iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

btrfs: Use memset_startat() to clear end of struct

Browse Source 
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
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2021-05-20 15:30:56 -07:00
parent 6dbefad408
commit a2c5062f39
1 changed files with 2 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/btrfs/root-tree.c
View File

@ -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);
}
}