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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id h13-20020aa796cd000000b00540a346477csm133564pfq.76.2022.09.26.17.39.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Sep 2022 17:39:55 -0700 (PDT) From: Kees Cook To: Alexandra Winter Cc: Kees Cook , Wenjia Zhang , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] s390/qeth: Split memcpy() of struct qeth_ipacmd_addr_change flexible array Date: Mon, 26 Sep 2022 17:39:53 -0700 Message-Id: <20220927003953.1942442-1-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1525; h=from:subject; bh=bUXptYsfn3QynH+ULXH8Hc9/lgFc7+jyEV9USOVT9ms=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjMkZYJo3tqJvuRRvDT0Kc6P0APNVENYY0JXVpJPN6 o6X87pSJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYzJGWAAKCRCJcvTf3G3AJoKLD/ 4pR/ZckZK4sdm9vPPPFA6WxL7A7xzH3EEfNBZ9NGAtkbm3elkZ/DRy0ULpzf7cp9z3/+g8ELZZio3Q llnRP2YMWF2GtNjMvhOctWgPQs7E3S80c5K3o5/j8A4PCZYo1RZli9eCra34cEQVrtKBXRRkspKGkv OjOrwLys51OAEu1HlZi3JckcCBQjGMjGQdDY+kk08Gt2XJv7N7iUxvy4kpp4bF6jobSVhmpKkyvDZt Mv4ydOMUF0j03BktcAJ4z/EtNf4JRPYuoVZIm1+JQiG51ewlVlndEhZ6kCiiIQPdq+RkkR/sMMC0s1 tsByRgpVn4jm95vXnuFV6lzdXnFSlsLQnTsjktuThpW+Nl5Cy0BVubYDZlOUlEcwP8u7PFiOkPcoWo 6Alczo9emoomb9jpWVbfd1Y5E2mW+mwukZlPd5z561oY2BDXC5oPLjCf5pDiRrM1pej99tT9ecFlTc ntLfR9LdRzBrQoyya648IpdOWzMgF5/VqJAaijut2pe7EYXILso1I6wKy0pvf1HLwE2DEv5kKUrMkm CfjGvONdqD3v0wbW3/p5bxPOac1ZgjsdxeF5a83y+Yn4MaY1MQRE4oQg/8DptmBvHLCooSHxqfRaG9 R8ITRB0DB14zuluOnP1MMssvrXDnUVNElfF2eAUJLu5LYQ9dEMKNeDvKstJA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org To work around a misbehavior of the compiler's ability to see into composite flexible array structs (as detailed in the coming memcpy() hardening series[1]), split the memcpy() of the header and the payload so no false positive run-time overflow warning will be generated. [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/ Cc: Alexandra Winter Cc: Wenjia Zhang Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: linux-s390@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Alexandra Winter --- drivers/s390/net/qeth_l2_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 2d4436cbcb47..0ce635b7b472 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -1530,8 +1530,8 @@ static void qeth_addr_change_event(struct qeth_card *card, else INIT_DELAYED_WORK(&data->dwork, qeth_l2_dev2br_worker); data->card = card; - memcpy(&data->ac_event, hostevs, - sizeof(struct qeth_ipacmd_addr_change) + extrasize); + data->ac_event = *hostevs; + memcpy(data->ac_event.entry, hostevs->entry, extrasize); queue_delayed_work(card->event_wq, &data->dwork, 0); }