[PATCH v3 2/3] dm integrity: log audit events for dm-integrity target
dm-integrity signals integrity violations by returning I/O errors
to user space. To identify integrity violations by a controlling
instance, the kernel audit subsystem can be used to emit audit
events to user space. We use the new dm-audit submodule allowing
to emit audit events on relevant I/O errors.
The construction and destruction of integrity device mappings are
also relevant for auditing a system. Thus, those events are also
logged as audit events.
Signed-off-by: Michael Weiß <michael.weiss(a)aisec.fraunhofer.de>
---
drivers/md/dm-integrity.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 20f2510db1f6..a881ead4b506 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -23,6 +23,8 @@
#include <linux/async_tx.h>
#include <linux/dm-bufio.h>
+#include "dm-audit.h"
+
#define DM_MSG_PREFIX "integrity"
#define DEFAULT_INTERLEAVE_SECTORS 32768
@@ -539,6 +541,7 @@ static int sb_mac(struct dm_integrity_c *ic, bool wr)
}
if (memcmp((__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size, result, size)) {
dm_integrity_io_error(ic, "superblock mac", -EILSEQ);
+ dm_audit_log_target(DM_MSG_PREFIX, "mac-superblock", ic->ti, 0);
return -EILSEQ;
}
}
@@ -876,8 +879,10 @@ static void rw_section_mac(struct dm_integrity_c *ic, unsigned
section, bool wr)
if (likely(wr))
memcpy(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR),
JOURNAL_MAC_PER_SECTOR);
else {
- if (memcmp(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR),
JOURNAL_MAC_PER_SECTOR))
+ if (memcmp(&js->mac, result + (j * JOURNAL_MAC_PER_SECTOR),
JOURNAL_MAC_PER_SECTOR)) {
dm_integrity_io_error(ic, "journal mac", -EILSEQ);
+ dm_audit_log_target(DM_MSG_PREFIX, "mac-journal", ic->ti, 0);
+ }
}
}
}
@@ -1782,10 +1787,15 @@ static void integrity_metadata(struct work_struct *w)
if (unlikely(r)) {
if (r > 0) {
char b[BDEVNAME_SIZE];
- DMERR_LIMIT("%s: Checksum failed at sector 0x%llx", bio_devname(bio, b),
- (sector - ((r + ic->tag_size - 1) / ic->tag_size)));
+ sector_t s;
+
+ s = sector - ((r + ic->tag_size - 1) / ic->tag_size);
+ DMERR_LIMIT("%s: Checksum failed at sector 0x%llx",
+ bio_devname(bio, b), s);
r = -EILSEQ;
atomic64_inc(&ic->number_of_mismatches);
+ dm_audit_log_bio(DM_MSG_PREFIX, "integrity-checksum",
+ bio, s, 0);
}
if (likely(checksums != checksums_onstack))
kfree(checksums);
@@ -1991,6 +2001,8 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct
bio *bio,
if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size)))
{
DMERR_LIMIT("Checksum failed when reading from journal, at sector
0x%llx",
logical_sector);
+ dm_audit_log_bio(DM_MSG_PREFIX, "journal-checksum",
+ bio, logical_sector, 0);
}
}
#endif
@@ -2534,8 +2546,10 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned
write_start,
integrity_sector_checksum(ic, sec + ((l - j) <<
ic->sb->log2_sectors_per_block),
(char *)access_journal_data(ic, i, l), test_tag);
- if (unlikely(memcmp(test_tag, journal_entry_tag(ic, je2), ic->tag_size)))
+ if (unlikely(memcmp(test_tag, journal_entry_tag(ic, je2), ic->tag_size))) {
dm_integrity_io_error(ic, "tag mismatch when replaying journal",
-EILSEQ);
+ dm_audit_log_target(DM_MSG_PREFIX, "integrity-replay-journal", ic->ti,
0);
+ }
}
journal_entry_set_unused(je2);
@@ -4490,9 +4504,11 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc,
char **argv)
if (ic->discard)
ti->num_discard_bios = 1;
+ dm_audit_log_ctr(DM_MSG_PREFIX, ti, 1);
return 0;
bad:
+ dm_audit_log_ctr(DM_MSG_PREFIX, ti, 0);
dm_integrity_dtr(ti);
return r;
}
@@ -4566,6 +4582,7 @@ static void dm_integrity_dtr(struct dm_target *ti)
free_alg(&ic->journal_mac_alg);
kfree(ic);
+ dm_audit_log_dtr(DM_MSG_PREFIX, ti, 1);
}
static struct target_type integrity_target = {
--
2.20.1