| Message ID | 20231011101134.709b8089@imladris.surriel.com |
|---|---|
| State | New |
| Headers |
Return-Path: <linux-kernel-owner@vger.kernel.org>
Delivered-To: ouuuleilei@gmail.com
Received: by 2002:a05:612c:2908:b0:403:3b70:6f57 with SMTP id ib8csp569290vqb;
Wed, 11 Oct 2023 07:12:15 -0700 (PDT)
X-Google-Smtp-Source:
AGHT+IHuxw7iNvYFc3i1cCt9o1JHmZMRMLeTn8nn/1jGYzoBkLs/v0ZZN4Bh9YfrsC3Pfje3aXyy
X-Received: by 2002:a05:6e02:5ce:b0:34f:a4f0:4fc4 with SMTP id
l14-20020a056e0205ce00b0034fa4f04fc4mr20881684ils.2.1697033535216;
Wed, 11 Oct 2023 07:12:15 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; t=1697033535; cv=none;
d=google.com; s=arc-20160816;
b=hjoNGdzLi3UGUqwJ3bBtQ6flDFw5OUpoLIJShQsUd4/TKLRQSbvyKqHwUhuX+DLXSI
KM5x9qhGxSqrIxHq943vhXAjSK9SNRDwTb3BBkko1JcFi6egRbOIWotipZenFfXUCDa1
HenbVnktYp3regHSfGBlRwKXeYXcawIMzBc8Nx8kMYaTCaY87WtaEDo3w6Tf66EweKQU
ApeUcKce03J3vaSttO2B7BVkTHZ5GtT0X4DvhbRXiWRn2TPThZqXjminEzBo3VFFDKzy
GfT1KFwIxIEO1BsoEFuW+24cDUZn8wad84+RoAAMQMQReP5gpPaH/ewYpao88A4Yr42t
4+Og==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com;
s=arc-20160816;
h=list-id:precedence:sender:content-transfer-encoding:mime-version
:message-id:subject:cc:to:from:date;
bh=EEXYnPhszhtrxRcAa0qWRiMZeIJE5Y+LsmZGqghFh6g=;
fh=Uxb8CmDRNETOOABXu/reqwMbtOmB6epPbc1mQgATnvM=;
b=I2JOmmxXIcKNS1FgQa/ve7dVElg8TwwwkCmVz8AmAXKhYH/7SnJlLlN6EoaYPoUOYJ
P26uC/oHtjbMsiLm/FvNpXBkgWsbXckm+wDVf48lPpM6uFdxDWlZYrOqrDkb3RR8h7UQ
z7+P7Ou5xH+woYHli9KvnxOcRhsSGcvIB5sCl8ZiacjxcWkvROCjWQGiDQsyTn3WpfKs
jLCAkNtdFCYyB6vVi04KTw1t4uarc8zI+MhY44S2pFfk8j7qF9Z3fHYTuf09ZPoGtINr
4XWmLsgp0SGxUmE3Ndn4PVfdyZJQBFRpkpV13kx+OX5U5cJC1wucUyw47iGwseaWVF30
Fl2Q==
ARC-Authentication-Results: i=1; mx.google.com;
spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org
designates 23.128.96.35 as permitted sender)
smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: from groat.vger.email (groat.vger.email. [23.128.96.35])
by mx.google.com with ESMTPS id
k67-20020a633d46000000b005a1d8815fefsi290058pga.187.2023.10.11.07.12.14
(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
Wed, 11 Oct 2023 07:12:15 -0700 (PDT)
Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org
designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35;
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org
designates 23.128.96.35 as permitted sender)
smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0])
by groat.vger.email (Postfix) with ESMTP id 130E080725E1;
Wed, 11 Oct 2023 07:12:13 -0700 (PDT)
X-Virus-Status: Clean
X-Virus-Scanned: clamav-milter 0.103.10 at groat.vger.email
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
id S232504AbjJKOL6 (ORCPT <rfc822;kartikey406@gmail.com>
+ 18 others); Wed, 11 Oct 2023 10:11:58 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53034 "EHLO
lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
with ESMTP id S232125AbjJKOL5 (ORCPT
<rfc822;linux-kernel@vger.kernel.org>);
Wed, 11 Oct 2023 10:11:57 -0400
Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147])
by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F2F294;
Wed, 11 Oct 2023 07:11:55 -0700 (PDT)
Received: from [2601:18c:9101:a8b6:6e0b:84ff:fee2:98bb]
(helo=imladris.surriel.com)
by shelob.surriel.com with esmtpsa (TLS1.2) tls
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
(Exim 4.96.1)
(envelope-from <riel@shelob.surriel.com>)
id 1qqZw2-0003Dg-2T;
Wed, 11 Oct 2023 10:11:38 -0400
Date: Wed, 11 Oct 2023 10:11:34 -0400
From: Rik van Riel <riel@surriel.com>
To: Alejandro Colomar <alx@kernel.org>
Cc: linux-man@vger.kernel.org, kernel-team@meta.com,
LKML <linux-kernel@vger.kernel.org>,
Eric Biederman <ebiederm@xmission.com>,
Matthew House <mattlloydhouse@gmail.com>
Subject: [PATCH v2] execve.2: execve also returns E2BIG if a string is too
long
Message-ID: <20231011101134.709b8089@imladris.surriel.com>
X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: riel@surriel.com
X-Spam-Status: No, score=2.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
MAILING_LIST_MULTI,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS autolearn=no
autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.vger.email
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test,
not delayed by milter-greylist-4.6.4 (groat.vger.email [0.0.0.0]);
Wed, 11 Oct 2023 07:12:13 -0700 (PDT)
X-Spam-Level: **
X-getmail-retrieved-from-mailbox: INBOX
X-GMAIL-THRID: 1779468636374485856
X-GMAIL-MSGID: 1779468636374485856
|
| Series |
[v2] execve.2: execve also returns E2BIG if a string is too long
|
|
Commit Message
Rik van Riel
Oct. 11, 2023, 2:11 p.m. UTC
The execve syscall returns -E2BIG in 3 cases:
- The total length of the command line arguments and environment is too large.
