RPMs corrupted

[Tony Nelson]

At 10:58 AM +0000 5/8/06, Per I. Mathisen wrote:
>I have a very strange problem.
>
>RPMs become corrupted when downloading them with ftp or http under Fedora
>Core 4 and 5 (different partitions, same box). They are not corrupte when
>downloading with http under Windows XP (also same box). I have tried many
>mirrors, including download.fedora.redhat.com
>
>The RPMs fail the rpm -K check and their md5sum is wrong. Only some RPMs
>fail, however. Some are always good, some are sometimes good, and some
>always fail. I cannot find a clear pattern.
>
>However, the RPMs are fine if I download them with scp, and also seem to
>download fine if I gzip or rename them to something not with the .rpm
>suffix.
>
>The Core 5 partition is a new, clean install. The Core4 partition has
>not been updated in quite a while, but used to update fine earlier.
>
>Doing cmp -l on the RPMs that are corrupted against good versions shows
>one of the two bytes 317 377 or 337 377 as differences at various
>positions in the RPMs. Usually each corrupt RPM only has one of these, and
>always at the same position for the same RPM through multiple redownloads.
>In one case I noticed one RPM getting an additional byte pair after a
>redownload but that was gone at the next redownload.
>
>It looks like this:
>
>   [perrin at localhost ~]$ rpm -K procps-3.2.6-3.3.i386.rpm
>   procps-3.2.6-3.3.i386.rpm: (SHA1) DSA SHA1 MD5 GPG NOT OK
>
>   [perrin at localhost new]$ cmp -l procps-3.2.6-3.3.i386.rpm
>   /mnt/l/rpms/procps-3.2.6-3.3.i386.rpm
>     5333 317 377
>
>   [perrin at localhost new]$ cmp -l gedit-2.14.2-1.fc5.1.i386.rpm
>   /mnt/l/rpms/gedit-2.14.2-1.fc5.1.i386.rpm
>     22089 337 377
>     22453 337 377
>   2790177 337 377
>
>So far I've this is what I have tried after helpful suggestions from
>people in #fedora on freenode:
>  - memtest86 for several hours
>  - changing MTU on my network interface
>  - rebooting my ADSL router
>  - checking ifconfig for errors or collisions
>  - rpm -Va and a rootkit detector
>  - rpm --import /etc/pki/rpm-gpg/*
>
>None of this fixed the problem or showed anything suspicious.
>
>I tried to unpack the RPMs using rpm2cpio to find what files
>were changed, but found no changes in files in the checked RPMs.
>
>Any ideas on what else I can try to figure this out, please? Thanks a lot
>for any help.

Can you try a different ADSL modem, or can you try dial-up?  Possibly this
is a problem with certain bit patterns on the ADSL modem.

Note that TCP checksums are not particularly robust, so some bad packets
may slip through.  That's one reason for the overall MD5 checksum.
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