[PATCH v4 0/3] Add support for efi_rng_protocol

[PATCH v4 0/3] Add support for efi_rng_protocol

[Sughosh Ganu]

The patch series adds support for the EFI_RNG_PROTOCOL routines for
qemu arm64 platform. The getrng routine, used to get the random bytes,
uses the virtio-rng device found on the platform. The protocol, once
installed, can be used by the efi stub in the kernel for getting
random bytes needed for the kaslr feature.

These patches apply on top of the patch series to add random number
generator driver uclass[1]

[1] - https://lists.denx.de/pipermail/u-boot/2019-December/394804.html

Changes since V3:
* Handle review comments from Heinrich Schuchardt related to calling
  EFI_EXIT at the end of the efi_rng_protocol routines using a goto
  label.
* Add a weak function platform_get_rng_device based on review comment
  from Heinrich Schuchardt.

Changes since V2:
* Based on review comments from Heinrich Schuchardt, the rng drivers
  read all the bytes requested in the individual
  drivers. Corresponding changes made in getrng routine to remove the
  loop to read the bytes requested, since that would be handled in the
  drivers.

Changes since V1:
* Handle review comments from Heinrich Schuchardt.
* Change the logic in the getrng routine to implement a loop to read
  the number of bytes requested. This change is needed to handle the
  change in the rng uclass's read function, which now returns the
  number of bytes read, which might be less than the number of bytes
  requested.


Sughosh Ganu (3):
  efi_loader: Add guidcpy function
  efi: qemu: arm64: Add efi_rng_protocol implementation for the platform
  efi_rng_protocol: Install the efi_rng_protocol on the root node

 board/emulation/qemu-arm/qemu-arm.c |  42 ++++++++++++++
 include/efi_loader.h                |   9 +++
 include/efi_rng.h                   |  32 ++++++++++
 lib/efi_loader/Kconfig              |   8 +++
 lib/efi_loader/Makefile             |   1 +
 lib/efi_loader/efi_boottime.c       |   4 +-
 lib/efi_loader/efi_rng.c            | 113 ++++++++++++++++++++++++++++++++++++
 lib/efi_loader/efi_root_node.c      |   4 ++
 8 files changed, 211 insertions(+), 2 deletions(-)
 create mode 100644 include/efi_rng.h
 create mode 100644 lib/efi_loader/efi_rng.c

-- 
2.7.4

[PATCH v4 1/3] efi_loader: Add guidcpy function

[Sughosh Ganu]

Add guidcpy function to copy the source guid to the destination
guid. Use this function instead of memcpy for copying to the
destination guid.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 include/efi_loader.h          | 5 +++++
 lib/efi_loader/efi_boottime.c | 4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 16a1b25..bec7873 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -17,6 +17,11 @@ static inline int guidcmp(const void *g1, const void *g2)
 	return memcmp(g1, g2, sizeof(efi_guid_t));
 }
 
+static inline void *guidcpy(efi_guid_t *dst, const efi_guid_t *src)
+{
+	return memcpy(dst, src, sizeof(*dst));
+}
+
 /* No need for efi loader support in SPL */
 #if CONFIG_IS_ENABLED(EFI_LOADER)
 
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 88a7604..3103a50 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1401,7 +1401,7 @@ static efi_status_t EFIAPI efi_register_protocol_notify(
 	}
 
 	item->event = event;
-	memcpy(&item->protocol, protocol, sizeof(efi_guid_t));
+	guidcpy(&item->protocol, protocol);
 	INIT_LIST_HEAD(&item->handles);
 
 	list_add_tail(&item->link, &efi_register_notify_events);
@@ -1632,7 +1632,7 @@ efi_status_t efi_install_configuration_table(const efi_guid_t *guid,
 		return EFI_OUT_OF_RESOURCES;
 
 	/* Add a new entry */
-	memcpy(&systab.tables[i].guid, guid, sizeof(*guid));
+	guidcpy(&systab.tables[i].guid, guid);
 	systab.tables[i].table = table;
 	systab.nr_tables = i + 1;
 
-- 
2.7.4

[PATCH v4 2/3] efi: qemu: arm64: Add efi_rng_protocol implementation for the platform

[Sughosh Ganu]

Add support for the EFI_RNG_PROTOCOL routines for the qemu arm64
platform. EFI_RNG_PROTOCOL is an uefi boottime service which is
invoked by the efi stub in the kernel for getting random seed for
kaslr.

The routines are platform specific, and use the virtio-rng device on
the platform to get random data.

