From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: [PATCH 05/11] qnx: avoid -Wstringop-overread warning Date: Mon, 22 Mar 2021 17:02:43 +0100 Message-ID: <20210322160253.4032422-6-arnd@kernel.org> References: <20210322160253.4032422-1-arnd@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616429066; bh=nkpO3F9iV2LP9C5b1X1yN1ZVysmYmotRTLuBUWIaptM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MU4IL9JNNK+J8U+vvpLpwovR+/suU+W9R4RhhhMaub4p/qt1HSm7/5H/LxJjfRA1v f+dccndcC0t+6DndIOBCJbVJvgtAFbUO/Xj+Ad4PAK3HRVGVN0VmdJVzwNG2nWP60W yoMi7GzhcMMul2Me0RQEOrAkh9+ikItIp0T7LrmMn4UxhxHfYhCqAAaad++VD478Ly WRurbxWp7EoqaQbB5aDSFB4iZyCpOkFivtOdus8BKdINgwMELaIsTcoM1dTXGsBCvO NUlZI47cRIaTlBnQpp36y5LIoHJRasVTH3KqfKgtuhF/A3Vph299qnut15q3EDnfE2 ATElHLu2Uchbw== In-Reply-To: <20210322160253.4032422-1-arnd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-ID: Content-Type: text/plain; charset="utf-8" To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Martin Sebor , Anders Larsen Cc: Arnd Bergmann , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Ning Sun , Jani Nikula , Kalle Valo , Simon Kelley , James Smart , "James E.J. Bottomley" , Tejun Heo , Serge Hallyn , Imre Deak , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, tboot-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, ath11k-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org From: Arnd Bergmann gcc-11 warns that the size of the link name is longer than the di_fname field: fs/qnx4/dir.c: In function ‘qnx4_readdir’: fs/qnx4/dir.c:51:32: error: ‘strnlen’ specified bound 48 exceeds source size 16 [-Werror=stringop-overread] 51 | size = strnlen(de->di_fname, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from fs/qnx4/qnx4.h:3, from fs/qnx4/dir.c:16: include/uapi/linux/qnx4_fs.h:45:25: note: source object declared here 45 | char di_fname[QNX4_SHORT_NAME_MAX]; The problem here is that we access the same pointer using two different structure layouts, but gcc determines the object size based on whatever it encounters first. Change the strnlen to use the correct field size in each case, and change the first access to be on the longer field. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578 Signed-off-by: Arnd Bergmann --- fs/qnx4/dir.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c index a6ee23aadd28..68046450e543 100644 --- a/fs/qnx4/dir.c +++ b/fs/qnx4/dir.c @@ -39,21 +39,20 @@ static int qnx4_readdir(struct file *file, struct dir_context *ctx) ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK; for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) { offset = ix * QNX4_DIR_ENTRY_SIZE; - de = (struct qnx4_inode_entry *) (bh->b_data + offset); - if (!de->di_fname[0]) + le = (struct qnx4_link_info *)(bh->b_data + offset); + de = (struct qnx4_inode_entry *)(bh->b_data + offset); + if (!le->dl_fname[0]) continue; if (!(de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK))) continue; if (!(de->di_status & QNX4_FILE_LINK)) - size = QNX4_SHORT_NAME_MAX; + size = strnlen(de->di_fname, sizeof(de->di_fname)); else - size = QNX4_NAME_MAX; - size = strnlen(de->di_fname, size); + size = strnlen(le->dl_fname, sizeof(le->dl_fname)); QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, de->di_fname)); if (!(de->di_status & QNX4_FILE_LINK)) ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1; else { - le = (struct qnx4_link_info*)de; ino = ( le32_to_cpu(le->dl_inode_blk) - 1 ) * QNX4_INODES_PER_BLOCK + le->dl_inode_ndx; -- 2.29.2