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

[Tim Ruehsen]

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.

You might just take the file name without path, but only if the the option --
trust-server-names has been set.

Tim

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