11-30. If this bug still exists on supported versions, please reopen and update the version. If you cannot update the version, please needinfo the assignee.