Eric Snowberg ab5050fd74 lockdown: Fix kexec lockdown bypass with ima policy ... commit 543ce63b66 upstream. The lockdown LSM is primarily used in conjunction with UEFI Secure Boot. This LSM may also be used on machines without UEFI. It can also be enabled when UEFI Secure Boot is disabled. One of lockdown's features is to prevent kexec from loading untrusted kernels. Lockdown can be enabled through a bootparam or after the kernel has booted through securityfs. If IMA appraisal is used with the "ima_appraise=log" boot param, lockdown can be defeated with kexec on any machine when Secure Boot is disabled or unavailable. IMA prevents setting "ima_appraise=log" from the boot param when Secure Boot is enabled, but this does not cover cases where lockdown is used without Secure Boot. To defeat lockdown, boot without Secure Boot and add ima_appraise=log to the kernel command line; then: $ echo "integrity" > /sys/kernel/security/lockdown $ echo "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig" > \ /sys/kernel/security/ima/policy $ kexec -ls unsigned-kernel Add a call to verify ima appraisal is set to "enforce" whenever lockdown is enabled. This fixes CVE-2022-21505. Cc: stable@vger.kernel.org Fixes: 29d3c1c8df ("kexec: Allow kexec_file() with appropriate IMA policy when locked down") Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: John Haxby <john.haxby@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-07-29 17:19:06 +02:00
..
apparmor	apparmor: fix error check	2021-11-18 14:04:22 +01:00
bpf
integrity	lockdown: Fix kexec lockdown bypass with ima policy	2022-07-29 17:19:06 +02:00
keys	KEYS: fix length validation in keyctl_pkey_params_get_2()	2022-04-08 14:39:50 +02:00
loadpin
lockdown
safesetid
selinux	lsm,selinux: pass flowi_common instead of flowi to the LSM hooks	2022-06-09 10:21:09 +02:00
smack	Fix incorrect type in assignment of ipv6 port for audit	2022-04-08 14:40:31 +02:00
tomoyo	TOMOYO: fix __setup handlers return values	2022-04-08 14:40:18 +02:00
yama
commoncap.c
device_cgroup.c
inode.c
Kconfig	x86/retbleed: Add fine grained Kconfig knobs	2022-07-25 11:26:50 +02:00
Kconfig.hardening
lsm_audit.c
Makefile
min_addr.c
security.c	lsm,selinux: pass flowi_common instead of flowi to the LSM hooks	2022-06-09 10:21:09 +02:00