Re: [Bug-wget] [PATCH] Support metalink:file elements with a "path/file" format

[Matthew White]

On Tue, 09 Aug 2016 21:25:16 +0200
Tim Rühsen <address@hidden> wrote:

> On Freitag, 5. August 2016 20:25:06 CEST Matthew White wrote:
> > On Thu, 04 Aug 2016 16:47:18 +0200
> > 
> > Tim Ruehsen <address@hidden> wrote:
> > > On Wednesday, August 3, 2016 1:46:56 PM CEST Matthew White wrote:
> > > > On Tue, 02 Aug 2016 11:27:08 +0200
> > > > 
> > > > Tim Ruehsen <address@hidden> wrote:
> > > > > On Tuesday, August 2, 2016 10:06:42 AM CEST Matthew White wrote:
> > > > > > On Sat, 30 Jul 2016 21:23:56 +0200
> > > > > > 
> > > > > > Matthew White <address@hidden> wrote:
> > > > > > > Hello!
> > > > > > > 
> > > > > > > I noticed that wget doesn't use the metalink:file element as the
> > > > > > > RFC5854
> > > > > > > suggests.
> > > > > > > 
> > > > > > > https://tools.ietf.org/html/rfc5854#section-4.1.2.1
> > > > > > > 
> > > > > > > The RFC5854 specifies that the metalink:file could have a
> > > > > > > "path/file"
> > > > > > > format. In this case wget should create the "path" tree and save
> > > > > > > the
> > > > > > > file
> > > > > > > as "path/file", but it doesn't. Instead wget saves the file in the
> > > > > > > working directory.
> > > > > > > 
> > > > > > > e.g. <file name="dirA/dirB/file.gz">
> > > > > > > 
> > > > > > > With this patch wget conforms to the RFC5854.
> > > > > > > 
> > > > > > > I made this patch working on the following branch:
> > > > > > > master (latest 20cac2c5ab3d63aacfba35fb10878a2d490e2377)
> > > > > > > git://git.savannah.gnu.org/wget.git
> > > > > > > 
> > > > > > > Let me know if this helps.
> > > > > > 
> > > > > > Hi,
> > > > > > 
> > > > > > After the suggestions of Tim, I fixed the patch (nice! fix the
> > > > > > fix...).
> > > > > > So,
> > > > > > scratch the previous patch and use this one instead.
> > > > > > 
> > > > > > The function concat_strings() replaces the combination of malloc(),
> > > > > > strlen(), and strcpy(). (Thanks Tim.)
> > > > > 
> > > > > In this special case (just one string to clone), please use xstrdup().
> > > > > That is much less overhead.
> > > > > 
> > > > > > The description now follows the style of the other patches. (Thanks
> > > > > > again
> > > > > > Tim!)
> > > > > > 
> > > > > > You may consider this patch a Bugfix:
> > > > > > * src/utils.c (unique_create, fopen_excl): cannot create a directory
> > > > > > tree
> > > > > > like "path/file".
> > > > > > 
> > > > > > The problem is that fopen_excl() doesn't create non-existing
> > > > > > directories.
> > > > > > What do you suggest?
> > > > > 
> > > > > IMO, saving metalink files should work 'as usual and expected'. That
> > > > > means, all the directory options should apply (see man wget /
> > > > > Directory
> > > > > Options). We also have to deal with 'escaping' file name sequences
> > > > > like
> > > > > ../ etc.
> > > > > Not to forget character set conversions.
> > > > > 
> > > > > What about cases where you download https://myserver/file.tgz, and in
> > > > > the
> > > > > metalink file 'name' is set to 'xyz.doc' ? IMO, we should keep
> > > > > file.tgz,
> > > > > except the user stated --trust-server-names.
> > > > > 
> > > > > Maybe we should set up a a metalink document where we define how
> > > > > everything
> > > > > should work including corner cases. Next step would be to set up
> > > > > appropriate tests and fix the wget metalink code to survive the tests.
> > > > > 
> > > > > > Can we make this patch obsolete?
> > > > > 
> > > > > Basically yes.
> > > > > But we see, there is still much to do around metalink ... but most of
> > > > > the
> > > > > needed code is already there. Most work will be the definition and the
> > > > > tests.
> > > > > 
> > > > > Regards, Tim
> > > > 
> > > > Changed to use xstrdup(), new patch attached.
> > > 
> > > I already mentioned, that taking the metalink filename pulls in a security
> > > issue. It might escape the current directory with a relative or absolute
> > > path.
> > Actually, wget aborts if something like "../path/file" is found as
> > metalink:file name (see attached document as patch). The same goes for
> > "./path/file" and "/path/file".
> > > You might just take the file name without path, but only if the the option
> > > -- trust-server-names has been set.
> > > 
> > > Tim
> > 
> > Hi Tim,
> > 
> > I got your PM, did you get mine (I had an email server problem)?
> > 
> > I wrote a draft Metalink.README trying to explain the current interaction
> > between "Directory Options" and the option '--include-metalink=file' on the
> > command line.
> > 
> > I attach the Metalink.README here as a patch.
> > 
> > Can you confirm my findings? (Don't rush)
> 
> I created a new upstream branch 'metalink' where we can put further work for 
> testing. I included your README as doc/metalink.txt and also added two tests 
> for '../File1' and '/File1', which currently fail (the tests expect 'File1' 
> to 
> be written). 
> 
> You can't push there, but maybe you clone it (e.g. to Gitlab, Github or 
> elsewhere) and push your changes to that repo. So I can directly merge from 
> there (and you could then merge from upstream 'metalink').
> 
> I still didn't find time to think about the Metalink file naming details...
> 
> Regards, Tim

Hi Tim,

I forked https://github.com/mirror/wget.

As you suggest, now I'm pushing to the metalink branch on my repo:
https://github.com/mehw/wget/tree/metalink

As you said, escaping relative and absolute paths from metalink:file names, 
except when the option --trust-server-names is used, seems a good idea. I'll 
work on this ASAP.

Shall I create a new branch or push directly to metalink in my repo?

Thanks for the tests.

Later,
Matthew

-- 
Matthew White <address@hidden>

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