[PATCH v6 0/5] Populate kaslr seed with RNG

[PATCH v6 0/5] Populate kaslr seed with RNG

[Sean Edmond]

This patch series creates a common API (fdt_fixup_kaslr_seed()) for
populating the kaslr seed in the DTB.  Existing users (kaslrseed,
and ARMv8 sec firmware) have been updated to use this common API.

New functionality has been introduced to populate the kaslr using
the RNG.  This can be enabled with CONFIG_RNG_TPM_SEED.

Changes in v6:
- root_ofnode_from_fdt()->ofnode_root_from_fdt()
- Enclose fdt_rng_kaslr_seed() in "#if defined(CONFIG_KASLR_RNG_SEED)"

Changes in v5:
- include dm/ofnode-decl.h instead of dm/ofnode.h
- cast buffer to (u8 *) in kaslrseed.c
- Always enable OFNODE_MULTI_TREE

Changes in v4:
- Fix compile issue when CONFIG_OF_CONTROL not set

Changes in v3:
- Use event spy to do the FDT fixup
- Populate with RNG device instead of TPM device (this is a more generic solution)
- fix compile error for sandbox for !OFNODE_MULTI_TREE

Changes in v2:
- fdt_fixup_kaslr_seed() uses the ofnode API
- Add root_ofnode_from_fdt() to get the root node from an FDT and
  perform error checking on the oftree
- add comments to exported functions
- Add error checking in image_setup_libfdt() for return from
  fdt_tpm_kaslr_seed()
- uclass_get_device() -> uclass_first_device_err()
- Change default config for OFNODE_MULTI_TREE (y if !OF_LIVE)

Dhananjay Phadke (2):
  fdt: common API to populate kaslr seed
  fdt: kaslr seed from RNG device

Sean Edmond (3):
  cmd: kaslrseed: Use common API to fixup FDT
  dm: core: Modify default for OFNODE_MULTI_TREE
  fdt: Fix compile error for !OFNODE_MULTI_TREE

 arch/arm/cpu/armv8/sec_firmware.c | 39 ++++++++--------------
 boot/fdt_support.c                | 54 +++++++++++++++++++++++++++++++
 cmd/kaslrseed.c                   | 20 ++++--------
 configs/sandbox_defconfig         |  2 +-
 drivers/core/Kconfig              |  3 +-
 drivers/core/ofnode.c             | 29 +++++++++++++----
 include/dm/ofnode.h               | 12 +++++++
 include/fdt_support.h             |  9 ++++++
 lib/Kconfig                       |  7 ++++
 9 files changed, 129 insertions(+), 46 deletions(-)

-- 
2.42.0

[PATCH v6 1/5] fdt: common API to populate kaslr seed

[Sean Edmond]

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>

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
---

Changes in v6:
- root_ofnode_from_fdt()->ofnode_root_from_fdt()

Changes in v5:
- include dm/ofnode-decl.h instead of dm/ofnode.h

Changes in v3:
- Use event spy to do the FDT fixup

Changes in v2:
- fdt_fixup_kaslr_seed() uses the ofnode API
- Add root_ofnode_from_fdt() to get the root node from an FDT and
  perform error checking on the oftree
- add comments to exported functions

 arch/arm/cpu/armv8/sec_firmware.c | 39 +++++++++++--------------------
 boot/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 c0e8726346f..5f256939277 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 = ofnode_root_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/boot/fdt_support.c b/boot/fdt_support.c
index b15d07765fe..49d14a949be 100644
--- a/boot/fdt_support.c
+++ b/boot/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 f72ea416cf1..557a4a1b969 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -966,6 +966,23 @@ ofnode oftree_path(oftree tree, const char *path)
 	}
 }
 
+int ofnode_root_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 5795115c490..b3bb133df19 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -936,6 +936,18 @@ ofnode oftree_path(oftree tree, const char *path);
  */
 ofnode oftree_root(oftree tree);
 
+/**
+ * ofnode_root_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 ofnode_root_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 2cd83668982..0624650dcee 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_decl.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);
-- 
2.42.0

