From 9e67028e76514a8ee279d7d006dfb8069b5115ab Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Wed, 21 Feb 2018 11:36:32 -0500 Subject: ima: fail signature verification based on policy This patch addresses the fuse privileged mounted filesystems in environments which are unwilling to accept the risk of trusting the signature verification and want to always fail safe, but are for example using a pre-built kernel. This patch defines a new builtin policy named "fail_securely", which can be specified on the boot command line as an argument to "ima_policy=". Signed-off-by: Mimi Zohar Cc: Miklos Szeredi Cc: Seth Forshee Cc: Dongsu Park Cc: Alban Crequy Acked-by: Serge Hallyn Acked-by: "Eric W. Biederman" --- Documentation/admin-guide/kernel-parameters.txt | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'Documentation/admin-guide/kernel-parameters.txt') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1d1d53f85ddd..2cc17dc7ab84 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1525,7 +1525,8 @@ ima_policy= [IMA] The builtin policies to load during IMA setup. - Format: "tcb | appraise_tcb | secure_boot" + Format: "tcb | appraise_tcb | secure_boot | + fail_securely" The "tcb" policy measures all programs exec'd, files mmap'd for exec, and all files opened with the read @@ -1540,6 +1541,11 @@ of files (eg. kexec kernel image, kernel modules, firmware, policy, etc) based on file signatures. + The "fail_securely" policy forces file signature + verification failure also on privileged mounted + filesystems with the SB_I_UNVERIFIABLE_SIGNATURE + flag. + ima_tcb [IMA] Deprecated. Use ima_policy= instead. Load a policy which meets the needs of the Trusted Computing Base. This means IMA will measure all -- cgit v1.2.3