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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id y13sm2710073pjr.50.2021.08.17.23.24.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Aug 2021 23:24:12 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Chris Mason , Josef Bacik , David Sterba , linux-btrfs@vger.kernel.org, "Gustavo A. R. Silva" , Greg Kroah-Hartman , Andrew Morton , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, Rasmus Villemoes , linux-hardening@vger.kernel.org Subject: [PATCH v2 49/63] btrfs: Use memset_startat() to clear end of struct Date: Tue, 17 Aug 2021 23:05:19 -0700 Message-Id: <20210818060533.3569517-50-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210818060533.3569517-1-keescook@chromium.org> References: <20210818060533.3569517-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1202; h=from:subject; bh=j07ODF9kjbRRiHohObgJ1N/RHPZCTrQAmspnQvku4YA=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhHKMpNf/1TOA8EHO13yPM2WoVQcddjcJSpXNg/q95 NGD5Kx+JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYRyjKQAKCRCJcvTf3G3AJiFDD/ 43YRq8chsycAfEPzeH3ODP8oX8vzyejO0KZxGwB29jISLONkndclAADo87JB841bplfSqHF4g/N0Yr 9BPUFM/u9aD6MYInBsgRcfvidkMVdvLwJHJroTXouReKf+wENJpCE42XqDFb6/OHW+qszfq48l2ZsZ vlrJcOJH5B/7MGz2vGlPOqarS6QPhKxELyHgWma5US/BF+fmqXoGyLI96PzJHBVwD8Fv1vRW+FZyYX mS0c778XSYdo50TMLiLEeybc58/w6WbytsuOe2gDRaDra0L+tnQU3bUemlEwF/otdXngLgjznL3aHr 03wBbU/uuuYnsF2VxKSH3eTmyOXxM0Fc0gfhMAHlPYOx3FWaj25UujliZBiwYTeajzJsMlNaMxhyYC CNKnLKNfyeqkcnmjrNFG0fLVNoy2o0OR5zMuoedsu9e9ywbM82GfxRkHbOU9ZMZ5GgY2NMQXjzSHXm JS7ECNId/+w48q42Qz1RDDbkk71kX5clz/7ywEULnxcdaVF9VLida+SAjBnEmtDTTT5a3LFsbnweA7 31UgpReo5DWgV9+9dvXi/NGJgP+uufVyB7FGtNrTHKNpqkfmCVfC6YFh7uVwrtuLat1U/8LUy3Rdgf RT0NM3pRRzNQ/fI9ZSg5+8wsIv5qwbvYlgUlhc046qXy22//QbKOPQkqvAQQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Use memset_startat() so memset() doesn't get confused about writing beyond the destination member that is intended to be the starting point of zeroing through the end of the struct. Cc: Chris Mason Cc: Josef Bacik Cc: David Sterba Cc: linux-btrfs@vger.kernel.org Signed-off-by: Kees Cook --- fs/btrfs/root-tree.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c index 702dc5441f03..12ceb14a1141 100644 --- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -39,10 +39,8 @@ static void btrfs_read_root_item(struct extent_buffer *eb, int slot, need_reset = 1; } if (need_reset) { - memset(&item->generation_v2, 0, - sizeof(*item) - offsetof(struct btrfs_root_item, - generation_v2)); - + /* Clear all members from generation_v2 onwards. */ + memset_startat(item, 0, generation_v2); generate_random_guid(item->uuid); } } -- 2.30.2