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From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org
Subject: Re: [PATCH v2 4/4] apply: do not touch a file beyond a symbolic link
Date: Tue, 03 Feb 2015 13:01:06 -0800	[thread overview]
Message-ID: <xmqqy4oepv59.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20150203011139.GC31946@peff.net> (Jeff King's message of "Mon, 2 Feb 2015 20:11:40 -0500")

Jeff King <peff@peff•net> writes:

> Here's the test addition I came up with, because it didn't look like we
> were covering this case. 

Thanks.

> diff --git a/t/t4122-apply-symlink-inside.sh b/t/t4122-apply-symlink-inside.sh
> index 942c5cb..fbba8dd 100755
> --- a/t/t4122-apply-symlink-inside.sh
> +++ b/t/t4122-apply-symlink-inside.sh
> @@ -89,6 +89,7 @@ test_expect_success SYMLINKS 'do not follow symbolic link (setup)' '
>  	rm -fr arch/x86_64/dir &&
>  
>  	cat add_symlink.patch add_file.patch >patch &&
> +	cat add_symlink.patch del_file.patch >tricky_del &&

This new patch

 (1) creates a symlink arch/x86_64/dir pointing at ../i386/dir
 (2) deletes arch/x86_64/dir/file

It can be a valid patch to be applied to a tree where arch/x86_64/dir/file
is in the index (either as a regular file, a symlink, or even a submodule)
and nothing else is in arch/x86_64/dir directory.


> @@ -112,6 +113,20 @@ test_expect_success SYMLINKS 'do not follow symbolic link (same input)' '
>  	test_i18ngrep "beyond a symbolic link" error-ct &&
>  	test_must_fail git ls-files --error-unmatch arch/x86_64/dir &&
>  	test_must_fail git ls-files --error-unmatch arch/i386/dir
> +
> +	>arch/i386/dir/file &&
> +	git add arch/i386/dir/file &&

At this point, the target of the patch application has:

	arch/i386/boot/Makefile
	arch/i386/dir/file
	arch/x86_64/boot/Makefile

all of which are regular files.  The index and the working tree
match.

> +	test_must_fail git apply tricky_del &&

The reason why this does not apply has nothing to do with the topic
of this series, I think.  It wants to delete arch/x86_64/dir/file,
which does not exist in the target, and the patch is rejected.

It is a good test to make sure that we do not "incrementally" apply
and get fooled by arch/x86_64/dir that will become a symbolic link,
making arch/x86_64/dir/file to appear as arch/i386/dir/file that
does exist in the preimage.

> +	test_path_is_file arch/i386/dir/file &&

When we reject the entire patch, we do so without touching the
outside world, of course ;-), which is good.

> +	test_must_fail git apply --index tricky_del &&
> +	test_path_is_file arch/i386/dir/file &&
> +	test_must_fail git ls-files --error-unmatch arch/x86_64/dir &&
> +	git ls-files --error-unmatch arch/i386/dir &&
> +
> +	test_must_fail git apply --cached tricky_del &&
> +	test_must_fail git ls-files --error-unmatch arch/x86_64/dir &&
> +	git ls-files --error-unmatch arch/i386/dir
>  '

In both of the above, "git apply" rejects its input for the same
reason.  The file it wants to remove does not exist in the target.

>  test_expect_success SYMLINKS 'do not follow symbolic link (existing)' '
> @@ -125,6 +140,7 @@ test_expect_success SYMLINKS 'do not follow symbolic link (existing)' '
>  	test_i18ngrep "beyond a symbolic link" error-wt-add &&
>  	test_path_is_missing arch/i386/dir/file &&
>  
> +	mkdir arch/i386/dir &&

Thanks for spotting this one ;-)

>  	>arch/i386/dir/file &&
>  	test_must_fail git apply del_file.patch 2>error-wt-del &&

del_file.patch wants to remove arch/x86_64/dir/file, and arch/x86_64/dir
is a symbolic link to ../i386/dir in the target at this point, so it
is trying to delete beyond the symbolic link, which gets rejected by
this series.  Good.

>  	test_i18ngrep "beyond a symbolic link" error-wt-del &&

  parent reply	other threads:[~2015-02-03 21:01 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-02 23:27 [PATCH v2 0/4] "git apply" safety Junio C Hamano
2015-02-02 23:27 ` [PATCH v2 1/4] apply: reject input that touches outside $cwd Junio C Hamano
2015-02-03  0:45   ` Jeff King
2015-02-03  0:50   ` Jeff King
2015-02-03 20:23     ` Junio C Hamano
2015-02-03 21:01       ` Jeff King
2015-02-03 21:23         ` Junio C Hamano
2015-02-03 21:24           ` Jeff King
2015-02-03 21:40             ` Junio C Hamano
2015-02-03 21:50               ` Jeff King
2015-02-03 22:11                 ` Junio C Hamano
2015-02-03  5:56   ` Torsten Bögershausen
2015-02-02 23:27 ` [PATCH v2 2/4] apply: do not read from the filesystem under --index Junio C Hamano
2015-02-02 23:27 ` [PATCH v2 3/4] apply: do not read from beyond a symbolic link Junio C Hamano
2015-02-03  0:08   ` Stefan Beller
2015-02-03 19:37     ` Junio C Hamano
2015-02-03 19:44       ` Stefan Beller
2015-02-03 20:31         ` Junio C Hamano
2015-02-02 23:27 ` [PATCH v2 4/4] apply: do not touch a file " Junio C Hamano
2015-02-03  1:11   ` Jeff King
2015-02-03  1:56     ` Junio C Hamano
2015-02-03  2:04       ` Jeff King
2015-02-03 21:01     ` Junio C Hamano [this message]
2015-02-03 23:40       ` Eric Sunshine
2015-02-04  0:44 ` [PATCH v3 0/4] "git apply" safety Junio C Hamano
2015-02-04  0:44   ` [PATCH v3 1/4] apply: reject input that touches outside the working area Junio C Hamano
2015-02-04  0:44   ` [PATCH v3 2/4] apply: do not read from the filesystem under --index Junio C Hamano
2015-02-04  0:44   ` [PATCH v3 3/4] apply: do not read from beyond a symbolic link Junio C Hamano
2015-02-04  0:44   ` [PATCH v3 4/4] apply: do not touch a file " Junio C Hamano
2015-02-10 22:36   ` [PATCH v4 0/4] "git apply" safety Junio C Hamano
2015-02-10 22:36     ` [PATCH v4 1/4] apply: reject input that touches outside the working area Junio C Hamano
2015-02-10 22:36     ` [PATCH v4 2/4] apply: do not read from the filesystem under --index Junio C Hamano
2015-02-10 22:36     ` [PATCH v4 3/4] apply: do not read from beyond a symbolic link Junio C Hamano
2015-02-10 22:36     ` [PATCH v4 4/4] apply: do not touch a file " Junio C Hamano

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