From f79d276f2a17ea6c2f536ce6e272dc2754e9271c Mon Sep 17 00:00:00 2001 From: Chun-Yi Lee Date: Wed, 8 Nov 2017 15:11:33 +0000 Subject: [PATCH] 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 Signed-off-by: Chun-Yi Lee Signed-off-by: David Howells Reviewed-by: James Morris cc: kexec@lists.infradead.org Gbp-Pq: Topic features/all/lockdown Gbp-Pq: Name 0008-kexec_file-Restrict-at-runtime-if-the-kernel-is-lock.patch --- kernel/kexec_file.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index c6a3b685137..5644cc8f31a 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -328,6 +328,14 @@ 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; -- 2.30.2