The feature can be enabled through the following config
CONFIG_EFI_RNG_PROTOCOL

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
---
Changes since V3:
* Handle review comments from Heinrich Schuchardt related to calling
  EFI_EXIT at the end of the efi_rng_protocol routines using a goto
  label.
* Add a weak function platform_get_rng_device based on review comment
  from Heinrich Schuchardt.

 board/emulation/qemu-arm/qemu-arm.c |  42 ++++++++++++++
 include/efi_rng.h                   |  32 +++++++++++
 lib/efi_loader/Kconfig              |   8 +++
 lib/efi_loader/Makefile             |   1 +
 lib/efi_loader/efi_rng.c            | 111 ++++++++++++++++++++++++++++++++++++
 5 files changed, 194 insertions(+)
 create mode 100644 include/efi_rng.h
 create mode 100644 lib/efi_loader/efi_rng.c

diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c
index e1f4709..4e18733 100644
--- a/board/emulation/qemu-arm/qemu-arm.c
+++ b/board/emulation/qemu-arm/qemu-arm.c
@@ -91,3 +91,45 @@ void *board_fdt_blob_setup(void)
 	/* QEMU loads a generated DTB for us at the start of RAM. */
 	return (void *)CONFIG_SYS_SDRAM_BASE;
 }
+
+#if defined(CONFIG_EFI_RNG_PROTOCOL)
+#include <efi_loader.h>
+#include <efi_rng.h>
+
+#include <dm/device-internal.h>
+
+efi_status_t platform_get_rng_device(struct udevice **dev)
+{
+	int ret;
+	efi_status_t status = EFI_DEVICE_ERROR;
+	struct udevice *bus, *devp;
+
+	for (uclass_first_device(UCLASS_VIRTIO, &bus); bus;
+	     uclass_next_device(&bus)) {
+		for (device_find_first_child(bus, &devp); devp;
+		     device_find_next_child(&devp)) {
+			if (device_get_uclass_id(devp) == UCLASS_RNG) {
+				*dev = devp;
+				status = EFI_SUCCESS;
+				break;
+			}
+		}
+	}
+
+	if (status != EFI_SUCCESS) {
+		debug("No rng device found\n");
+		return EFI_DEVICE_ERROR;
+	}
+
+	if (*dev) {
+		ret = device_probe(*dev);
+		if (ret)
+			return EFI_DEVICE_ERROR;
+	} else {
+		debug("Couldn't get child device\n");
+		return EFI_DEVICE_ERROR;
+	}
+
+	return EFI_SUCCESS;
+}
+#endif /* CONFIG_EFI_RNG_PROTOCOL */
diff --git a/include/efi_rng.h b/include/efi_rng.h
new file mode 100644
index 0000000..a46e66d
--- /dev/null
+++ b/include/efi_rng.h
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#if !defined _EFI_RNG_H_
+#define _EFI_RNG_H_
+
+#include <efi.h>
+#include <efi_api.h>
+
+/* EFI random number generation protocol related GUID definitions */
+#define EFI_RNG_PROTOCOL_GUID \
+	EFI_GUID(0x3152bca5, 0xeade, 0x433d, 0x86, 0x2e, \
+		 0xc0, 0x1c, 0xdc, 0x29, 0x1f, 0x44)
+
+#define EFI_RNG_ALGORITHM_RAW \
+	EFI_GUID(0xe43176d7, 0xb6e8, 0x4827, 0xb7, 0x84, \
+		 0x7f, 0xfd, 0xc4, 0xb6, 0x85, 0x61)
+
+struct efi_rng_protocol {
+	efi_status_t (EFIAPI *get_info)(struct efi_rng_protocol *protocol,
+					efi_uintn_t *rng_algorithm_list_size,
+					efi_guid_t *rng_algorithm_list);
+	efi_status_t (EFIAPI *get_rng)(struct efi_rng_protocol *protocol,
+				       efi_guid_t *rng_algorithm,
+				       efi_uintn_t rng_value_length, uint8_t *rng_value);
+};
+
+efi_status_t platform_get_rng_device(struct udevice **dev);
+
+#endif /* _EFI_RNG_H_ */
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index 21ef440..24dde6f 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -120,4 +120,12 @@ config EFI_GRUB_ARM32_WORKAROUND
 	  GRUB prior to version 2.04 requires U-Boot to disable caches. This
