From 97adca80420bc02e5ec7f4f66e80941758c772b1 Mon Sep 17 00:00:00 2001 From: "Lee, Chun-Yi" Date: Wed, 5 Apr 2017 17:40:30 +0100 Subject: [PATCH] kexec_file: Disable at runtime if securelevel has been set When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image through kexec_file systemcall if securelevel has been set. 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: Lee, Chun-Yi Signed-off-by: David Howells Gbp-Pq: Topic features/all/lockdown Gbp-Pq: Name 0046-kexec_file-Disable-at-runtime-if-securelevel-has-bee.patch --- kernel/kexec_file.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 9f48f441229..7da87007c20 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -255,6 +255,12 @@ 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) && kernel_is_locked_down()) + return -EPERM; + /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL; -- 2.30.2