- An argument or environment string is longer than MAX_ARG_STRLEN.
- The full path to the executable exceeds MAX_ARG_STRLEN.
Spell out all 3 cases in the -E2BIG section.
Discovered by moving a too large commandline parameter to an environment
variable, and finding that things still did not work. Examined the code
in fs/exec.c to get the details.
Signed-off-by: Rik van Riel <riel@surriel.com>
Suggested-by: Matthew House <mattlloydhouse@gmail.com>
---
man2/execve.2 | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Comments
On Wed, Oct 11, 2023 at 10:11:34AM -0400, Rik van Riel wrote: > The execve syscall returns -E2BIG in 3 cases: > - The total length of the command line arguments and environment is too large. > - An argument or environment string is longer than MAX_ARG_STRLEN. > - The full path to the executable exceeds MAX_ARG_STRLEN. > > Spell out all 3 cases in the -E2BIG section. > > Discovered by moving a too large commandline parameter to an environment > variable, and finding that things still did not work. Examined the code > in fs/exec.c to get the details. > > Signed-off-by: Rik van Riel <riel@surriel.com> > Suggested-by: Matthew House <mattlloydhouse@gmail.com> > --- > man2/execve.2 | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/man2/execve.2 b/man2/execve.2 > index 0d9582492ad1..85c6ec15df3c 100644 > --- a/man2/execve.2 > +++ b/man2/execve.2 > @@ -449,7 +449,8 @@ The total number of bytes in the environment > .RI ( envp ) > and argument list > .RI ( argv ) > -is too large. > +is too large, an argument or environment string is too long, or Please break lines after commas. > +the full path name to the executable is too long. > .TP > .B EACCES > Search permission is denied on a component of the path prefix of > -- > 2.41.0 > >
Hi Rik, On Wed, Oct 11, 2023 at 10:11:34AM -0400, Rik van Riel wrote: > The execve syscall returns -E2BIG in 3 cases: > - The total length of the command line arguments and environment is too large. > - An argument or environment string is longer than MAX_ARG_STRLEN. Please mention that this includes the terminating NUL, as Matthew confirmed. Otherwise, to user-space programmers, this would usually be interpreted as `strlen(p) > MAX_ARG_STRLEN`. An example program that demonstrates the limit would be very interesting here. Thanks, Alex > - The full path to the executable exceeds MAX_ARG_STRLEN. > > Spell out all 3 cases in the -E2BIG section. > > Discovered by moving a too large commandline parameter to an environment > variable, and finding that things still did not work. Examined the code > in fs/exec.c to get the details. > > Signed-off-by: Rik van Riel <riel@surriel.com> > Suggested-by: Matthew House <mattlloydhouse@gmail.com> > --- > man2/execve.2 | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/man2/execve.2 b/man2/execve.2 > index 0d9582492ad1..85c6ec15df3c 100644 > --- a/man2/execve.2 > +++ b/man2/execve.2 > @@ -449,7 +449,8 @@ The total number of bytes in the environment > .RI ( envp ) > and argument list > .RI ( argv ) > -is too large. > +is too large, an argument or environment string is too long, or > +the full path name to the executable is too long. > .TP > .B EACCES > Search permission is denied on a component of the path prefix of > -- > 2.41.0 > >
On Wed, 2023-10-11 at 17:48 +0200, Alejandro Colomar wrote: > Hi Rik, > > On Wed, Oct 11, 2023 at 10:11:34AM -0400, Rik van Riel wrote: > > The execve syscall returns -E2BIG in 3 cases: > > - The total length of the command line arguments and environment is > > too large. > > - An argument or environment string is longer than MAX_ARG_STRLEN. > > Please mention that this includes the terminating NUL, as Matthew > confirmed. Otherwise, to user-space programmers, this would usually > be > interpreted as `strlen(p) > MAX_ARG_STRLEN`. > > An example program that demonstrates the limit would be very > interesting > here. Thank you for the detailed review. I think all the comments are addressed in version 3.
diff --git a/man2/execve.2 b/man2/execve.2 index 0d9582492ad1..85c6ec15df3c 100644 --- a/man2/execve.2 +++ b/man2/execve.2 @@ -449,7 +449,8 @@ The total number of bytes in the environment .RI ( envp ) and argument list .RI ( argv ) -is too large. +is too large, an argument or environment string is too long, or +the full path name to the executable is too long. .TP .B EACCES Search permission is denied on a component of the path prefix of