 	  workaround currently is also needed on systems with caches that
 	  cannot be managed via CP15.
+
+config EFI_RNG_PROTOCOL
+	bool "EFI_RNG_PROTOCOL support"
+	depends on DM_RNG
+	help
+	  "Support for EFI_RNG_PROTOCOL implementation. Uses the rng
+	   device on the platform"
+
 endif
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 7db4060..04dc864 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -42,3 +42,4 @@ obj-$(CONFIG_PARTITIONS) += efi_disk.o
 obj-$(CONFIG_NET) += efi_net.o
 obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o
 obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o
+obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o
diff --git a/lib/efi_loader/efi_rng.c b/lib/efi_loader/efi_rng.c
new file mode 100644
index 0000000..2e7a148
--- /dev/null
+++ b/lib/efi_loader/efi_rng.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <efi_loader.h>
+#include <efi_rng.h>
+#include <rng.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+__weak efi_status_t platform_get_rng_device(struct udevice **dev)
+{
+	int ret;
+	struct udevice *devp;
+
+	ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+	if (ret) {
+		debug("Unable to get rng device\n");
+		return EFI_DEVICE_ERROR;
+	}
+
+	*dev = devp;
+
+	return EFI_SUCCESS;
+}
+
+static efi_status_t EFIAPI rng_getinfo(struct efi_rng_protocol *this,
+				       efi_uintn_t *rng_algorithm_list_size,
+				       efi_guid_t *rng_algorithm_list)
+{
+	efi_status_t ret = EFI_SUCCESS;
+	efi_guid_t rng_algo_guid = EFI_RNG_ALGORITHM_RAW;
+
+	EFI_ENTRY("%p, %p, %p", this, rng_algorithm_list_size,
+		  rng_algorithm_list);
+
+	if (!this || !rng_algorithm_list_size) {
+		ret = EFI_INVALID_PARAMETER;
+		goto back;
+	}
+
+	if (!rng_algorithm_list ||
+	    *rng_algorithm_list_size < sizeof(*rng_algorithm_list)) {
+		*rng_algorithm_list_size = sizeof(*rng_algorithm_list);
+		ret = EFI_BUFFER_TOO_SMALL;
+		goto back;
+	}
+
+	/*
+	 * For now, use EFI_RNG_ALGORITHM_RAW as the default
+	 * algorithm. If a new algorithm gets added in the
+	 * future through a Kconfig, rng_algo_guid will be set
+	 * based on that Kconfig option
+	 */
+	*rng_algorithm_list_size = sizeof(*rng_algorithm_list);
+	guidcpy(rng_algorithm_list, &rng_algo_guid);
+
+back:
+	return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI getrng(struct efi_rng_protocol *this,
+				  efi_guid_t *rng_algorithm,
+				  efi_uintn_t rng_value_length,
+				  uint8_t *rng_value)
+{
+	int ret;
+	efi_status_t status = EFI_SUCCESS;
+	struct udevice *dev;
+	const efi_guid_t rng_raw_guid = EFI_RNG_ALGORITHM_RAW;
+
+	EFI_ENTRY("%p, %p, %zu, %p", this, rng_algorithm, rng_value_length,
+		  rng_value);
+
+	if (!this || !rng_value || !rng_value_length) {
+		status = EFI_INVALID_PARAMETER;
+		goto back;
+	}
+
+	if (rng_algorithm) {
+		EFI_PRINT("RNG algorithm %pUl\n", rng_algorithm);
+		if (guidcmp(rng_algorithm, &rng_raw_guid)) {
+			status = EFI_UNSUPPORTED;
+			goto back;
+		}
+	}
+
+	ret = platform_get_rng_device(&dev);
+	if (ret != EFI_SUCCESS) {
+		status = EFI_UNSUPPORTED;
+		goto back;
+	}
+
+	ret = dm_rng_read(dev, rng_value, rng_value_length);
+	if (ret < 0) {
+		EFI_PRINT("Rng device read failed\n");
+		status = EFI_DEVICE_ERROR;
+		goto back;
+	}
+
+back:
+	return EFI_EXIT(status);
+}
+
+const struct efi_rng_protocol efi_rng_protocol = {
+	.get_info = rng_getinfo,
+	.get_rng = getrng,
+};
-- 
2.7.4

