Re: [PATCH 08/30] kexec_file: Restrict at runtime if the kernel is locked down

[David Howells]

David Howells <dhowells@xxxxxxxxxx> wrote:

> I'm intending on inserting the attached patch before this one.

And replacing this patch with the attached.

David
---
commit ed0424c531d7dd25adebdec0ee6a78a5784f207a
Author: David Howells <dhowells@xxxxxxxxxx>
Date:   Thu Feb 22 14:01:49 2018 +0000

    kexec_file: Restrict at runtime if the kernel is locked down
    
    When KEXEC_VERIFY_SIG is not enabled, kernel should not load images through
    kexec_file systemcall if the kernel is locked down unless IMA can be used
    to validate the image.
    
    [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]
    
    Signed-off-by: Jiri Bohac <jbohac@xxxxxxx>
    Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
    Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
    cc: Chun-Yi Lee <jlee@xxxxxxxx>
    cc: kexec@xxxxxxxxxxxxxxxxxxx

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index d5931e392050..c47c4de604cd 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -167,6 +167,14 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 		}
 
 		ret = 0;
+		if (is_ima_appraise_enabled())
+			break;
+
+		if (kernel_is_locked_down(reason)) {
+			ret = -EPERM;
+			goto out;
+		}
+
 		break;
 
 		/* All other errors are fatal, including nomem, unparseable