Hi Mimi,
I've adjusted the patch as below.
David
---
commit bf33218ad2bf04f1b92f5c32499ab906f107864c
Author: Chun-Yi Lee <joeyli.kernel@xxxxxxxxx>
Date: Wed May 24 14:56:03 2017 +0100
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.
This code was showed in Matthew's patch but not in git:
https://lkml.org/lkml/2015/3/13/778
Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Signed-off-by: Chun-Yi Lee <jlee@xxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Reviewed-by: James Morris <james.l.morris@xxxxxxxxxx>
cc: kexec@xxxxxxxxxxxxxxxxxxx
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 9f48f4412297..3ba28fc3fab0 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -255,6 +255,14 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
return -EPERM;
+ /* Don't permit images to be loaded into trusted kernels if we're not
+ * going to verify the signature on them
+ */
+ if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) &&
+ !is_ima_appraise_enabled() &&
+ kernel_is_locked_down("kexec of unsigned images"))
+ return -EPERM;
+
/* Make sure we have a legal set of flags */
if (flags != (flags & KEXEC_FILE_FLAGS))
return -EINVAL;
--
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