From: Junio C Hamano <gitster@pobox.com>
To: Brandon Williams <bmwill@google.com>
Cc: git@vger.kernel.org, j6t@kdbg.org, sbeller@google.com,
e@80x24.org, jrnieder@gmail.com, peff@peff.net
Subject: Re: [PATCH v8 2/2] run-command: restrict PATH search to executable files
Date: Tue, 25 Apr 2017 18:44:44 -0700 [thread overview]
Message-ID: <xmqqzif4t01f.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170425234700.194277-2-bmwill@google.com> (Brandon Williams's message of "Tue, 25 Apr 2017 16:47:00 -0700")
Brandon Williams <bmwill@google.com> writes:
> In some situations run-command will incorrectly try (and fail) to
> execute a directory instead of an executable file. This was observed by
> having a directory called "ssh" in $PATH before the real ssh and trying
> to use ssh protoccol, reslting in the following:
>
> $ git ls-remote ssh://url
> fatal: cannot exec 'ssh': Permission denied
>
> It ends up being worse and run-command will even try to execute a
> non-executable file if it preceeds the executable version of a file on
> the PATH. For example, if PATH=~/bin1:~/bin2:~/bin3 and there exists a
> directory 'git-hello' in 'bin1', a non-executable file 'git-hello' in
> bin2 and an executable file 'git-hello' (which prints "Hello World!") in
> bin3 the following will occur:
>
> $ git hello
> fatal: cannot exec 'git-hello': Permission denied
>
> This is due to only checking 'access()' when locating an executable in
> PATH, which doesn't distinguish between files and directories. Instead
> use 'is_executable()' which check that the path is to a regular,
> executable file. Now run-command won't try to execute the directory or
> non-executable file 'git-hello':
>
> $ git hello
> Hello World!
Could you add a line after this example, that says something like
"which matches what execvp() would have done with a request to
execute git-hello with such a $PATH."
That is because it can be argued that bin1/git-hello should be found
and get complaint "not an executable file", or that bin1/git-hello
should be skipped but bin2/git-hello should be found and get
complaint "not an executable file", both to help the user diagnose
and fix the broken $PATH (or director contents). It is the easiest
to justify why we chose this other definition to skip both git-hello
in bin1 and bin2 if that is an established existing practice---we
can say "sure, what you propose also may make sense, but we match
what execvp(3) does".
The patch text looks good.
Thanks.
next prev parent reply other threads:[~2017-04-26 1:44 UTC|newest]
Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-10 23:49 [PATCH 0/5] forking and threading Brandon Williams
2017-04-10 23:49 ` [PATCH 1/5] run-command: convert sane_execvp to sane_execvpe Brandon Williams
2017-04-12 19:22 ` Brandon Williams
2017-04-10 23:49 ` [PATCH 2/5] run-command: prepare argv before forking Brandon Williams
2017-04-10 23:49 ` [PATCH 3/5] run-command: allocate child_err " Brandon Williams
2017-04-10 23:49 ` [PATCH 4/5] run-command: prepare child environment " Brandon Williams
2017-04-11 0:58 ` Jonathan Nieder
2017-04-11 17:27 ` Brandon Williams
2017-04-11 17:30 ` Jonathan Nieder
2017-04-10 23:49 ` [PATCH 5/5] run-command: add note about forking and threading Brandon Williams
2017-04-11 0:26 ` Jonathan Nieder
2017-04-11 0:53 ` Eric Wong
2017-04-11 17:33 ` Jonathan Nieder
2017-04-11 17:34 ` Brandon Williams
2017-04-11 17:40 ` Eric Wong
2017-04-11 7:05 ` [PATCH 6/5] run-command: avoid potential dangers in forked child Eric Wong
2017-04-11 16:29 ` Brandon Williams
2017-04-11 16:59 ` Eric Wong
2017-04-11 17:17 ` Brandon Williams
2017-04-11 17:37 ` [PATCH 0/5] forking and threading Jonathan Nieder
2017-04-11 17:54 ` Brandon Williams
2017-04-13 18:32 ` [PATCH v2 0/6] " Brandon Williams
2017-04-13 18:32 ` [PATCH v2 1/6] t5550: use write_script to generate post-update hook Brandon Williams
2017-04-13 20:43 ` Jonathan Nieder
2017-04-13 20:59 ` Eric Wong
2017-04-13 21:35 ` Brandon Williams
