From: Al Viro <viro@ZenIV.linux.org.uk>
To: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>,
netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org,
linux-kernel@vger.kernel.org,
Antonio Quartulli <antonio@meshcoding.com>,
"David S. Miller" <davem@davemloft.net>,
Marek Lindner <mareklindner@neomailbox.ch>
Subject: Re: [B.A.T.M.A.N.] [PATCH -next 2/3] batman-adv: Use seq_overflow
Date: Wed, 11 Dec 2013 08:05:04 +0000 [thread overview]
Message-ID: <20131211080504.GT10323@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20131211075526.GR10323@ZenIV.linux.org.uk>
On Wed, Dec 11, 2013 at 07:55:26AM +0000, Al Viro wrote:
> This sucker should return 0. Insufficiently large buffer will be handled
> by caller, TYVM, if you give that caller a chance to do so. Returning 1
> from ->show() is a bug in almost all cases, and definitely so in this one.
>
> Just in case somebody decides that above is worth copying: It Is Not.
> Original code is buggy, plain and simple. This one trades the older
> bug ("fail with -EINVAL whenever the buffer is too small") with just as buggy
> "silently skip an entry entirely whenever the buffer is too small".
>
> Don't Do That.
Pardon - Joe has made seq_overflow return -1 instead of true. Correction
to the above, then - s/This trades.*\./This is just as buggy./
Conclusion is still the same - Don't Do That. Returning -1 on insufficiently
large buffer is a bug, plain and simple.
And this patch series is completely misguided - it doesn't fix any bugs
*and* it provides a misleading example for everyone. See the reaction
right in this thread, proposing to spread the same bug to currently
working iterators.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>,
Marek Lindner <mareklindner@neomailbox.ch>,
Simon Wunderlich <sw@simonwunderlich.de>,
Antonio Quartulli <antonio@meshcoding.com>,
"David S. Miller" <davem@davemloft.net>,
b.a.t.m.a.n@lists.open-mesh.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next 2/3] batman-adv: Use seq_overflow
Date: Wed, 11 Dec 2013 08:05:04 +0000 [thread overview]
Message-ID: <20131211080504.GT10323@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20131211075526.GR10323@ZenIV.linux.org.uk>
On Wed, Dec 11, 2013 at 07:55:26AM +0000, Al Viro wrote:
> This sucker should return 0. Insufficiently large buffer will be handled
> by caller, TYVM, if you give that caller a chance to do so. Returning 1
> from ->show() is a bug in almost all cases, and definitely so in this one.
>
> Just in case somebody decides that above is worth copying: It Is Not.
> Original code is buggy, plain and simple. This one trades the older
> bug ("fail with -EINVAL whenever the buffer is too small") with just as buggy
> "silently skip an entry entirely whenever the buffer is too small".
>
> Don't Do That.
Pardon - Joe has made seq_overflow return -1 instead of true. Correction
to the above, then - s/This trades.*\./This is just as buggy./
Conclusion is still the same - Don't Do That. Returning -1 on insufficiently
large buffer is a bug, plain and simple.
And this patch series is completely misguided - it doesn't fix any bugs
*and* it provides a misleading example for everyone. See the reaction
right in this thread, proposing to spread the same bug to currently
working iterators.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
To: Joe Perches <joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
Cc: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Antonio Quartulli
<antonio-x4xJYDvStAgysxA8WJXlww@public.gmane.org>,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
Marek Lindner
<mareklindner-rVWd3aGhH2z5bpWLKbzFeg@public.gmane.org>
Subject: Re: [PATCH -next 2/3] batman-adv: Use seq_overflow
Date: Wed, 11 Dec 2013 08:05:04 +0000 [thread overview]
Message-ID: <20131211080504.GT10323@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20131211075526.GR10323-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
On Wed, Dec 11, 2013 at 07:55:26AM +0000, Al Viro wrote:
> This sucker should return 0. Insufficiently large buffer will be handled
> by caller, TYVM, if you give that caller a chance to do so. Returning 1
> from ->show() is a bug in almost all cases, and definitely so in this one.
>
> Just in case somebody decides that above is worth copying: It Is Not.
> Original code is buggy, plain and simple. This one trades the older
> bug ("fail with -EINVAL whenever the buffer is too small") with just as buggy
> "silently skip an entry entirely whenever the buffer is too small".
>
> Don't Do That.
Pardon - Joe has made seq_overflow return -1 instead of true. Correction
to the above, then - s/This trades.*\./This is just as buggy./
Conclusion is still the same - Don't Do That. Returning -1 on insufficiently
large buffer is a bug, plain and simple.
And this patch series is completely misguided - it doesn't fix any bugs
*and* it provides a misleading example for everyone. See the reaction
right in this thread, proposing to spread the same bug to currently
working iterators.
next prev parent reply other threads:[~2013-12-11 8:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 5:12 [B.A.T.M.A.N.] [PATCH -next 0/3] seq_printf/puts/putc: Start to convert to return void Joe Perches
2013-12-11 5:12 ` Joe Perches
2013-12-11 5:12 ` [PATCH -next 1/3] seq: Add a seq_overflow test Joe Perches
2013-12-11 23:27 ` Ryan Mallon
2013-12-11 23:31 ` Joe Perches
2013-12-11 5:12 ` [B.A.T.M.A.N.] [PATCH -next 2/3] batman-adv: Use seq_overflow Joe Perches
2013-12-11 5:12 ` Joe Perches
2013-12-11 5:12 ` Joe Perches
2013-12-11 7:26 ` [B.A.T.M.A.N.] " Antonio Quartulli
2013-12-11 7:26 ` Antonio Quartulli
2013-12-11 7:26 ` Antonio Quartulli
2013-12-11 7:31 ` [B.A.T.M.A.N.] " Antonio Quartulli
2013-12-11 7:31 ` Antonio Quartulli
2013-12-11 7:31 ` [B.A.T.M.A.N.] " Antonio Quartulli
2013-12-11 7:58 ` Al Viro
2013-12-11 7:58 ` Al Viro
2013-12-11 7:58 ` [B.A.T.M.A.N.] " Al Viro
2013-12-11 7:55 ` Al Viro
2013-12-11 7:55 ` Al Viro
2013-12-11 7:55 ` Al Viro
2013-12-11 8:05 ` Al Viro [this message]
2013-12-11 8:05 ` Al Viro
2013-12-11 8:05 ` Al Viro
2013-12-11 8:26 ` [B.A.T.M.A.N.] " Joe Perches
2013-12-11 8:26 ` Joe Perches
2013-12-11 8:26 ` Joe Perches
2013-12-11 8:38 ` [B.A.T.M.A.N.] " Al Viro
2013-12-11 8:38 ` Al Viro
2013-12-11 8:38 ` Al Viro
2013-12-11 5:12 ` [PATCH -next 3/3] netfilter: " Joe Perches
2013-12-11 8:17 ` Al Viro
2013-12-11 5:20 ` [B.A.T.M.A.N.] [PATCH -next 0/3] seq_printf/puts/putc: Start to convert to return void David Miller
2013-12-11 5:20 ` David Miller
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