From: Kees Cook <keescook@chromium.org>
To: Alasdair Kergon <agk@redhat.com>
Cc: Kees Cook <keescook@chromium.org>,
Mike Snitzer <snitzer@redhat.com>,
linux-kernel@vger.kernel.org, dm-devel@redhat.com,
linux-hardening@vger.kernel.org
Subject: [PATCH] dm integrity: Use struct_group() to zero struct journal_sector
Date: Thu, 18 Nov 2021 12:36:40 -0800 [thread overview]
Message-ID: <20211118203640.1288585-1-keescook@chromium.org> (raw)
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.
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 6319deccbe09..163c94ca4e5c 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -121,8 +121,10 @@ 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;
};
@@ -2870,7 +2872,8 @@ 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++) {
--
2.30.2
next reply other threads:[~2021-11-18 20:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 20:36 Kees Cook [this message]
2021-12-13 23:25 ` [dm-devel] [PATCH] dm integrity: Use struct_group() to zero struct journal_sector Gustavo A. R. Silva
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