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From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "Carlo Marcelo Arenas Belón" <carenas@gmail.com>
Cc: git@vger.kernel.org, gitster@pobox.com, bagasdotme@gmail.com,
	phillip.wood123@gmail.com, "SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH v3 1/3] t: document regression git safe.directory when using sudo
Date: Thu, 5 May 2022 15:44:34 +0200 (CEST)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2205051439290.355@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20220503065442.95699-2-carenas@gmail.com>

[-- Attachment #1: Type: text/plain, Size: 5833 bytes --]

Hi Carlo,

On Mon, 2 May 2022, Carlo Marcelo Arenas Belón wrote:

> Originally reported after release of v2.35.2 (and other maint branches)
> for CVE-2022-24765 and blocking otherwise harmless commands that were
> done using sudo in a repository that was owned by the user.
>
> Add a new test script with very basic support to allow running git
> commands through sudo, so a reproduction could be implemented and that
> uses only `git status` as a proxy of the issue reported.
>
> Note that because of the way sudo interacts with the system, a much
> more complete integration with the test framework will require a lot
> more work and that was therefore intentionally punted for now.
>
> The current implementation requires the execution of a special cleanup
> function which should always be kept as the last "test" or otherwise
> the standard cleanup functions will fail because they can't remove
> the root owned directories that are used.  This also means that if
> failures are found while running the specifics of the failure might
> not be kept for further debugging and if the test was interrupted, it
> will be necessary to clean the working directory manually before
> restarting by running:
>
>   $ sudo rm -rf trash\ directory.t0034-root-safe-directory/
>
> The test file also uses at least one initial "setup" test that creates
> a parallel execution directory, while ignoring the repository created
> by the test framework, and special care should be taken when invoking
> commands through sudo, since the environment is otherwise independent
> from what the test framework expects.  Indeed `git status` was used
> as a proxy because it doesn't even require commits in the repository
> to work.
>
> A new SUDO prerequisite is provided that does some sanity checking
> to make sure the sudo command that will be used allows for passwordless
> execution as root and doesn't mess with git execution paths, but
> otherwise additional work will be required to ensure additional
> commands behave as expected and that will be addressed in a later patch.
>
> Most of those characteristics make this test mostly suitable only for
> CI, but it could be executed locally if special care is taken to provide
> for some of them in the local configuration and maybe making use of the
> sudo credential cache by first invoking sudo, entering your password if
> needed, and then invoking the test by doing:
>
>   $ IKNOWWHATIAMDOING=YES ./t0034-root-safe-directory.sh

Hmm. I would like to suggest that we can side-step all of these issues
(and the ones I outline below) by considering a similar approach to the
one Stolee took in t0033: use one or more `GIT_TEST_*` environment
variables to pretend the exact scenario we want to test for.

>
> Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
>  t/t0034-root-safe-directory.sh | 49 ++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100755 t/t0034-root-safe-directory.sh
>
> diff --git a/t/t0034-root-safe-directory.sh b/t/t0034-root-safe-directory.sh
> new file mode 100755
> index 00000000000..6dac7a05cfd
> --- /dev/null
> +++ b/t/t0034-root-safe-directory.sh
> @@ -0,0 +1,49 @@
> +#!/bin/sh
> +
> +test_description='verify safe.directory checks while running as root'
> +
> +. ./test-lib.sh
> +
> +if [ "$IKNOWWHATIAMDOING" != "YES" ]
> +then
> +	skip_all="You must set env var IKNOWWHATIAMDOING=YES in order to run this test"
> +	test_done
> +fi
> +
> +# this prerequisite should be added to all the tests, it not only prevents
> +# the test from failing but also warms up any authentication cache sudo
> +# might need to avoid asking for a password
> +test_lazy_prereq SUDO '
> +	sudo -n id -u >u &&
> +	id -u root >r &&
> +	test_cmp u r &&
> +	command -v git >u &&
> +	sudo command -v git >r &&

In my Ubuntu setup, `/bin/sh` is a symbolic link to `/bin/dash`, which
does not understand the `command`. It might make more sense to use `type`
here, but it is quite possible that `type git` uses a different output
format than `sudo type git` if they use different shells.

Another complication is that the `/etc/sudoers` I have over here specifies
a `secure_path`, which prevents the directory with the just-built `git`
executable from being left in `PATH`. I had to edit `/etc/sudoers` _and_
change the script to using `sudo -sE` to fix these woes.

