From: Dhananjay Phadke dphadke@linux.microsoft.com

fdt_fixup_kaslr_seed() will update given ofnode with random seed value. Source for random seed can be TPM or RNG driver in u-boot or sec firmware (ARM).

Signed-off-by: Dhananjay Phadke dphadke@linux.microsoft.com Signed-off-by: Sean Edmond senaedmond@microsoft.com --- arch/arm/cpu/armv8/sec_firmware.c | 39 +++++++++++-------------------- common/fdt_support.c | 19 +++++++++++++++ drivers/core/ofnode.c | 17 ++++++++++++++ include/dm/ofnode.h | 12 ++++++++++ include/fdt_support.h | 9 +++++++ 5 files changed, 71 insertions(+), 25 deletions(-)

diff --git a/arch/arm/cpu/armv8/sec_firmware.c b/arch/arm/cpu/armv8/sec_firmware.c index c0e8726346..5f04cd8aec 100644 --- a/arch/arm/cpu/armv8/sec_firmware.c +++ b/arch/arm/cpu/armv8/sec_firmware.c @@ -411,46 +411,35 @@ int sec_firmware_init(const void *sec_firmware_img, /* * fdt_fix_kaslr - Add kalsr-seed node in Device tree * @fdt: Device tree - * @eret: 0 in case of error, 1 for success + * @eret: 0 for success */ int fdt_fixup_kaslr(void *fdt) { - int nodeoffset; - int err, ret = 0; - u8 rand[8]; + int ret = 0;

#if defined(CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT) + u8 rand[8]; + ofnode root; + /* Check if random seed generation is supported */ if (sec_firmware_support_hwrng() == false) { printf("WARNING: SEC firmware not running, no kaslr-seed\n"); - return 0; + return -EOPNOTSUPP; }

- err = sec_firmware_get_random(rand, 8); - if (err < 0) { + ret = sec_firmware_get_random(rand, 8); + if (ret < 0) { printf("WARNING: No random number to set kaslr-seed\n"); - return 0; + return ret; }

- err = fdt_check_header(fdt); - if (err < 0) { - printf("fdt_chosen: %s\n", fdt_strerror(err)); - return 0; + ret = root_ofnode_from_fdt(fdt, &root); + if (ret < 0) { + printf("WARNING: Unable to get root ofnode\n"); + return ret; }

- /* find or create "/chosen" node. */ - nodeoffset = fdt_find_or_add_subnode(fdt, 0, "chosen"); - if (nodeoffset < 0) - return 0; - - err = fdt_setprop(fdt, nodeoffset, "kaslr-seed", rand, - sizeof(rand)); - if (err < 0) { - printf("WARNING: can't set kaslr-seed %s.\n", - fdt_strerror(err)); - return 0; - } - ret = 1; + ret = fdt_fixup_kaslr_seed(root, rand, sizeof(rand)); #endif

return ret; diff --git a/common/fdt_support.c b/common/fdt_support.c index 5e49078f8c..52be4375b4 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -631,6 +631,25 @@ void fdt_fixup_ethernet(void *fdt) } }

+int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len) +{ + ofnode chosen; + int ret; + + /* find or create "/chosen" node. */ + ret = ofnode_add_subnode(node, "chosen", &chosen); + if (ret && ret != -EEXIST) + return -ENOENT; + + ret = ofnode_write_prop(chosen, "kaslr-seed", seed, len, true); + if (ret) { + printf("WARNING: can't set kaslr-seed\n"); + return ret; + } + + return 0; +} + int fdt_record_loadable(void *blob, u32 index, const char *name, uintptr_t load_addr, u32 size, uintptr_t entry_point, const char *type, const char *os, const char *arch) diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c index 8df16e56af..4be21133b8 100644 --- a/drivers/core/ofnode.c +++ b/drivers/core/ofnode.c @@ -870,6 +870,23 @@ ofnode oftree_path(oftree tree, const char *path) } }

+int root_ofnode_from_fdt(void *fdt, ofnode *root_node) +{ + oftree tree; + /* If OFNODE_MULTI_TREE is not set, and if fdt is not the control FDT, + * oftree_from_fdt() will return NULL + */ + tree = oftree_from_fdt(fdt); + + if (!oftree_valid(tree)) { + printf("Cannot create oftree\n"); + return -EINVAL; + } + *root_node = oftree_root(tree); + + return 0; +} + const void *ofnode_read_chosen_prop(const char *propname, int *sizep) { ofnode chosen_node; diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h index 0f38b3e736..e79bb62be8 100644 --- a/include/dm/ofnode.h +++ b/include/dm/ofnode.h @@ -901,6 +901,18 @@ ofnode oftree_path(oftree tree, const char *path); */ ofnode oftree_root(oftree tree);

