[Yum-devel] [PATCH 2/2] Fix md5 == abort() code path, only generate/trust sha2+ for metalink=>repomd

[James Antill]

On Tue, 2009-12-08 at 11:24 -0500, Seth Vidal wrote:
> 
> On Mon, 7 Dec 2009, James Antill wrote:
> 
> > ---
> > yum/metalink.py     |    1 +
> > yum/repoMDObject.py |    5 +++--
> > yum/yumRepo.py      |   12 +++---------
> > 3 files changed, 7 insertions(+), 11 deletions(-)
> >
> > diff --git a/yum/metalink.py b/yum/metalink.py
> > index c7f5f83..24da633 100755
> > --- a/yum/metalink.py
> > +++ b/yum/metalink.py
> > @@ -55,6 +55,7 @@ class MetaLinkFile:
> >     """ Parse the file metadata out of a metalink file. """
> >
> >     def __init__(self, elem):
> > +        # We aren't "using" any of these, just storing them.
> >         chksums = set(["md5", 'sha1', 'sha256', 'sha512'])
> >
> >         for celem in elem:
> > diff --git a/yum/repoMDObject.py b/yum/repoMDObject.py
> > index 9f70f1d..2931816 100755
> > --- a/yum/repoMDObject.py
> > +++ b/yum/repoMDObject.py
> > @@ -94,8 +94,9 @@ class RepoMD:
> >         else:
> >             # srcfile is a file object
> >             infile = srcfile
> > -
> > -        infile = AutoFileChecksums(infile, ['md5', 'sha1', 'sha256'],
> > +
> > +        # We trust any of these to mean the repomd.xml is valid.
> > +        infile = AutoFileChecksums(infile, ['sha256', 'sha512'],
> >                                    ignore_missing=True)
> >         parser = iterparse(infile)
> >
> > diff --git a/yum/yumRepo.py b/yum/yumRepo.py
> > index 765a595..b97f05a 100644
> > --- a/yum/yumRepo.py
> > +++ b/yum/yumRepo.py
> > @@ -1145,22 +1145,16 @@ class YumRepository(Repository, config.RepoConf):
> >         if repoXML.length != repomd.size:
> >             return False
> >
> > -        #  MirrorManager isn't generating sha256 yet, and we should probably
> > -        # not require all of the checksums we produce.
> > -        done = set()
> >         for checksum in repoXML.checksums:
> >             if checksum not in repomd.chksums:
> >                 continue
> >
> >             if repoXML.checksums[checksum] != repomd.chksums[checksum]:
> >                 return False
> > -            done.add(checksum)
> >
> > -        #  Only allow approved checksums, might want to not "approve" of
> > -        # sha1/md5
> > -        for checksum in ('sha512', 'sha256', 'sha1', 'md5'):
> > -            if checksum in done:
> > -                return True
> > +            #  If we don't trust the checksum, then don't generate it in
> > +            # repoMDObject().
> > +            return True
> >
> >         return False
> 
> Not tested this yet - but does this implicitly mean we need to do a: 
> Requires: python-hashlib if we want that version to be usable on python 
> 2.4?

 Yeh, we could keep 'sha1' to make it happy but I'm not sure people will
like just trusting 'sha1'.
 Or we could hide the raise() somehow, so you could still use it on
2.4.x without hashlib (but you won't have checksums for metalink to
check against).