[PATCH v6 2/5] fdt: kaslr seed from RNG device

[Sean Edmond]

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>
Reviewed-by: Simon Glass <sjg@chromium.org>

BAH

---

Changes in v6:
- Enclose fdt_rng_kaslr_seed() in "#if defined(CONFIG_KASLR_RNG_SEED)"

Changes in v3:
- Populate with RNG device instead of TPM device (this is a more generic solution)

Changes in v2:
- Add error checking in image_setup_libfdt() for return from
  fdt_tpm_kaslr_seed()
- uclass_get_device() -> uclass_first_device_err()

 boot/fdt_support.c        | 35 +++++++++++++++++++++++++++++++++++
 configs/sandbox_defconfig |  2 +-
 lib/Kconfig               |  7 +++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/boot/fdt_support.c b/boot/fdt_support.c
index 49d14a949be..b51154f83a5 100644
--- a/boot/fdt_support.c
+++ b/boot/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 +653,38 @@ int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len)
 	return 0;
 }
 
+#if defined(CONFIG_KASLR_RNG_SEED)
+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;
+}
+EVENT_SPY_FULL(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/configs/sandbox_defconfig b/configs/sandbox_defconfig
index bc5bcb2a623..b71790e1532 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -348,4 +348,4 @@ CONFIG_EFI_SECURE_BOOT=y
 CONFIG_TEST_FDTDEC=y
 CONFIG_UNIT_TEST=y
 CONFIG_UT_TIME=y
-CONFIG_UT_DM=y
+CONFIG_UT_DM=y
\ No newline at end of file
diff --git a/lib/Kconfig b/lib/Kconfig
index 19649517a39..4f5dfc00d6f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -477,6 +477,13 @@ 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"
-- 
2.42.0

[PATCH v6 3/5] cmd: kaslrseed: Use common API to fixup FDT

[Sean Edmond]

Use the newly introduced common API fdt_fixup_kaslr_seed() in the
kaslrseed command.

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

---

Changes in v6:
- root_ofnode_from_fdt()->ofnode_root_from_fdt()
- "goto CMD_RET_FAILURE" -> "return CMD_RET_FAILURE"

Changes in v5:
- cast buffer to (u8 *) in kaslrseed.c

 cmd/kaslrseed.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/cmd/kaslrseed.c b/cmd/kaslrseed.c
index 9acb8e16386..9339d82649b 100644
--- a/cmd/kaslrseed.c
+++ b/cmd/kaslrseed.c
@@ -19,7 +19,7 @@ static int do_kaslr_seed(struct cmd_tbl *cmdtp, int flag, int argc, char *const
 	size_t n = 0x8;
 	struct udevice *dev;
 	u64 *buf;
-	int nodeoffset;
+	ofnode root;
 	int ret = CMD_RET_SUCCESS;
 
 	if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
@@ -45,21 +45,15 @@ static int do_kaslr_seed(struct cmd_tbl *cmdtp, int flag, int argc, char *const
 		return CMD_RET_FAILURE;
 	}
 
-	ret = fdt_check_header(working_fdt);
-	if (ret < 0) {
-		printf("fdt_chosen: %s\n", fdt_strerror(ret));
+	ret = ofnode_root_from_fdt(working_fdt, &root);
+	if (ret) {
+		printf("ERROR: Unable to get root ofnode\n");
 		return CMD_RET_FAILURE;
 	}
 
-	nodeoffset = fdt_find_or_add_subnode(working_fdt, 0, "chosen");
-	if (nodeoffset < 0) {
-		printf("Reading chosen node failed\n");
-		return CMD_RET_FAILURE;
-	}
-
-	ret = fdt_setprop(working_fdt, nodeoffset, "kaslr-seed", buf, sizeof(buf));
-	if (ret < 0) {
-		printf("Unable to set kaslr-seed on chosen node: %s\n", fdt_strerror(ret));
+	ret = fdt_fixup_kaslr_seed(root, (u8 *)buf, sizeof(buf));
+	if (ret) {
+		printf("ERROR: failed to add kaslr-seed to fdt\n");
 		return CMD_RET_FAILURE;
 	}
 
-- 
2.42.0

[PATCH v6 4/5] dm: core: Modify default for OFNODE_MULTI_TREE

[Sean Edmond]

There is a preference to use the "ofnode" API for FDT fixups
moving forward.  The FDT fixup will usually be for the kernel FDT.  To
fixup the kernel FDT with the ofnode API, it's required to set the
OFNODE_MULTI_TREE option.

