Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH v2 49/63] btrfs: Use memset_startat() to clear end of struct | Date | Tue, 17 Aug 2021 23:05:19 -0700 |
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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 <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: David Sterba <dsterba@suse.com> Cc: linux-btrfs@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- 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
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