+/** + * root_ofnode_from_fdt() - Gets the root ofnode given an FDT blob. + * Note, this will fail if OFNODE_MULTI_TREE + * is not set. + * + * @fdt: Device tree to use + * @root_node : Root ofnode + * + * Return: 0 if OK, -ve on error + */ +int root_ofnode_from_fdt(void *fdt, ofnode *root_node); + /** * ofnode_read_chosen_prop() - get the value of a chosen property * diff --git a/include/fdt_support.h b/include/fdt_support.h index 2cd8366898..d967118bed 100644 --- a/include/fdt_support.h +++ b/include/fdt_support.h @@ -11,6 +11,7 @@ !defined(USE_HOSTCC)

#include <asm/u-boot.h> +#include <dm/ofnode.h> #include <linux/libfdt.h> #include <abuf.h>

@@ -121,6 +122,14 @@ static inline int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], #endif

void fdt_fixup_ethernet(void *fdt); + +/* + * fdt_fixup_kaslr_seed - Add kaslr-seed node in Device tree + * @node: ofnode + * @eret: 0 for success + */ +int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len); + int fdt_find_and_setprop(void *fdt, const char *node, const char *prop, const void *val, int len, int create); void fdt_fixup_qe_firmware(void *fdt);

From: Dhananjay Phadke dphadke@linux.microsoft.com

Add support for KASLR seed from the RNG device. Invokes dm_rng_read() API to read 8-bytes of random bytes. Performs the FDT fixup using event spy. To enable use CONFIG_KASLR_RNG_SEED

Signed-off-by: Dhananjay Phadke dphadke@linux.microsoft.com Signed-off-by: Drew Kluemke ankluemk@microsoft.com Signed-off-by: Sean Edmond seanedmond@microsoft.com --- common/fdt_support.c | 36 ++++++++++++++++++++++++++++++++++++ lib/Kconfig | 7 +++++++ 2 files changed, 43 insertions(+)

diff --git a/common/fdt_support.c b/common/fdt_support.c index 52be4375b4..09ce582865 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -12,7 +12,10 @@ #include <log.h> #include <mapmem.h> #include <net.h> +#include <rng.h> #include <stdio_dev.h> +#include <dm/device.h> +#include <dm/uclass.h> #include <dm/ofnode.h> #include <linux/ctype.h> #include <linux/types.h> @@ -650,6 +653,39 @@ int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len) return 0; }

+int fdt_rng_kaslr_seed(void *ctx, struct event *event) +{ + u8 rand[8] = {0}; + struct udevice *dev; + int ret; + oftree tree = event->data.ft_fixup.tree; + ofnode root_node = oftree_root(tree); + + ret = uclass_first_device_err(UCLASS_RNG, &dev); + if (ret) { + printf("ERROR: Failed to find RNG device\n"); + return ret; + } + + ret = dm_rng_read(dev, rand, sizeof(rand)); + if (ret) { + printf("ERROR: RNG read failed, ret=%d\n", ret); + return ret; + } + + ret = fdt_fixup_kaslr_seed(root_node, rand, sizeof(rand)); + if (ret) { + printf("ERROR: failed to add kaslr-seed to fdt\n"); + return ret; + } + + return 0; +} + +#if defined(CONFIG_KASLR_RNG_SEED) +EVENT_SPY(EVT_FT_FIXUP, fdt_rng_kaslr_seed); +#endif + int fdt_record_loadable(void *blob, u32 index, const char *name, uintptr_t load_addr, u32 size, uintptr_t entry_point, const char *type, const char *os, const char *arch) diff --git a/lib/Kconfig b/lib/Kconfig index 3926652db6..545a14343e 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -465,6 +465,13 @@ config VPL_TPM for the low-level TPM interface, but only one TPM is supported at a time by the TPM library.

+config KASLR_RNG_SEED + bool "Use RNG driver for KASLR random seed" + depends on DM_RNG + help + This enables support for using the RNG driver as entropy source for + KASLR seed populated in kernel's device tree. + endmenu

menu "Android Verified Boot"

From: Sean Edmond seanedmond@microsoft.com

Required to fix the following compile error when building sandbox: /tmp/cci9ibby.ltrans21.ltrans.o: In function `do_cedit_load': <artificial>:(.text+0x601d): undefined reference to `oftree_dispose'

Signed-off-by: Sean Edmond seanedmond@microsoft.com --- drivers/core/ofnode.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c index 4be21133b8..f7b3f41077 100644 --- a/drivers/core/ofnode.c +++ b/drivers/core/ofnode.c @@ -92,12 +92,6 @@ static oftree oftree_ensure(void *fdt) return tree; }

-void oftree_dispose(oftree tree) -{ - if (of_live_active()) - of_live_free(tree.np); -} - void *ofnode_lookup_fdt(ofnode node) { if (gd->flags & GD_FLG_RELOC) { @@ -195,6 +189,12 @@ static inline int oftree_find(const void *fdt)

#endif /* OFNODE_MULTI_TREE */

+void oftree_dispose(oftree tree) +{ + if (of_live_active()) + of_live_free(tree.np); +} + /** * ofnode_from_tree_offset() - get an ofnode from a tree offset (flat tree) *