It took me a good chunk of time to figure out how to run these tests, and
I will have to remember to revert the temporary edit of `/etc/sudoers`
file. This is definitely not something I plan on doing often, so I wonder
how these regression tests can guarantee that no regressions are
introduced if they are so hard to run ;-)

> +	test_cmp u r
> +'
> +
> +test_expect_success SUDO 'setup' '
> +	sudo rm -rf root &&
> +	mkdir -p root/r &&
> +	sudo chown root root &&
> +	(
> +		cd root/r &&
> +		git init
> +	)
> +'
> +
> +test_expect_failure SUDO 'sudo git status as original owner' '
> +	(
> +		cd root/r &&
> +		git status &&
> +		sudo git status
> +	)
> +'
> +
> +# this MUST be always the last test, if used more than once, the next
> +# test should do a full setup again.
> +test_expect_success SUDO 'cleanup' '
> +	sudo rm -rf root

This would be more canonical as `test_when_finished "sudo rm -rf root"` in
the preceding test cases.

But as I said above, I would prefer it if we could figure out a way to
pretend a specific scenario via `GIT_TEST_*`. That would ensure not only
that those tests are easy to run, but also that they run whenever the test
suite runs.

Thank you for working on this!
Dscho

> +'
> +
> +test_done
> --
> 2.36.0.352.g0cd7feaf86f
>
>

  parent reply	other threads:[~2022-05-05 13:46 UTC|newest]

