From: Dan Carpenter <dan.carpenter@oracle.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "'Chen Huang'" <chenhuang5@huawei.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>,
Joseph Qi <joseph.qi@linux.alibaba.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Jens Axboe <axboe@kernel.dk>,
Yang Yingliang <yangyingliang@huawei.com>,
Masahiro Yamada <masahiroy@kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"ocfs2-devel@oss.oracle.com" <ocfs2-devel@oss.oracle.com>
Subject: Re: [PATCH -next 2/3] xen: balloon: Replaced simple_strtoull() with kstrtoull()
Date: Thu, 27 May 2021 17:37:30 +0300 [thread overview]
Message-ID: <20210527143729.GL24442@kadam> (raw)
In-Reply-To: <0f03f9b9ff41460db2935e077f7f80c7@AcuMS.aculab.com>
On Thu, May 27, 2021 at 02:10:21PM +0000, David Laight wrote:
> From: Chen Huang
> > Sent: 26 May 2021 10:20
> >
> > The simple_strtoull() function is deprecated in some situation, since
> > it does not check for the range overflow, use kstrtoull() instead.
> >
> ...
> > - target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
> > + ret = kstrtoull(buf, 0, &target_bytes);
> > + if (ret)
> > + return ret;
> > + target_bytes *= 1024;
>
> I'd have thought it was more important to check *endchar
> than overflow.
That's one of the differences between simple_strtoull() and kstrtoull().
The simple_strtoull() will accept a string like "123ABC", but kstrtoull()
will only accept NUL terminated numbers or a newline followed by a NUL
terminator. Which is fine in this context because users will be doing
"echo 1234 > /sys/foo".
> If you are worried about overflow you need a range check
> before the multiply.
This is probably a case where if the users cause an integer overflow
then they get what they deserve.
regards,
dan carpenter
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Stefano Stabellini <sstabellini@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Yang Yingliang <yangyingliang@huawei.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Nathan Lynch <nathanl@linux.ibm.com>,
Jens Axboe <axboe@kernel.dk>,
Andrew Donnellan <ajd@linux.ibm.com>,
'Chen Huang' <chenhuang5@huawei.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Masahiro Yamada <masahiroy@kernel.org>,
"ocfs2-devel@oss.oracle.com" <ocfs2-devel@oss.oracle.com>
Subject: Re: [Ocfs2-devel] [PATCH -next 2/3] xen: balloon: Replaced simple_strtoull() with kstrtoull()
Date: Thu, 27 May 2021 17:37:30 +0300 [thread overview]
Message-ID: <20210527143729.GL24442@kadam> (raw)
In-Reply-To: <0f03f9b9ff41460db2935e077f7f80c7@AcuMS.aculab.com>
On Thu, May 27, 2021 at 02:10:21PM +0000, David Laight wrote:
> From: Chen Huang
> > Sent: 26 May 2021 10:20
> >
> > The simple_strtoull() function is deprecated in some situation, since
> > it does not check for the range overflow, use kstrtoull() instead.
> >
> ...
> > - target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
> > + ret = kstrtoull(buf, 0, &target_bytes);
> > + if (ret)
> > + return ret;
> > + target_bytes *= 1024;
>
> I'd have thought it was more important to check *endchar
> than overflow.
That's one of the differences between simple_strtoull() and kstrtoull().
The simple_strtoull() will accept a string like "123ABC", but kstrtoull()
will only accept NUL terminated numbers or a newline followed by a NUL
terminator. Which is fine in this context because users will be doing
"echo 1234 > /sys/foo".
> If you are worried about overflow you need a range check
> before the multiply.
This is probably a case where if the users cause an integer overflow
then they get what they deserve.
regards,
dan carpenter
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
Joseph Qi <joseph.qi@linux.alibaba.com>,
Paul Mackerras <paulus@samba.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Stefano Stabellini <sstabellini@kernel.org>,
Mark Fasheh <mark@fasheh.com>,
Yang Yingliang <yangyingliang@huawei.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Nathan Lynch <nathanl@linux.ibm.com>,
Jens Axboe <axboe@kernel.dk>,
Andrew Donnellan <ajd@linux.ibm.com>,
'Chen Huang' <chenhuang5@huawei.com>,
Joel Becker <jlbec@evilplan.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Masahiro Yamada <masahiroy@kernel.org>,
"ocfs2-devel@oss.oracle.com" <ocfs2-devel@oss.oracle.com>
Subject: Re: [PATCH -next 2/3] xen: balloon: Replaced simple_strtoull() with kstrtoull()
Date: Thu, 27 May 2021 17:37:30 +0300 [thread overview]
Message-ID: <20210527143729.GL24442@kadam> (raw)
In-Reply-To: <0f03f9b9ff41460db2935e077f7f80c7@AcuMS.aculab.com>
On Thu, May 27, 2021 at 02:10:21PM +0000, David Laight wrote:
> From: Chen Huang
> > Sent: 26 May 2021 10:20
> >
> > The simple_strtoull() function is deprecated in some situation, since
> > it does not check for the range overflow, use kstrtoull() instead.
> >
> ...
> > - target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
> > + ret = kstrtoull(buf, 0, &target_bytes);
> > + if (ret)
> > + return ret;
> > + target_bytes *= 1024;
>
> I'd have thought it was more important to check *endchar
> than overflow.
That's one of the differences between simple_strtoull() and kstrtoull().
The simple_strtoull() will accept a string like "123ABC", but kstrtoull()
will only accept NUL terminated numbers or a newline followed by a NUL
terminator. Which is fine in this context because users will be doing
"echo 1234 > /sys/foo".
> If you are worried about overflow you need a range check
> before the multiply.
This is probably a case where if the users cause an integer overflow
then they get what they deserve.
regards,
dan carpenter
next prev parent reply other threads:[~2021-05-27 14:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-26 9:20 [PATCH -next 1/3] powerpc/rtas: Replaced simple_strtoull() with kstrtoull() Chen Huang
2021-05-26 9:20 ` Chen Huang
2021-05-26 9:20 ` [Ocfs2-devel] " Chen Huang
2021-05-26 9:20 ` [PATCH -next 2/3] xen: balloon: " Chen Huang
2021-05-26 9:20 ` Chen Huang
2021-05-26 9:20 ` [Ocfs2-devel] " Chen Huang
2021-05-27 14:10 ` David Laight
2021-05-27 14:10 ` David Laight
2021-05-27 14:10 ` [Ocfs2-devel] " David Laight
2021-05-27 14:37 ` Dan Carpenter [this message]
2021-05-27 14:37 ` Dan Carpenter
2021-05-27 14:37 ` [Ocfs2-devel] " Dan Carpenter
2021-05-26 9:20 ` [PATCH -next 3/3] ocfs2: " Chen Huang
2021-05-26 9:20 ` Chen Huang
2021-05-26 9:20 ` [Ocfs2-devel] " Chen Huang
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