luks: limit max entropy bits for pwmake

Resolves: rhbz#2159735

Signed-off-by: Sergio Arroutbi <sarroutb@redhat.com>

0012-luks-define-max-entropy-bits-for-pwmake.patch

@@ -0,0 +1,42 @@
+--- clevis-18.ori/src/clevis.1.adoc	2021-04-15 13:00:19.965065700 +0200
++++ clevis-18/src/clevis.1.adoc	2023-01-13 12:08:31.162012856 +0100
+@@ -101,7 +101,7 @@
+ 
+ This command performs four steps:
+ 
+-1. Creates a new key with the same entropy as the LUKS master key.
++1. Creates a new key with the same entropy as the LUKS master key -- maximum entropy bits is 256.
+ 2. Encrypts the new key with Clevis.
+ 3. Stores the Clevis JWE in the LUKS header.
+ 4. Enables the new key for use with LUKS.
+--- clevis-18.ori/src/luks/clevis-luks-bind.1.adoc	2023-01-13 12:02:52.005243591 +0100
++++ clevis-18/src/luks/clevis-luks-bind.1.adoc	2023-01-13 12:08:05.873955501 +0100
+@@ -20,7 +20,7 @@
+ 
+ This command performs four steps:
+ 
+-1. Creates a new key with the same entropy as the LUKS master key.
++1. Creates a new key with the same entropy as the LUKS master key -- maximum entropy bits is 256.
+ 2. Encrypts the new key with Clevis.
+ 3. Stores the Clevis JWE in the LUKS header.
+ 4. Enables the new key for use with LUKS.
+--- clevis-18.ori/src/luks/clevis-luks-common-functions.in	2023-01-13 12:02:52.005243591 +0100
++++ clevis-18/src/luks/clevis-luks-common-functions.in	2023-01-13 12:06:29.233736316 +0100
+@@ -875,6 +875,7 @@
+     [ -z "${DEV}" ] && return 1
+ 
+     local dump filter bits
++    local MAX_ENTROPY_BITS=256 # Maximum allowed by pwmake.
+     dump=$(cryptsetup luksDump "${DEV}")
+     if cryptsetup isLuks --type luks1 "${DEV}"; then
+         filter="$(echo "${dump}" | sed -rn 's|MK bits:[ \t]*([0-9]+)|\1|p')"
+@@ -886,6 +887,9 @@
+     fi
+ 
+     bits="$(echo -n "${filter}" | sort -n | tail -n 1)"
++    if [ "${bits}" -gt "${MAX_ENTROPY_BITS}" ]; then
++        bits="${MAX_ENTROPY_BITS}"
++    fi
+     pwmake "${bits}"
+ }
+ 

clevis.spec

@@ -1,6 +1,6 @@
 Name:           clevis
 Version:        18
-Release:        108%{?dist}
+Release:        109%{?dist}
 Summary:        Automated decryption framework
 
 License:        GPLv3+
@@ -18,6 +18,7 @@ Patch0008: 0008-Improve-boot-performance-by-removing-key-check.patch
 Patch0009: 0009-luks-enable-debugging-in-clevis-scripts-when-rd.debu.patch
 Patch0010: 0010-existing-luks2-token-id.patch
 Patch0011: 0011-ignore-empty-and-comment-lines-in-crypttab.patch
+Patch0012: 0012-luks-define-max-entropy-bits-for-pwmake.patch
 
 BuildRequires:  git-core
 BuildRequires:  gcc
@@ -198,6 +199,10 @@ systemctl preset %{name}-luks-askpass.path >/dev/null 2>&1 || :
 %attr(4755, root, root) %{_libexecdir}/%{name}-luks-udisks2
 
 %changelog
+* Fri Jan 13 2023 Sergio Arroutbi <sarroutb@redhat.com> - 15-109
+- luks: define max entropy bits for pwmake
+  Resolves: rhbz#2159735
+
 * Thu Jan 12 2023 Sergio Arroutbi <sarroutb@redhat.com> - 15-108
 - Ignore empty & comment lines in crypttab
   Resolves: rhbz#2159728