Disable recalculating if we don't have fix_hmac, the journal hash algorithm is using a kay and we don't have the "legacy_recalculate" flag.
Signed-off-by: Mikulas Patocka <[email protected]> Index: linux-2.6/drivers/md/dm-integrity.c =================================================================== --- linux-2.6.orig/drivers/md/dm-integrity.c +++ linux-2.6/drivers/md/dm-integrity.c @@ -262,6 +262,7 @@ struct dm_integrity_c { bool discard; bool fix_padding; bool fix_hmac; + bool legacy_recalculate; struct alg_spec internal_hash_alg; struct alg_spec journal_crypt_alg; @@ -389,6 +390,15 @@ static int dm_integrity_failed(struct dm return READ_ONCE(ic->failed); } +static bool dm_integrity_disable_recalculate(struct dm_integrity_c *ic) +{ + if (!ic->fix_hmac && + ic->journal_mac_alg.key && + !ic->legacy_recalculate) + return true; + return false; +} + static commit_id_t dm_integrity_commit_id(struct dm_integrity_c *ic, unsigned i, unsigned j, unsigned char seq) { @@ -3221,6 +3231,7 @@ static void dm_integrity_status(struct d arg_count += !!ic->journal_mac_alg.alg_string; arg_count += (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_PADDING)) != 0; arg_count += (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) != 0; + arg_count += ic->legacy_recalculate; DMEMIT("%s %llu %u %c %u", ic->dev->name, ic->start, ic->tag_size, ic->mode, arg_count); if (ic->meta_dev) @@ -3246,6 +3257,8 @@ static void dm_integrity_status(struct d DMEMIT(" fix_padding"); if ((ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) != 0) DMEMIT(" fix_hmac"); + if (ic->legacy_recalculate) + DMEMIT(" legacy_recalculate"); #define EMIT_ALG(a, n) \ do { \ @@ -3878,7 +3891,7 @@ static int dm_integrity_ctr(struct dm_ta unsigned extra_args; struct dm_arg_set as; static const struct dm_arg _args[] = { - {0, 16, "Invalid number of feature args"}, + {0, 17, "Invalid number of feature args"}, }; unsigned journal_sectors, interleave_sectors, buffer_sectors, journal_watermark, sync_msec; bool should_write_sb; @@ -4028,6 +4041,8 @@ static int dm_integrity_ctr(struct dm_ta ic->fix_padding = true; } else if (!strcmp(opt_string, "fix_hmac")) { ic->fix_hmac = true; + } else if (!strcmp(opt_string, "legacy_recalculate")) { + ic->legacy_recalculate = true; } else { r = -EINVAL; ti->error = "Invalid argument"; @@ -4331,6 +4346,14 @@ try_smaller_buffer: } } + if (ic->sb->flags & cpu_to_le32(SB_FLAG_RECALCULATING) && + le64_to_cpu(ic->sb->recalc_sector) < ic->provided_data_sectors && + dm_integrity_disable_recalculate(ic)) { + ti->error = "Recalculating with \"fix_hmac\" is disable for security reasons - if you really need it, use the argument \"legacy_recalculate\""; + r = -EOPNOTSUPP; + goto bad; + } + ic->bufio = dm_bufio_client_create(ic->meta_dev ? ic->meta_dev->bdev : ic->dev->bdev, 1U << (SECTOR_SHIFT + ic->log2_buffer_sectors), 1, 0, NULL, NULL); if (IS_ERR(ic->bufio)) { Index: linux-2.6/Documentation/admin-guide/device-mapper/dm-integrity.rst =================================================================== --- linux-2.6.orig/Documentation/admin-guide/device-mapper/dm-integrity.rst +++ linux-2.6/Documentation/admin-guide/device-mapper/dm-integrity.rst @@ -128,9 +128,15 @@ internal_hash:algorithm(:key) (the key i You can use a crc algorithm (such as crc32), then integrity target will protect the data against accidental corruption. - You can also use a hmac algorithm (for example - "hmac(sha256):0123456789abcdef"), in this mode it will provide - cryptographic authentication of the data without encryption. + + In order to provide cryptographic authentication of the data + without encryption, you need: + * the kernel 5.12 and integritysetup 2.3.5 + * specfiy internal_hash as a hmac function with a key, for example + hmac(sha256):0123456789abcdef + * specify journal_hash as a hmac function with a key, for example + hmac(sha256):0123456789abcdef + * specify the fix_hmac argument When this argument is not used, the integrity tags are accepted from an upper layer target, such as dm-crypt. The upper layer -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