2017-04-13 21:39 ` Eric Wong
2017-04-13 18:32 ` [PATCH v2 2/6] run-command: prepare command before forking Brandon Williams
2017-04-13 21:14 ` Jonathan Nieder
2017-04-13 22:41 ` Brandon Williams
2017-04-13 18:32 ` [PATCH v2 3/6] run-command: prepare child environment " Brandon Williams
2017-04-13 18:32 ` [PATCH v2 4/6] run-command: don't die in child when duping /dev/null Brandon Williams
2017-04-13 19:29 ` Eric Wong
2017-04-13 19:43 ` Brandon Williams
2017-04-13 18:32 ` [PATCH v2 5/6] run-command: eliminate calls to error handling functions in child Brandon Williams
2017-04-13 18:32 ` [PATCH v2 6/6] run-command: add note about forking and threading Brandon Williams
2017-04-13 20:50 ` [PATCH v2 0/6] " Jonathan Nieder
2017-04-13 23:44 ` Brandon Williams
2017-04-13 21:14 ` [PATCH 7/6] run-command: block signals between fork and execve Eric Wong
2017-04-13 23:37 ` Brandon Williams
2017-04-14 2:42 ` Brandon Williams
2017-04-14 5:26 ` Eric Wong
2017-04-14 5:35 ` Eric Wong
2017-04-14 16:58 ` [PATCH v3 00/10] forking and threading Brandon Williams
2017-04-14 16:58 ` [PATCH v3 01/10] t5550: use write_script to generate post-update hook Brandon Williams
2017-04-14 16:58 ` [PATCH v3 02/10] t0061: run_command executes scripts without a #! line Brandon Williams
2017-04-14 16:58 ` [PATCH v3 03/10] run-command: prepare command before forking Brandon Williams
2017-04-14 16:58 ` [PATCH v3 04/10] run-command: use the async-signal-safe execv instead of execvp Brandon Williams
2017-04-14 16:58 ` [PATCH v3 05/10] run-command: prepare child environment before forking Brandon Williams
2017-04-14 16:58 ` [PATCH v3 06/10] run-command: don't die in child when duping /dev/null Brandon Williams
2017-04-14 19:38 ` Eric Wong
2017-04-14 20:19 ` Brandon Williams
2017-04-14 16:58 ` [PATCH v3 07/10] run-command: eliminate calls to error handling functions in child Brandon Williams
2017-04-14 18:50 ` Eric Wong
2017-04-14 20:22 ` Brandon Williams
2017-04-14 16:59 ` [PATCH v3 08/10] run-command: handle dup2 and close errors " Brandon Williams
2017-04-14 16:59 ` [PATCH v3 09/10] run-command: add note about forking and threading Brandon Williams
2017-04-14 16:59 ` [PATCH v3 10/10] run-command: block signals between fork and execve Brandon Williams
2017-04-14 20:24 ` Brandon Williams
2017-04-14 21:35 ` Eric Wong
2017-04-17 22:08 ` [PATCH v4 00/10] forking and threading Brandon Williams
2017-04-17 22:08 ` [PATCH v4 01/10] t5550: use write_script to generate post-update hook Brandon Williams
2017-04-17 22:08 ` [PATCH v4 02/10] t0061: run_command executes scripts without a #! line Brandon Williams
2017-04-17 22:08 ` [PATCH v4 03/10] run-command: prepare command before forking Brandon Williams
2017-04-17 22:08 ` [PATCH v4 04/10] run-command: use the async-signal-safe execv instead of execvp Brandon Williams
2017-04-17 22:08 ` [PATCH v4 05/10] run-command: prepare child environment before forking Brandon Williams
2017-04-18 0:26 ` Eric Wong
2017-04-18 21:02 ` Brandon Williams
2017-04-17 22:08 ` [PATCH v4 06/10] run-command: don't die in child when duping /dev/null Brandon Williams
2017-04-17 22:08 ` [PATCH v4 07/10] run-command: eliminate calls to error handling functions in child Brandon Williams
2017-04-17 22:08 ` [PATCH v4 08/10] run-command: handle dup2 and close errors " Brandon Williams
2017-04-17 22:08 ` [PATCH v4 09/10] run-command: add note about forking and threading Brandon Williams
2017-04-17 22:08 ` [PATCH v4 10/10] run-command: block signals between fork and execve Brandon Williams
2017-04-18 23:17 ` [PATCH v5 00/11] forking and threading Brandon Williams
2017-04-18 23:17 ` [PATCH v5 01/11] t5550: use write_script to generate post-update hook Brandon Williams
2017-04-18 23:17 ` [PATCH v5 02/11] t0061: run_command executes scripts without a #! line Brandon Williams
2017-04-19 5:43 ` Johannes Sixt
2017-04-19 6:21 ` Johannes Sixt
2017-04-19 15:56 ` Brandon Williams
2017-04-19 18:18 ` Johannes Sixt
2017-04-20 10:47 ` Johannes Schindelin
