From 49fcf732bdae0550721ef73af7c45109ce26b2a9 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 19 Aug 2019 17:17:40 -0700 Subject: lockdown: Enforce module signatures if the kernel is locked down If the kernel is locked down, require that all modules have valid signatures that we can verify. I have adjusted the errors generated: (1) If there's no signature (ENODATA) or we can't check it (ENOPKG, ENOKEY), then: (a) If signatures are enforced then EKEYREJECTED is returned. (b) If there's no signature or we can't check it, but the kernel is locked down then EPERM is returned (this is then consistent with other lockdown cases). (2) If the signature is unparseable (EBADMSG, EINVAL), the signature fails the check (EKEYREJECTED) or a system error occurs (eg. ENOMEM), we return the error we got. Note that the X.509 code doesn't check for key expiry as the RTC might not be valid or might not have been transferred to the kernel's clock yet. [Modified by Matthew Garrett to remove the IMA integration. This will be replaced with integration with the IMA architecture policy patchset.] Signed-off-by: David Howells Signed-off-by: Matthew Garrett Reviewed-by: Kees Cook Cc: Jessica Yu Signed-off-by: James Morris --- security/lockdown/Kconfig | 1 + security/lockdown/lockdown.c | 1 + 2 files changed, 2 insertions(+) (limited to 'security') diff --git a/security/lockdown/Kconfig b/security/lockdown/Kconfig index 7a1d213227a4..e84ddf484010 100644 --- a/security/lockdown/Kconfig +++ b/security/lockdown/Kconfig @@ -1,6 +1,7 @@ config SECURITY_LOCKDOWN_LSM bool "Basic module for enforcing kernel lockdown" depends on SECURITY + select MODULE_SIG if MODULES help Build support for an LSM that enforces a coarse kernel lockdown behaviour. diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 7172ad75496b..d8e42125a5dd 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -18,6 +18,7 @@ static enum lockdown_reason kernel_locked_down; static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_NONE] = "none", + [LOCKDOWN_MODULE_SIGNATURE] = "unsigned module loading", [LOCKDOWN_INTEGRITY_MAX] = "integrity", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", }; -- cgit v1.2.3-59-g8ed1b