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dm integrity: use crypto_shash_digest() in sb_mac()

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Simplify sb_mac() by using crypto_shash_digest() instead of an
init+update+final sequence.  This should also improve performance.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Eric Biggers 2023-10-28 21:59:44 -07:00 committed by Mike Snitzer
parent 6d0ee3b680
commit 070bb43ab0
1 changed files with 10 additions and 20 deletions
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30
drivers/md/dm-integrity.c
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@ -493,42 +493,32 @@ static int sb_mac(struct dm_integrity_c *ic, bool wr)
{
SHASH_DESC_ON_STACK(desc, ic->journal_mac);
int r;
unsigned int size = crypto_shash_digestsize(ic->journal_mac);
unsigned int mac_size = crypto_shash_digestsize(ic->journal_mac);
__u8 *sb = (__u8 *)ic->sb;
__u8 *mac = sb + (1 << SECTOR_SHIFT) - mac_size;
if (sizeof(struct superblock) + size > 1 << SECTOR_SHIFT) {
if (sizeof(struct superblock) + mac_size > 1 << SECTOR_SHIFT) {
dm_integrity_io_error(ic, "digest is too long", -EINVAL);
return -EINVAL;
}
desc->tfm = ic->journal_mac;
r = crypto_shash_init(desc);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_init", r);
return r;
}
r = crypto_shash_update(desc, (__u8 *)ic->sb, (1 << SECTOR_SHIFT) - size);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_update", r);
return r;
}
if (likely(wr)) {
r = crypto_shash_final(desc, (__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size);
r = crypto_shash_digest(desc, sb, mac - sb, mac);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_final", r);
dm_integrity_io_error(ic, "crypto_shash_digest", r);
return r;
}
} else {
__u8 result[HASH_MAX_DIGESTSIZE];
__u8 actual_mac[HASH_MAX_DIGESTSIZE];
r = crypto_shash_final(desc, result);
r = crypto_shash_digest(desc, sb, mac - sb, actual_mac);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_final", r);
dm_integrity_io_error(ic, "crypto_shash_digest", r);
return r;
}
if (memcmp((__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size, result, size)) {
if (memcmp(mac, actual_mac, mac_size)) {
dm_integrity_io_error(ic, "superblock mac", -EILSEQ);
dm_audit_log_target(DM_MSG_PREFIX, "mac-superblock", ic->ti, 0);
return -EILSEQ;