From access user in phoronix article:

Seems like the dd options are the problem. If you use ibs instead of bs
at all places in the dd wrapper it works as expected with uutils too.
bs= should set both ibs and obs.

Something strange going on with coreutils too in this case as it reports
the wrong amount of bytes read.

Code:
❯ sh -c '(dd ibs=20487 skip=1 count=1; dd bs=4194304 count=1; dd bs=2441216 
count=1) < VBoxLinuxAdditions.run | md5sum'
1+0 records in
40+1 records out
20487 bytes (20 kB, 20 KiB) copied, 6,6885e-05 s, 306 MB/s
1+0 records in
1+0 records out
4194304 bytes (4,2 MB, 4,0 MiB) copied, 0,0119912 s, 350 MB/s
0+1 records in
0+1 records out
2420729 bytes (2,4 MB, 2,3 MiB) copied, 0,00790668 s, 306 MB/s
201ccc47587bb1c28745279e8b7fdd30  -
The last one should be 2441216 bytes. Changing the first skip to instead 
writing to /dev/null produces the correct value

Code:
❯ sh -c '(dd ibs=20487 of=/dev/null count=1; dd bs=4194304 count=1; dd 
bs=2441216 count=1) < VBoxLinuxAdditions.run | md5sum'
1+0 records in
40+1 records out
20487 bytes (20 kB, 20 KiB) copied, 8,5465e-05 s, 240 MB/s
1+0 records in
1+0 records out
4194304 bytes (4,2 MB, 4,0 MiB) copied, 0,011503 s, 365 MB/s
1+0 records in
1+0 records out
2441216 bytes (2,4 MB, 2,3 MiB) copied, 0,00491868 s, 496 MB/s
201ccc47587bb1c28745279e8b7fdd30  -
And finally uutils with ibs instead of bs for the last block

Code:
❯ sh -c '(./coreutils dd ibs=20487 skip=1 count=1; ./coreutils dd bs=4194304 
count=1; ./coreutils dd ibs=2441216 count=1) < VBoxLinuxAdditions.run | 
./coreutils md5sum'
1+0 records in
40+1 records out
20487 bytes (20 kB, 20 KiB) copied, 0.00441375 s, 5.1 MB/s
1+0 records in
1+0 records out
4194304 bytes (4.2 MB, 4.0 MiB) copied, 0.0127932 s, 350 MB/s
0+1 records in
4727+1 records out
2420729 bytes (2.4 MB, 2.3 MiB) copied, 0.0062951 s, 403 MB/s
201ccc47587bb1c28745279e8b7fdd30  -


Last edited by access; 26 September 2025, 01:25 PM.

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https://bugs.launchpad.net/bugs/2125535

Title:
  makeself archive failing md5sum validation

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