bug-wget
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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


From: Tim Rühsen
Subject: Re: [Bug-wget] [PATCH] Support metalink:file elements with a "path/file" format
Date: Wed, 10 Aug 2016 11:30:12 +0200
User-agent: KMail/5.2.3 (Linux/4.6.0-1-amd64; KDE/5.23.0; x86_64; ; )

On Mittwoch, 10. August 2016 06:23:49 CEST Matthew White wrote:
> 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.

I thought about it when I awoke this night...

Let's assume the user types basically
        wget http://theserver.com/directory/archive.tgz
The server responds with a metalink file (or metalink within request header), 
wget retrieves the .meta file, which states the file name '/the/path/funny.sh'.

IMO, the (optional) directory options should apply to the URL path of the 
command line (http://theserver.com/directory/).

The downloaded/saved file name should be 'archive.tgz' - except with --trust-
server-names, here the file name should be 'funny.sh' (but still, any directory 
options should apply to the command line URL).

In general, I would recommend to tell the user when the filename from his URL 
and the file name in the Metalink info differ. If --trust-server-names was not 
given, we should give this as hint.

But we should *always* strip the path info from the metalink filename (/the/
path/funny.sh -> funny.sh), if appropriate (--trust-server-names is given).

If there are several files with the same name in the Metalink info and --trust-
server-names is given, we should apply the standard .1, .2, .3 ... extensions.

WDYT ?

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

Just push directly to your repo.

Regards, Tim

Attachment: signature.asc
Description: This is a digitally signed message part.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]