Thread overview: 170+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-26 18:31 [RFC PATCH] git-compat-util: avoid failing dir ownership checks if running priviledged Carlo Marcelo Arenas Belón
2022-04-26 19:48 ` Derrick Stolee
2022-04-26 19:56   ` Junio C Hamano
2022-04-26 20:10     ` rsbecker
2022-04-26 20:45       ` Carlo Arenas
2022-04-26 21:10         ` Junio C Hamano
2022-04-26 20:12     ` Carlo Arenas
2022-04-26 20:26   ` Carlo Arenas
2022-04-29 16:16   ` Derrick Stolee
2022-04-27  0:05 ` [PATCH] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-04-27  9:33   ` Phillip Wood
2022-04-27 12:30     ` Phillip Wood
2022-04-27 14:15       ` rsbecker
2022-04-27 15:58       ` Carlo Arenas
2022-04-27 16:14         ` Phillip Wood
2022-04-27 18:54           ` Junio C Hamano
2022-04-27 20:59             ` Carlo Arenas
2022-04-27 21:09               ` rsbecker
2022-04-27 21:25               ` Junio C Hamano
2022-04-28 17:56             ` Phillip Wood
2022-04-27 15:38     ` Carlo Arenas
2022-04-27 15:50       ` rsbecker
2022-04-27 16:19       ` Junio C Hamano
2022-04-27 16:45         ` Carlo Arenas
2022-04-27 17:22         ` Phillip Wood
2022-04-27 17:49           ` rsbecker
2022-04-27 17:54             ` Carlo Arenas
2022-04-27 18:05               ` rsbecker
2022-04-27 18:11                 ` Carlo Arenas
2022-04-27 18:16                   ` rsbecker
2022-04-27 16:31       ` Phillip Wood
2022-04-27 16:54         ` Carlo Arenas
2022-04-27 17:28           ` Phillip Wood
2022-04-27 17:49             ` Carlo Arenas
2022-04-27 22:26   ` [RFC PATCH v2] " Carlo Marcelo Arenas Belón
2022-04-27 22:33     ` Junio C Hamano
2022-04-28  3:35     ` [PATCH 0/2] fix `sudo make install` regression in maint Carlo Marcelo Arenas Belón
2022-04-28  3:35       ` [PATCH 1/2] Documentation: explain how safe.directory works when running under sudo Carlo Marcelo Arenas Belón
2022-04-28  5:17         ` Junio C Hamano
2022-04-28  5:58           ` Carlo Arenas
2022-04-28  6:41             ` Junio C Hamano
2022-04-28  3:35       ` [PATCH 2/2] t: add tests for safe.directory when running with sudo Carlo Marcelo Arenas Belón
2022-04-28  5:34         ` Junio C Hamano
2022-04-28  4:57       ` [PATCH 0/2] fix `sudo make install` regression in maint Junio C Hamano
2022-04-28 10:58       ` [PATCH v2 0/3] " Carlo Marcelo Arenas Belón
2022-04-28 10:58         ` [PATCH v2 1/3] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-04-28 18:02           ` Phillip Wood
2022-04-28 18:57             ` Carlo Arenas
2022-04-28 10:58         ` [PATCH v2 2/3] Documentation: explain how safe.directory works when running under sudo Carlo Marcelo Arenas Belón
2022-04-30  6:17           ` Bagas Sanjaya
2022-04-30  6:39             ` Junio C Hamano
2022-04-30 14:15             ` Carlo Marcelo Arenas Belón
2022-04-28 10:58         ` [PATCH v2 3/3] t: add tests for safe.directory when running with sudo Carlo Marcelo Arenas Belón
2022-04-28 16:55           ` Junio C Hamano
2022-04-28 18:08             ` Phillip Wood
2022-04-28 18:12               ` Junio C Hamano
2022-05-06 17:50                 ` Carlo Arenas
2022-05-06 21:43                   ` Junio C Hamano
2022-05-06 22:57                     ` Carlo Arenas
2022-05-06 23:55                       ` Junio C Hamano
2022-05-07 11:57                         ` Carlo Marcelo Arenas Belón
2022-04-28 19:53             ` rsbecker
2022-04-28 20:22               ` Carlo Arenas
2022-04-28 20:43                 ` rsbecker
2022-04-28 20:51                   ` Junio C Hamano
2022-04-28 20:56                   ` Carlo Arenas
2022-04-28 21:55                     ` rsbecker
2022-04-28 22:21                       ` Junio C Hamano
2022-04-28 22:45                         ` rsbecker
2022-04-28 20:46                 ` Junio C Hamano
2022-04-28 20:32               ` Junio C Hamano
2022-04-28 20:40                 ` rsbecker
2022-04-28 20:48                 ` Carlo Arenas
2022-04-28 21:02             ` Carlo Arenas
2022-04-28 21:07               ` Junio C Hamano
2022-04-29  1:24                 ` Carlo Marcelo Arenas Belón
2022-04-29 18:50                   ` Junio C Hamano
2022-04-29 20:05                     ` Carlo Marcelo Arenas Belón
2022-05-02 18:39         ` [RFC PATCH v3 0/3] fix `sudo make install` regression in maint Carlo Marcelo Arenas Belón
2022-05-02 18:39           ` [RFC PATCH v3 1/3] t: document regression git safe.directory when using sudo Carlo Marcelo Arenas Belón
2022-05-02 21:35             ` Junio C Hamano
2022-05-02 23:07               ` Carlo Arenas
2022-05-02 18:39           ` [RFC PATCH v3 2/3] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-05-02 18:39           ` [RFC PATCH v3 3/3] t0034: enhance framework to allow testing more commands under sudo Carlo Marcelo Arenas Belón
2022-05-02 22:10             ` Junio C Hamano
2022-05-03  0:00               ` Carlo Arenas
2022-05-03  6:54         ` [PATCH v3 0/3] fix `sudo make install` regression in maint Carlo Marcelo Arenas Belón
2022-05-03  6:54           ` [PATCH v3 1/3] t: document regression git safe.directory when using sudo Carlo Marcelo Arenas Belón
2022-05-03 14:03             ` Phillip Wood
2022-05-03 15:56               ` Carlo Marcelo Arenas Belón
2022-05-04 11:15                 ` Phillip Wood
2022-05-04 13:02                   ` Carlo Arenas
