Eric Snowberg 0e66932a9d 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 17:25:05 +02:00
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evm	Revert "evm: Fix memleak in init_desc"	2022-07-21 21:24:14 +02:00
ima	lockdown: Fix kexec lockdown bypass with ima policy	2022-07-29 17:25:05 +02:00
platform_certs	efi: Do not import certificates from UEFI Secure Boot for T2 Macs	2022-06-09 10:23:18 +02:00
digsig.c	ima: enable loading of build time generated key on .ima keyring	2021-04-09 10:40:20 -04:00
digsig_asymmetric.c	ima: fix reference leak in asymmetric_verify()	2022-02-16 12:56:03 +01:00
iint.c	evm: Load EVM key in ima_load_x509() to avoid appraisal	2021-05-21 12:47:04 -04:00
integrity.h	crypto: sha - split sha.h into sha1.h and sha2.h	2020-11-20 14:45:33 +11:00
integrity_audit.c	integrity: check the return value of audit_log_start()	2022-02-16 12:56:03 +01:00
Kconfig	powerpc: Load firmware trusted keys/hashes into kernel keyring	2019-11-13 00:33:23 +11:00
Makefile	powerpc: Load firmware trusted keys/hashes into kernel keyring	2019-11-13 00:33:23 +11:00