From 09d85f8d8909ec8baa07479ba5777bbca24961f3 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 21 Jan 2021 10:09:32 -0500 Subject: dm integrity: introduce the "fix_hmac" argument The "fix_hmac" argument improves security of internal_hash and journal_mac: - the section number is mixed to the mac, so that an attacker can't copy sectors from one journal section to another journal section - the superblock is protected by journal_mac - a 16-byte salt stored in the superblock is mixed to the mac, so that the attacker can't detect that two disks have the same hmac key and also to disallow the attacker to move sectors from one disk to another Signed-off-by: Mikulas Patocka Reported-by: Daniel Glockner Signed-off-by: Lukas Bulwahn # ReST fix Tested-by: Milan Broz Signed-off-by: Mike Snitzer --- Documentation/admin-guide/device-mapper/dm-integrity.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'Documentation/admin-guide/device-mapper') diff --git a/Documentation/admin-guide/device-mapper/dm-integrity.rst b/Documentation/admin-guide/device-mapper/dm-integrity.rst index 2cc5488acbd9..ef762857da95 100644 --- a/Documentation/admin-guide/device-mapper/dm-integrity.rst +++ b/Documentation/admin-guide/device-mapper/dm-integrity.rst @@ -186,6 +186,17 @@ fix_padding space-efficient. If this option is not present, large padding is used - that is for compatibility with older kernels. +fix_hmac + Improve security of internal_hash and journal_mac: + + - the section number is mixed to the mac, so that an attacker can't + copy sectors from one journal section to another journal section + - the superblock is protected by journal_mac + - a 16-byte salt stored in the superblock is mixed to the mac, so + that the attacker can't detect that two disks have the same hmac + key and also to disallow the attacker to move sectors from one + disk to another + legacy_recalculate Allow recalculating of volumes with HMAC keys. This is disabled by default for security reasons - an attacker could modify the volume, -- cgit v1.2.3