2022-05-04 14:11                     ` Phillip Wood
2022-05-05 13:44             ` Johannes Schindelin [this message]
2022-05-05 14:34               ` Phillip Wood
2022-05-05 15:50               ` Junio C Hamano
2022-05-05 18:33               ` Junio C Hamano
2022-05-05 19:39                 ` Junio C Hamano
2022-05-06 21:03                   ` Carlo Arenas
2022-05-09  8:21                 ` Phillip Wood
2022-05-09 14:51                   ` Carlo Arenas
2022-05-09 15:18                     ` Phillip Wood
2022-05-09 16:01                   ` Junio C Hamano
2022-05-09 16:21                     ` Carlo Arenas
2022-05-06 17:39               ` Carlo Arenas
2022-05-03  6:54           ` [PATCH v3 2/3] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-05-05 14:01             ` Johannes Schindelin
2022-05-05 14:32               ` Phillip Wood
2022-05-06 19:15                 ` Carlo Arenas
2022-05-06 20:00                   ` Junio C Hamano
2022-05-06 20:22                     ` Carlo Arenas
2022-05-06 20:59                       ` Junio C Hamano
2022-05-06 21:40                         ` Carlo Arenas
2022-05-06 21:07                       ` rsbecker
2022-05-05 16:09               ` Junio C Hamano
2022-05-06 20:02               ` Carlo Arenas
2022-05-03  6:54           ` [PATCH v3 3/3] t0034: enhance framework to allow testing more commands under sudo Carlo Marcelo Arenas Belón
2022-05-03 14:12             ` Phillip Wood
2022-05-03 15:27               ` Junio C Hamano
2022-05-06 16:54               ` Carlo Arenas
2022-05-07 16:35           ` [RFC PATCH v4 0/3] fix `sudo make install` regression in maint Carlo Marcelo Arenas Belón
2022-05-07 16:35             ` [RFC PATCH v4 1/3] t: regression git needs safe.directory when using sudo Carlo Marcelo Arenas Belón
2022-05-07 16:35             ` [RFC PATCH v4 2/3] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-05-07 17:34               ` Junio C Hamano
2022-05-07 18:56                 ` Carlo Marcelo Arenas Belón
2022-05-09 16:54                   ` Junio C Hamano
2022-05-09 17:36                     ` rsbecker
2022-05-09 18:48                     ` Carlo Arenas
2022-05-09 19:16                       ` rsbecker
2022-05-09 19:41                       ` Junio C Hamano
2022-05-07 16:35             ` [RFC PATCH v4 3/3] t0034: add negative tests and allow git init to mostly work under sudo Carlo Marcelo Arenas Belón
2022-05-10 14:17             ` [RFC PATCH v4 0/3] fix `sudo make install` regression in maint Phillip Wood
2022-05-10 15:47               ` Carlo Arenas
2022-05-10 17:46             ` [PATCH " Carlo Marcelo Arenas Belón
2022-05-10 17:46               ` [PATCH v4 1/3] t: regression git needs safe.directory when using sudo Carlo Marcelo Arenas Belón
2022-05-10 22:10                 ` Junio C Hamano
2022-05-10 23:11                   ` Carlo Arenas
2022-05-10 23:44                     ` Junio C Hamano
2022-05-11  0:56                       ` Carlo Arenas
2022-05-11  1:11                         ` Junio C Hamano
2022-05-10 17:46               ` [PATCH v4 2/3] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-05-10 22:57                 ` Junio C Hamano
2022-05-11  7:34                   ` Carlo Arenas
2022-05-11 14:58                     ` Junio C Hamano
2022-05-10 17:46               ` [PATCH v4 3/3] t0034: add negative tests and allow git init to mostly work under sudo Carlo Marcelo Arenas Belón
2022-05-10 23:11                 ` Junio C Hamano
2022-05-10 23:25                   ` Junio C Hamano
2022-05-11 14:04                   ` Carlo Arenas
2022-05-11 15:29                     ` Junio C Hamano
2022-05-13  1:00               ` [PATCH v5 0/4] fix `sudo make install` regression in maint Carlo Marcelo Arenas Belón
2022-05-13  1:00                 ` [PATCH v5 1/4] t: regression git needs safe.directory when using sudo Carlo Marcelo Arenas Belón
2022-06-03 12:12                   ` SZEDER Gábor
2022-05-13  1:00                 ` [PATCH v5 2/4] git-compat-util: avoid failing dir ownership checks if running privileged Carlo Marcelo Arenas Belón
2022-06-03 11:05                   ` SZEDER Gábor
2022-06-03 16:54                     ` Junio C Hamano
2022-06-03 17:34                       ` SZEDER Gábor
2022-05-13  1:00                 ` [PATCH v5 3/4] t0034: add negative tests and allow git init to mostly work under sudo Carlo Marcelo Arenas Belón
2022-05-13  1:20                   ` Junio C Hamano
2022-05-14 14:36                     ` Carlo Arenas
2022-05-15 16:54                       ` Junio C Hamano
2022-05-15 19:21                         ` Carlo Arenas
2022-05-16  5:27                           ` Junio C Hamano
2022-05-16 13:07                             ` Carlo Marcelo Arenas Belón
2022-05-16 16:25                               ` Junio C Hamano
2022-05-13  1:00                 ` [PATCH v5 4/4] git-compat-util: allow root to access both SUDO_UID and root owned Carlo Marcelo Arenas Belón
2022-06-15 14:02                   ` Johannes Schindelin
2022-06-17 14:26                     ` Carlo Arenas
2022-06-17 16:00                       ` Junio C Hamano
2022-06-17 20:23                   ` [PATCH v6] " Carlo Marcelo Arenas Belón
2022-06-17 21:02                     ` Junio C Hamano

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