kexec permits the loading and execution of arbitrary code in ring 0, which permits the modification of the running kernel. Prevent this if securelevel has been set. Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx> --- kernel/kexec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 59f7b55..98db2a1 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -32,6 +32,7 @@ #include <linux/vmalloc.h> #include <linux/swap.h> #include <linux/syscore_ops.h> +#include <linux/security.h> #include <asm/page.h> #include <asm/uaccess.h> @@ -942,6 +943,9 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, if (!capable(CAP_SYS_BOOT)) return -EPERM; + if (get_securelevel() > 0) + return -EPERM; + /* * Verify we have a legal set of flags * This leaves us room for future extensions. -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
