Generate random seeds to be used by the non-secure and/or secure OSes for ASLR. The seeds are 64-bit random values exported via the DT properties /chosen/kaslr-seed [1] and /secure-chosen/kaslr-seed, the latter being used by OP-TEE [2].
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... [2] https://github.com/OP-TEE/optee_os/commit/ef262691fe0e
Signed-off-by: Jerome Forissier jerome@forissier.org --- hw/arm/virt.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index c3073b7cf19..1b6f3971bf7 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -77,6 +77,7 @@ #include "hw/acpi/generic_event_device.h" #include "hw/virtio/virtio-iommu.h" #include "hw/char/pl011.h" +#include "qemu/guest-random.h"
#define DEFINE_VIRT_MACHINE_LATEST(major, minor, latest) \ static void virt_##major##_##minor##_class_init(ObjectClass *oc, \ @@ -213,6 +214,18 @@ static bool cpu_type_valid(const char *cpu) return false; }
+static void create_kaslr_seed(VirtMachineState *vms, const char *node) +{ + Error *err = NULL; + uint64_t seed; + + if (qemu_guest_getrandom(&seed, sizeof(seed), &err)) { + error_free(err); + return; + } + qemu_fdt_setprop_u64(vms->fdt, node, "kaslr-seed", seed); +} + static void create_fdt(VirtMachineState *vms) { MachineState *ms = MACHINE(vms); @@ -233,9 +246,11 @@ static void create_fdt(VirtMachineState *vms)
/* /chosen must exist for load_dtb to fill in necessary properties later */ qemu_fdt_add_subnode(fdt, "/chosen"); + create_kaslr_seed(vms, "/chosen");
if (vms->secure) { qemu_fdt_add_subnode(fdt, "/secure-chosen"); + create_kaslr_seed(vms, "/secure-chosen"); }
/* Clock node, for the benefit of the UART. The kernel device tree