On Sat 21 Dec 2019 at 23:21:35 +0100, Thomas Schmitt wrote: > Hi, > > > I am extracting files from a Debian ISO as follows: > > xorriso -osirrox on -md5 on -indev debian-10.2.0-i386-DVD-10.iso -extract > > pool/main test/ > > Will the files in test/ have the same md5sum as the ones in the ISO? > > The first problem with this wish is that Debian ISOs are not created with MD5 > checksums on libisofs level. So xorriso cannot check the ISO and its data file > contents for alterations. > > The overall integrity of an ISO can be verified by its lines in the various > *SUMS files which accompany the ISO images in their download directories. > The integrity of *SUMS can be verified by the *SUMS.sign files. > For an example see > https://wiki.debian.org/JigdoOnLive#Verify_the_Debian_Live_download > > If debian-10.2.0-i386-DVD-10.iso passes this verification and your disk > hardware is healthy, then you can trust on getting extracted undamaged files.
This will do me. > Nevertheless, since you are downloading a pool of .deb files, you may verify > them by Debian's means after extraction. > Others here will surely have proposals how to verify a whole pool tree. I can get the MD5sum for each file in the ISO and for each extracted file. I suppose it is a matter of meaningfully comaparing both lists. > > What will the output show if there is a problem with extraction? > > If it went bad on a DVD then you will probably see messages about SCSI > read errors. > If you read from an image file with damaged data file content but with > plausible meta data, then you might see no complaint at all. > > ------------------------------------------------------------------------ > > The second problem is that xorriso verifies its MD5 checksums only while > the files are still in the ISO image. A verification after extraction is not > yet possible. But it seems to be a useful feature. > > So for now you would verify the files in the ISO by e.g. > > xorriso -md5 on -indev "$the_iso" \ > -check_md5_r sorry / -- \ > | tee /tmp/report_of_mismatched_files This gives me: xorriso : NOTE : Loading ISO image tree from LBA 0 xorriso : UPDATE : 10164 nodes read in 1 seconds xorriso : NOTE : Detected El-Torito boot information which currently is set to be discarded Drive current: -indev 'debian-10.2.0-i386-DVD-1.iso' Media current: stdio file, overwriteable Media status : is written , is appendable Boot record : El Torito , MBR isohybrid cyl-align-on GPT APM Media summary: 1 session, 1939608 data blocks, 3788m data, 1603m free Volume id : 'Debian 10.2.0 i386 1' Not a single file with MD5 checksum was found. (There is no MD5 checksum array loaded.) and a file with the line Not a single file with MD5 checksum was found. (There is no MD5 checksum array loaded.) > You may list checksums and file paths in the ISO by > > xorriso -md5 on -indev "$the_iso" -find / -exec get_md5 -- >/tmp/md5sums The output is an empty file. xorriso : NOTE : Loading ISO image tree from LBA 0 xorriso : UPDATE : 10164 nodes read in 1 seconds xorriso : NOTE : Detected El-Torito boot information which currently is set to be discarded Drive current: -indev 'debian-10.2.0-i386-DVD-1.iso' Media current: stdio file, overwriteable Media status : is written , is appendable Boot record : El Torito , MBR isohybrid cyl-align-on GPT APM Media summary: 1 session, 1939608 data blocks, 3788m data, 1603m free Volume id : 'Debian 10.2.0 i386 1' If it is of consquence, the ISO was made by jigdo. -- Brian.
