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From: Arnd Bergmann <arnd@kernel.org>
To: linux-kernel@vger.kernel.org, Martin Sebor <msebor@gcc.gnu.org>,
	Simon Kelley <simon@thekelleys.org.uk>,
	Kalle Valo <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
	x86@kernel.org, Ning Sun <ning.sun@intel.com>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	James Smart <james.smart@broadcom.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Anders Larsen <al@alarsen.net>, Tejun Heo <tj@kernel.org>,
	Serge Hallyn <serge@hallyn.com>, 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,
	Lee Jones <lee.jones@linaro.org>,
	Pascal Terjan <pterjan@google.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>
Subject: [PATCH 08/11] atmel: avoid gcc -Wstringop-overflow warning
Date: Mon, 22 Mar 2021 17:02:46 +0100
Message-ID: <20210322160253.4032422-9-arnd@kernel.org> (raw)
In-Reply-To: <20210322160253.4032422-1-arnd@kernel.org>

From: Arnd Bergmann <arnd@arndb.de>

gcc-11 notices that the fields as defined in the ass_req_format
structure do not match the actual use of that structure:

cc1: error: writing 4 bytes into a region of size between 18446744073709551613 and 2 [-Werror=stringop-overflow=]
drivers/net/wireless/atmel/atmel.c:2884:20: note: at offset [4, 6] into destination object ‘ap’ of size 6
 2884 |                 u8 ap[ETH_ALEN]; /* nothing after here directly accessible */
      |                    ^~
drivers/net/wireless/atmel/atmel.c:2885:20: note: at offset [4, 6] into destination object ‘ssid_el_id’ of size 1
 2885 |                 u8 ssid_el_id;
      |                    ^~~~~~~~~~

This is expected here because the actual structure layout is variable.
As the code does not actually access the individual fields, replace
them with a comment and fixed-length array so prevent gcc from
complaining about it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/atmel/atmel.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/atmel/atmel.c b/drivers/net/wireless/atmel/atmel.c
index 707fe66727f8..ff9152d600e1 100644
--- a/drivers/net/wireless/atmel/atmel.c
+++ b/drivers/net/wireless/atmel/atmel.c
@@ -2881,13 +2881,18 @@ static void send_association_request(struct atmel_private *priv, int is_reassoc)
 	struct ass_req_format {
 		__le16 capability;
 		__le16 listen_interval;
-		u8 ap[ETH_ALEN]; /* nothing after here directly accessible */
-		u8 ssid_el_id;
-		u8 ssid_len;
-		u8 ssid[MAX_SSID_LENGTH];
-		u8 sup_rates_el_id;
-		u8 sup_rates_len;
-		u8 rates[4];
+		u8 ssid_el[ETH_ALEN + 2 + MAX_SSID_LENGTH + 2 + 4];
+		/*
+		 * nothing after here directly accessible:
+		 *
+		 * u8 ap[ETH_ALEN];
+		 * u8 ssid_el_id;
+		 * u8 ssid_len;
+		 * u8 ssid[MAX_SSID_LENGTH];
+		 * u8 sup_rates_el_id;
+		 * u8 sup_rates_len;
+		 * u8 rates[4];
+		 */
 	} body;
 
 	header.frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
@@ -2907,13 +2912,13 @@ static void send_association_request(struct atmel_private *priv, int is_reassoc)
 
 	body.listen_interval = cpu_to_le16(priv->listen_interval * priv->beacon_period);
 
+	ssid_el_p = body.ssid_el;
 	/* current AP address - only in reassoc frame */
 	if (is_reassoc) {
-		memcpy(body.ap, priv->CurrentBSSID, ETH_ALEN);
-		ssid_el_p = &body.ssid_el_id;
+		memcpy(ssid_el_p, priv->CurrentBSSID, ETH_ALEN);
+		ssid_el_p += ETH_ALEN;
 		bodysize = 18 + priv->SSID_size;
 	} else {
-		ssid_el_p = &body.ap[0];
 		bodysize = 12 + priv->SSID_size;
 	}
 
-- 
2.29.2


  parent reply index

Thread overview: 31+ 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
2021-03-24 20:50   ` James Morris
2021-03-22 16:02 ` [PATCH 04/11] ath11: Wstringop-overread warning Arnd Bergmann
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 ` Arnd Bergmann [this message]
2021-03-22 16:02 ` [PATCH 09/11] scsi: lpfc: fix gcc " 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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