2017-04-20 17:02 ` Brandon Williams
2017-04-20 20:24 ` Johannes Schindelin
2017-04-20 20:49 ` Brandon Williams
2017-04-18 23:17 ` [PATCH v5 03/11] run-command: prepare command before forking Brandon Williams
2017-04-18 23:17 ` [PATCH v5 04/11] run-command: use the async-signal-safe execv instead of execvp Brandon Williams
2017-04-18 23:17 ` [PATCH v5 05/11] string-list: add string_list_remove function Brandon Williams
2017-04-18 23:31 ` Stefan Beller
2017-04-18 23:36 ` Brandon Williams
2017-04-18 23:40 ` Stefan Beller
2017-04-18 23:18 ` [PATCH v5 06/11] run-command: prepare child environment before forking Brandon Williams
2017-04-18 23:18 ` [PATCH v5 07/11] run-command: don't die in child when duping /dev/null Brandon Williams
2017-04-18 23:18 ` [PATCH v5 08/11] run-command: eliminate calls to error handling functions in child Brandon Williams
2017-04-18 23:18 ` [PATCH v5 09/11] run-command: handle dup2 and close errors " Brandon Williams
2017-04-18 23:18 ` [PATCH v5 10/11] run-command: add note about forking and threading Brandon Williams
2017-04-18 23:18 ` [PATCH v5 11/11] run-command: block signals between fork and execve Brandon Williams
2017-04-19 6:00 ` Johannes Sixt
2017-04-19 7:48 ` Eric Wong
2017-04-19 16:10 ` Brandon Williams
2017-04-19 23:13 ` [PATCH v6 00/11] forking and threading Brandon Williams
2017-04-19 23:13 ` [PATCH v6 01/11] t5550: use write_script to generate post-update hook Brandon Williams
2017-04-19 23:13 ` [PATCH v6 02/11] t0061: run_command executes scripts without a #! line Brandon Williams
2017-04-20 10:49 ` Johannes Schindelin
2017-04-20 16:58 ` Brandon Williams
2017-04-19 23:13 ` [PATCH v6 03/11] run-command: prepare command before forking Brandon Williams
2017-04-19 23:13 ` [PATCH v6 04/11] run-command: use the async-signal-safe execv instead of execvp Brandon Williams
2017-05-17 2:15 ` Junio C Hamano
2017-05-17 2:26 ` Jeff King
2017-05-17 2:28 ` Jeff King
2017-05-17 3:41 ` Junio C Hamano
2017-05-17 14:52 ` Brandon Williams
2017-04-19 23:13 ` [PATCH v6 05/11] string-list: add string_list_remove function Brandon Williams
2017-04-19 23:13 ` [PATCH v6 06/11] run-command: prepare child environment before forking Brandon Williams
2017-04-19 23:13 ` [PATCH v6 07/11] run-command: don't die in child when duping /dev/null Brandon Williams
2017-04-19 23:13 ` [PATCH v6 08/11] run-command: eliminate calls to error handling functions in child Brandon Williams
2017-04-19 23:13 ` [PATCH v6 09/11] run-command: handle dup2 and close errors " Brandon Williams
2017-04-19 23:13 ` [PATCH v6 10/11] run-command: add note about forking and threading Brandon Williams
2017-04-19 23:13 ` [PATCH v6 11/11] run-command: block signals between fork and execve Brandon Williams
2017-04-24 22:37 ` [PATCH v6 00/11] forking and threading Brandon Williams
2017-04-24 23:50 ` [PATCH v6 12/11] run-command: don't try to execute directories Brandon Williams
2017-04-25 0:17 ` Jonathan Nieder
2017-04-25 1:58 ` Junio C Hamano
2017-04-25 2:51 ` Jonathan Nieder
2017-04-25 2:56 ` Jeff King
2017-04-25 1:47 ` Junio C Hamano
2017-04-25 2:57 ` Jonathan Nieder
2017-04-25 17:54 ` [PATCH v7 1/2] exec_cmd: expose is_executable function Brandon Williams
2017-04-25 17:54 ` [PATCH v7 2/2] run-command: don't try to execute directories Brandon Williams
2017-04-25 18:51 ` Jonathan Nieder
2017-04-25 19:32 ` Brandon Williams
2017-04-25 18:04 ` [PATCH v7 1/2] exec_cmd: expose is_executable function Jonathan Nieder
2017-04-25 18:18 ` Johannes Sixt
2017-04-25 18:38 ` Brandon Williams
2017-04-25 23:46 ` [PATCH v8 1/2] run-command: " Brandon Williams
2017-04-25 23:47 ` [PATCH v8 2/2] run-command: restrict PATH search to executable files Brandon Williams
2017-04-25 23:50 ` Jonathan Nieder
2017-04-26 1:44 ` Junio C Hamano [this message]
2017-04-26 17:10 ` [PATCH v9 " Brandon Williams
2017-04-27 0:33 ` Junio C Hamano
2017-04-25 23:48 ` [PATCH v8 1/2] run-command: expose is_executable function Jonathan Nieder
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