When the system reboots, the rng-seed that the FDT has should be
re-randomized, so that the new boot gets a new seed. Several
architectures require this functionality, so export a function for
injecting a new seed into the given FDT.
Cc: Alistair Francis <alistair.fran...@wdc.com>
Cc: David Gibson <da...@gibson.dropbear.id.au>
Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com>
---
include/sysemu/device_tree.h | 9 +++++++++
softmmu/device_tree.c | 21 +++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index ef060a9759..d552f324b6 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -196,6 +196,15 @@ int qemu_fdt_setprop_sized_cells_from_array(void *fdt,
qdt_tmp); \
})
+
+/**
+ * qemu_fdt_randomize_seeds:
+ * @fdt: device tree blob
+ *
+ * Re-randomize all "rng-seed" properties with new seeds.
+ */
+void qemu_fdt_randomize_seeds(void *fdt);
+
#define FDT_PCI_RANGE_RELOCATABLE 0x80000000
#define FDT_PCI_RANGE_PREFETCHABLE 0x40000000
#define FDT_PCI_RANGE_ALIASED 0x20000000
diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index 6ca3fad285..d986c7b7b3 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -22,6 +22,7 @@
#include "qemu/option.h"
#include "qemu/bswap.h"
#include "qemu/cutils.h"
+#include "qemu/guest-random.h"
#include "sysemu/device_tree.h"
#include "hw/loader.h"
#include "hw/boards.h"
@@ -643,3 +644,23 @@ out:
g_free(propcells);
return ret;
}
+
+void qemu_fdt_randomize_seeds(void *fdt)
+{
+ int noffset, poffset, len;
+ const char *name;
+ uint8_t *data;
+
+ for (noffset = fdt_next_node(fdt, 0, NULL);
+ noffset >= 0;
+ noffset = fdt_next_node(fdt, noffset, NULL)) {
+ for (poffset = fdt_first_property_offset(fdt, noffset);
+ poffset >= 0;
+ poffset = fdt_next_property_offset(fdt, poffset)) {
+ data = (uint8_t *)fdt_getprop_by_offset(fdt, poffset, &name, &len);
+ if (!data || strcmp(name, "rng-seed"))
+ continue;
+ qemu_guest_getrandom_nofail(data, len);
+ }
+ }
+}
--
2.37.3