[PATCH v4 3/3] efi_rng_protocol: Install the efi_rng_protocol on the root node

[Sughosh Ganu]

Install the EFI_RNG_PROTOCOL implementation for it's subsequent use by
the kernel for features like kaslr.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 include/efi_loader.h           | 4 ++++
 lib/efi_loader/efi_rng.c       | 2 ++
 lib/efi_loader/efi_root_node.c | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index bec7873..bfcfa74 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -130,6 +130,7 @@ extern const struct efi_hii_config_routing_protocol efi_hii_config_routing;
 extern const struct efi_hii_config_access_protocol efi_hii_config_access;
 extern const struct efi_hii_database_protocol efi_hii_database;
 extern const struct efi_hii_string_protocol efi_hii_string;
+extern const struct efi_rng_protocol efi_rng_protocol;
 
 uint16_t *efi_dp_str(struct efi_device_path *dp);
 
@@ -175,6 +176,9 @@ extern const efi_guid_t efi_guid_hii_config_access_protocol;
 extern const efi_guid_t efi_guid_hii_database_protocol;
 extern const efi_guid_t efi_guid_hii_string_protocol;
 
+/* GUID of RNG protocol */
+extern const efi_guid_t efi_guid_rng_protocol;
+
 extern unsigned int __efi_runtime_start, __efi_runtime_stop;
 extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop;
 
diff --git a/lib/efi_loader/efi_rng.c b/lib/efi_loader/efi_rng.c
index 2e7a148..d1f5400 100644
--- a/lib/efi_loader/efi_rng.c
+++ b/lib/efi_loader/efi_rng.c
@@ -11,6 +11,8 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+const efi_guid_t efi_guid_rng_protocol = EFI_RNG_PROTOCOL_GUID;
+
 __weak efi_status_t platform_get_rng_device(struct udevice **dev)
 {
 	int ret;
diff --git a/lib/efi_loader/efi_root_node.c b/lib/efi_loader/efi_root_node.c
index f68b0fd..76d18fb 100644
--- a/lib/efi_loader/efi_root_node.c
+++ b/lib/efi_loader/efi_root_node.c
@@ -81,6 +81,10 @@ efi_status_t efi_root_node_register(void)
 			 &efi_guid_hii_config_routing_protocol,
 			 (void *)&efi_hii_config_routing,
 #endif
+#if CONFIG_IS_ENABLED(EFI_RNG_PROTOCOL)
+			 &efi_guid_rng_protocol,
+			 (void *)&efi_rng_protocol,
+#endif
 			 NULL));
 	efi_root->type = EFI_OBJECT_TYPE_U_BOOT_FIRMWARE;
 	return ret;
-- 
2.7.4

[PATCH v4 0/3] Add support for efi_rng_protocol

[Heinrich Schuchardt]

On 12/28/19 7:31 PM, Sughosh Ganu wrote:
> The patch series adds support for the EFI_RNG_PROTOCOL routines for
> qemu arm64 platform. The getrng routine, used to get the random bytes,
> uses the virtio-rng device found on the platform. The protocol, once
> installed, can be used by the efi stub in the kernel for getting
> random bytes needed for the kaslr feature.
>
> These patches apply on top of the patch series to add random number
> generator driver uclass[1]
>
> [1] - https://lists.denx.de/pipermail/u-boot/2019-December/394804.html
>
> Changes since V3:
> * Handle review comments from Heinrich Schuchardt related to calling
>    EFI_EXIT at the end of the efi_rng_protocol routines using a goto
>    label.
> * Add a weak function platform_get_rng_device based on review comment
>    from Heinrich Schuchardt.
>
> Changes since V2:
> * Based on review comments from Heinrich Schuchardt, the rng drivers
>    read all the bytes requested in the individual
>    drivers. Corresponding changes made in getrng routine to remove the
>    loop to read the bytes requested, since that would be handled in the
>    drivers.
>
> Changes since V1:
> * Handle review comments from Heinrich Schuchardt.
> * Change the logic in the getrng routine to implement a loop to read
>    the number of bytes requested. This change is needed to handle the
>    change in the rng uclass's read function, which now returns the
>    number of bytes read, which might be less than the number of bytes
>    requested.
>
>
> Sughosh Ganu (3):
>    efi_loader: Add guidcpy function
>    efi: qemu: arm64: Add efi_rng_protocol implementation for the platform
>    efi_rng_protocol: Install the efi_rng_protocol on the root node
>
>   board/emulation/qemu-arm/qemu-arm.c |  42 ++++++++++++++
>   include/efi_loader.h                |   9 +++
>   include/efi_rng.h                   |  32 ++++++++++
>   lib/efi_loader/Kconfig              |   8 +++
>   lib/efi_loader/Makefile             |   1 +
>   lib/efi_loader/efi_boottime.c       |   4 +-
>   lib/efi_loader/efi_rng.c            | 113 ++++++++++++++++++++++++++++++++++++
>   lib/efi_loader/efi_root_node.c      |   4 ++
>   8 files changed, 211 insertions(+), 2 deletions(-)
>   create mode 100644 include/efi_rng.h
>   create mode 100644 lib/efi_loader/efi_rng.c
>

After fixing the buffer overrun in the virtio_rng.c driver your code
passes the EDK II SCT tests without problems on qemu_arm64_defconfig.

Thanks for all the effort you have put into this.

Best regards

Heinrich