To ensure existing users of kaslr fdt fixup are not impacted, Let's modify
the default value for OFNODE_MULTI_TREE to ensure it's always set.
This will cause a 1007 byte increase in the code size.

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

---

(no changes since v5)

Changes in v5:
- Always enable OFNODE_MULTI_TREE

Changes in v4:
- Fix compile issue when CONFIG_OF_CONTROL not set

Changes in v2:
- Change default config for OFNODE_MULTI_TREE (y if !OF_LIVE)

 drivers/core/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 737d4590d5b..c01a8dc7e0a 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -423,7 +423,8 @@ config DM_DEV_READ_INLINE
 
 config OFNODE_MULTI_TREE
 	bool "Allow the ofnode interface to access any tree"
-	default y if EVENT && !DM_DEV_READ_INLINE && !DM_INLINE_OFNODE
+	depends on OF_CONTROL
+	default y
 	help
 	  Normally U-Boot makes use of its control FDT, the one used to bind
 	  devices and provide options. In some cases, U-Boot must also process
-- 
2.42.0

[PATCH v6 5/5] fdt: Fix compile error for !OFNODE_MULTI_TREE

[Sean Edmond]

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>
Reviewed-by: Simon Glass <sjg@chromium.org>

---

(no changes since v3)

Changes in v3:
- fix compile error for sandbox for !OFNODE_MULTI_TREE

 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 557a4a1b969..f4af184a476 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -135,12 +135,6 @@ int oftree_new(oftree *treep)
 	return 0;
 }
 
-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) {
@@ -243,6 +237,12 @@ int oftree_new(oftree *treep)
 
 #endif /* OFNODE_MULTI_TREE */
 
+void oftree_dispose(oftree tree)
+{
+	if (of_live_active())
+		of_live_free(tree.np);
+}
+
 int oftree_to_fdt(oftree tree, struct abuf *buf)
 {
 	int ret;
-- 
2.42.0

Re: [PATCH v6 0/5] Populate kaslr seed with RNG

[Tom Rini]

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On Thu, Nov 30, 2023 at 04:54:39PM -0800, Sean Edmond wrote:

> This patch series creates a common API (fdt_fixup_kaslr_seed()) for
> populating the kaslr seed in the DTB.  Existing users (kaslrseed,
> and ARMv8 sec firmware) have been updated to use this common API.
> 
> New functionality has been introduced to populate the kaslr using
> the RNG.  This can be enabled with CONFIG_RNG_TPM_SEED.

This series introduces a fail to build on ls1012afrdm_tfa and others.
Also one of the patches has a double Signed-off-by, please fix that too.

-- 
Tom

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Re: [PATCH v6 0/5] Populate kaslr seed with RNG

[Tom Rini]

[-- Attachment #1: Type: text/plain, Size: 776 bytes --]

On Sat, Dec 16, 2023 at 12:09:49PM -0500, Tom Rini wrote:
> On Thu, Nov 30, 2023 at 04:54:39PM -0800, Sean Edmond wrote:
> 
> > This patch series creates a common API (fdt_fixup_kaslr_seed()) for
> > populating the kaslr seed in the DTB.  Existing users (kaslrseed,
> > and ARMv8 sec firmware) have been updated to use this common API.
> > 
> > New functionality has been introduced to populate the kaslr using
> > the RNG.  This can be enabled with CONFIG_RNG_TPM_SEED.
> 
> This series introduces a fail to build on ls1012afrdm_tfa and others.
> Also one of the patches has a double Signed-off-by, please fix that too.

Also, a large number of platforms grow by over 1kB, see beelink-gtking
for example (and use buildman's size comparison tools).

-- 
Tom

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