From patchwork Mon Apr 7 19:36:26 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. 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R. Silva" To: Krzysztof Kozlowski Cc: linux-kernel@vger.kernel.org, Kees Cook , "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH v2][next] w1: Avoid -Wflex-array-member-not-at-end warnings Message-ID: Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline -Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the `DEFINE_RAW_FLEX()` helper for on-stack definitions of a flexible structure where the size of the flexible-array member is known at compile-time, and refactor the rest of the code, accordingly. So, with these changes, fix the following warnings: drivers/w1/w1_netlink.c:198:31: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] drivers/w1/w1_netlink.c:219:31: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook --- Changes in v2: - Fix memcpy() instance - use new pointer `pkg_msg`, instead of `packet`. (Kees) v1: - Link: https://lore.kernel.org/linux-hardening/Z-WD2NP_1A0ratnI@kspp/ drivers/w1/w1_netlink.c | 42 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 22 deletions(-) diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c index 691978cddab7..724a008cf342 100644 --- a/drivers/w1/w1_netlink.c +++ b/drivers/w1/w1_netlink.c @@ -194,16 +194,16 @@ static void w1_netlink_queue_status(struct w1_cb_block *block, static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg, int portid, int error) { - struct { - struct cn_msg cn; - struct w1_netlink_msg msg; - } packet; - memcpy(&packet.cn, cn, sizeof(packet.cn)); - memcpy(&packet.msg, msg, sizeof(packet.msg)); - packet.cn.len = sizeof(packet.msg); - packet.msg.len = 0; - packet.msg.status = (u8)-error; - cn_netlink_send(&packet.cn, portid, 0, GFP_KERNEL); + DEFINE_RAW_FLEX(struct cn_msg, packet, data, + sizeof(struct w1_netlink_msg)); + struct w1_netlink_msg *pkt_msg = (struct w1_netlink_msg *)packet->data; + + memcpy(packet, cn, sizeof(*packet)); + memcpy(pkt_msg, msg, sizeof(*pkt_msg)); + packet->len = sizeof(*pkt_msg); + pkt_msg->len = 0; + pkt_msg->status = (u8)-error; + cn_netlink_send(packet, portid, 0, GFP_KERNEL); } /** @@ -215,22 +215,20 @@ static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg, */ void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg) { - struct { - struct cn_msg cn; - struct w1_netlink_msg msg; - } packet; - memset(&packet, 0, sizeof(packet)); + DEFINE_RAW_FLEX(struct cn_msg, packet, data, + sizeof(struct w1_netlink_msg)); + struct w1_netlink_msg *pkg_msg = (struct w1_netlink_msg *)packet->data; - packet.cn.id.idx = CN_W1_IDX; - packet.cn.id.val = CN_W1_VAL; + packet->id.idx = CN_W1_IDX; + packet->id.val = CN_W1_VAL; - packet.cn.seq = dev->seq++; - packet.cn.len = sizeof(*msg); + packet->seq = dev->seq++; + packet->len = sizeof(*msg); - memcpy(&packet.msg, msg, sizeof(*msg)); - packet.msg.len = 0; + memcpy(pkg_msg, msg, sizeof(*msg)); + pkg_msg->len = 0; - cn_netlink_send(&packet.cn, 0, 0, GFP_KERNEL); + cn_netlink_send(packet, 0, 0, GFP_KERNEL); } static void w1_send_slave(struct w1_master *dev, u64 rn)