From: Christian Brauner <christian.brauner@ubuntu.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: linux-kernel@vger.kernel.org, Martin Sebor <msebor@gcc.gnu.org>,
Serge Hallyn <serge@hallyn.com>, James Morris <jmorris@namei.org>,
Arnd Bergmann <arnd@arndb.de>,
x86@kernel.org, Ning Sun <ning.sun@intel.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
Kalle Valo <kvalo@codeaurora.org>,
Simon Kelley <simon@thekelleys.org.uk>,
James Smart <james.smart@broadcom.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
Anders Larsen <al@alarsen.net>, Tejun Heo <tj@kernel.org>,
Imre Deak <imre.deak@intel.com>,
linux-arm-kernel@lists.infradead.org,
tboot-devel@lists.sourceforge.net,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
netdev@vger.kernel.org, linux-scsi@vger.kernel.org,
cgroups@vger.kernel.org, linux-security-module@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
Miklos Szeredi <mszeredi@redhat.com>,
Tycho Andersen <tycho@tycho.pizza>
Subject: Re: [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning
Date: Mon, 22 Mar 2021 17:31:31 +0100 [thread overview]
Message-ID: <20210322163131.yaovowes2raydgyg@wittgenstein> (raw)
In-Reply-To: <20210322160253.4032422-4-arnd@kernel.org>
On Mon, Mar 22, 2021 at 05:02:41PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> gcc-11 introdces a harmless warning for cap_inode_getsecurity:
>
> security/commoncap.c: In function ‘cap_inode_getsecurity’:
> security/commoncap.c:440:33: error: ‘memcpy’ reading 16 bytes from a region of size 0 [-Werror=stringop-overread]
> 440 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> The problem here is that tmpbuf is initialized to NULL, so gcc assumes
> it is not accessible unless it gets set by vfs_getxattr_alloc(). This is
> a legitimate warning as far as I can tell, but the code is correct since
> it correctly handles the error when that function fails.
>
> Add a separate NULL check to tell gcc about it as well.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
Seems reasonable,
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
next prev parent reply other threads:[~2021-03-22 16:33 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 16:02 [PATCH 00/11] treewide: address gcc-11 -Wstringop-overread warnings Arnd Bergmann
2021-03-22 16:02 ` [PATCH 01/11] x86: compressed: avoid gcc-11 -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02 ` [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning Arnd Bergmann
2021-03-22 20:29 ` Ingo Molnar
2021-03-22 21:39 ` Arnd Bergmann
2021-03-22 22:07 ` Martin Sebor
2021-03-22 22:49 ` Arnd Bergmann
2021-03-22 23:13 ` Ingo Molnar
2021-03-24 9:11 ` David Laight
2021-03-24 10:39 ` David Laight
2021-03-22 16:02 ` [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:31 ` Christian Brauner [this message]
2021-03-24 20:50 ` James Morris
2021-03-22 16:02 ` [PATCH 04/11] ath11: Wstringop-overread warning Arnd Bergmann
2021-09-28 9:04 ` Kalle Valo
2021-03-22 16:02 ` [PATCH 05/11] qnx: avoid -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02 ` [PATCH 06/11] cgroup: fix -Wzero-length-bounds warnings Arnd Bergmann
2021-03-30 8:41 ` Michal Koutný
2021-03-30 9:00 ` Arnd Bergmann
2021-03-30 14:44 ` Michal Koutný
2021-03-22 16:02 ` [PATCH 07/11] ARM: sharpsl_param: work around -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02 ` [PATCH 08/11] atmel: avoid gcc -Wstringop-overflow warning Arnd Bergmann
2021-03-22 16:02 ` [PATCH 09/11] scsi: lpfc: fix gcc -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02 ` [PATCH 10/11] drm/i915: avoid stringop-overread warning on pri_latency Arnd Bergmann
2021-03-24 15:30 ` Jani Nikula
2021-03-24 17:22 ` Ville Syrjälä
2021-03-22 16:02 ` [PATCH 11/11] [RFC] drm/i915/dp: fix array overflow warning Arnd Bergmann
2021-03-25 8:05 ` Jani Nikula
2021-03-25 9:53 ` Arnd Bergmann
2021-03-25 14:49 ` Martin Sebor
2021-03-30 10:56 ` Hans de Goede
2021-04-06 4:53 ` [PATCH 00/11] treewide: address gcc-11 -Wstringop-overread warnings Martin K. Petersen
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