In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Add struct_group() to mark region of struct journal_sector that should be initialized to zero.
Cc: Alasdair Kergon agk@redhat.com Cc: Mike Snitzer snitzer@redhat.com Cc: dm-devel@redhat.com Signed-off-by: Kees Cook keescook@chromium.org --- drivers/md/dm-integrity.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 40f8116c8e44..59deea0dd305 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -119,8 +119,10 @@ struct journal_entry { #define JOURNAL_MAC_SIZE (JOURNAL_MAC_PER_SECTOR * JOURNAL_BLOCK_SECTORS)
struct journal_sector { - __u8 entries[JOURNAL_SECTOR_DATA - JOURNAL_MAC_PER_SECTOR]; - __u8 mac[JOURNAL_MAC_PER_SECTOR]; + struct_group(sectors, + __u8 entries[JOURNAL_SECTOR_DATA - JOURNAL_MAC_PER_SECTOR]; + __u8 mac[JOURNAL_MAC_PER_SECTOR]; + ); commit_id_t commit_id; };
@@ -2856,7 +2858,8 @@ static void init_journal(struct dm_integrity_c *ic, unsigned start_section, wraparound_section(ic, &i); for (j = 0; j < ic->journal_section_sectors; j++) { struct journal_sector *js = access_journal(ic, i, j); - memset(&js->entries, 0, JOURNAL_SECTOR_DATA); + BUILD_BUG_ON(sizeof(js->sectors) != JOURNAL_SECTOR_DATA); + memset(&js->sectors, 0, sizeof(js->sectors)); js->commit_id = dm_integrity_commit_id(ic, i, j, commit_seq); } for (j = 0; j < ic->journal_section_entries; j++) {