[PATCH 2/9][D] UBUNTU: SAUCE: (efi-lockdown) kexec_file: Restrict at runtime if the kernel is locked down

[Seth Forshee]

From: Jiri Bohac <jbohac at suse.cz>

BugLink: https://bugs.launchpad.net/bugs/1884159

When KEXEC_SIG is not enabled, kernel should not load images through
kexec_file systemcall if the kernel is locked down.

[Modified by David Howells to fit with modifications to the previous patch
 and to return -EPERM if the kernel is locked down for consistency with
 other lockdowns. Modified by Matthew Garrett to remove the IMA
 integration, which will be replaced by integrating with the IMA
 architecture policy patches.]

Signed-off-by: Jiri Bohac <jbohac at suse.cz>
Signed-off-by: David Howells <dhowells at redhat.com>
Reviewed-by: Jiri Bohac <jbohac at suse.cz>
cc: kexec at lists.infradead.org
Signed-off-by: Matthew Garrett <matthewgarrett at google.com>
(cherry picked from commit 0534109a5184b15bdec4cb66822894478c689603
 git://git.kernel.org/pub/scm/linux/kernel/git/jwboyer/fedora.git)
Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
---
 kernel/kexec_file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 67f3a866eabe..0cfe4f6f7f85 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -239,6 +239,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 		}
 
 		ret = 0;
+
+		if (kernel_is_locked_down(reason)) {
+			ret = -EPERM;
+			goto out;
+		}
+
 		break;
 
 		/* All other errors are fatal, including nomem, unparseable
-- 
2.27.0