Carry forward IMA measurement log on kexec on ARM64

The function prototype for the functions defined in ima.c for powerpc are given in the header file ima.h. But this header file is not included in ima.c resulting in compilation errors such as given below.

arch/powerpc/kexec/ima.c:56:5: error: no previous prototype for 'ima_get_kexec_buffer' [-Werror=missing-prototypes]
56 | int ima_get_kexec_buffer(void **addr, size_t *size)

      |     ^~~~~~~~~~~~~~~~~~~~

The function parameters for remove_ima_buffer() and arch_ima_add_kexec_buffer() are not described in the function header resulting in warnings such as given below.

arch/powerpc/kexec/ima.c:111: warning: Function parameter or member 'fdt' not described in 'remove_ima_buffer'

Include ima.h in ima.c for powerpc. Describe the function parameters for remove_ima_buffer() and arch_ima_add_kexec_buffer().

Co-developed-by Prakhar Srivastava <[email protected]>

Signed-off-by Prakhar Srivastava <[email protected]>

Signed-off-by Lakshmi Ramasubramanian <[email protected]>

The function do_get_kexec_buffer(), defined in arch/powerpc/kexec/ima.c, retrieves the address and size of the given property from the device tree blob. This function does not have architecture specific code, but is currently limited to powerpc. This function correctly handles a device tree property that is a child node of the root node, but not anything other than the immediate root child nodes.

Define an architecture independent function, namely get_ima_kexec_buffer(), in "drivers/of/ima_kexec.c". This function retrieves the chosen node, namely "linux,ima-kexec-buffer", from

the device tree, and returns the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call.

Quoted 10 lines · Lakshmi Ramasubramanian

The function do_get_kexec_buffer(), defined in arch/powerpc/kexec/ima.c, retrieves the address and size of the given property from the device tree blob. This function does not have architecture specific code, but is currently limited to powerpc. This function correctly handles a device tree property that is a child node of the root node, but not anything other than the immediate root child nodes.

Define an architecture independent function, namely get_ima_kexec_buffer(), in "drivers/of/ima_kexec.c". This function retrieves the chosen node, namely "linux,ima-kexec-buffer", from

Please remove the word "namely", here, and throughout the patch sets.

Quoted 2 lines

the device tree, and returns the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call.

get_ima_kexec_buffer() inlines the existing do_get_kexec_buffer() and get_addr_size_cells() functions, leaving a local copy of
get_addr_size_cells(). Duplicating code isn't a good idea.

ima_get_kexec_buffer() retrieves the address and size of the buffer used for carrying forward the IMA measurement logs on kexec from the device tree.

ima_free_kexec_buffer() removes the chosen node namely "linux,ima-kexec-buffer" from the device tree, and frees the buffer used for carrying forward the IMA measurement logs on kexec.

These functions do not have architecture specific code, but are currently limited to powerpc.

Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima_kexec.c in IMA so that they are accessible for other architectures as well.

With the above change the functions in arch/powerpc/kexec/ima.c are defined only when the kernel config CONFIG_IMA_KEXEC is enabled. Update the Makefile to build arch/powerpc/kexec/ima.c only when CONFIG_IMA_KEXEC is enabled and remove "#ifdef CONFIG_IMA_KEXEC" in arch/powerpc/kexec/ima.c.

Co-developed-by Prakhar Srivastava <[email protected]>

Signed-off-by Prakhar Srivastava <[email protected]>

Signed-off-by Lakshmi Ramasubramanian <[email protected]>

security/integrity/ima/ima_kexec.c +41 -0

index 121de3e04af2..3f0fa2673dd3 100644
@@ -9,9 +9,60 @@
 
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
 #include <linux/kexec.h>
+#include <linux/ima.h>
 #include "ima.h"
 
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr:	On successful return, set to point to the buffer contents.
+ * @size:	On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int ima_get_kexec_buffer(void **addr, size_t *size)
+{
+	int ret;
+	unsigned long tmp_addr;
+	size_t tmp_size;
+
+	ret = get_ima_kexec_buffer(NULL, 0, &tmp_addr, &tmp_size);
+	if (ret)
+		return ret;
+
+	*addr = __va(tmp_addr);
+	*size = tmp_size;
+
+	return 0;
+}
+
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
+ */
+static int ima_free_kexec_buffer(void)
+{
+	int ret;
+	unsigned long addr;
+	size_t size;
+	struct property *prop;
+
+	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
+	if (!prop)
+		return -ENOENT;
+
+	ret = get_ima_kexec_buffer(NULL, 0, &addr, &size);

security/integrity/ima/ima_kexec.c +0 -0

 #ifdef CONFIG_IMA_KEXEC
 static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
 				     unsigned long segment_size)

Hi Lakshmi,

Quoted 8 lines · Lakshmi Ramasubramanian

ima_get_kexec_buffer() retrieves the address and size of the buffer used for carrying forward the IMA measurement logs on kexec from the device tree.

ima_free_kexec_buffer() removes the chosen node namely "linux,ima-kexec-buffer" from the device tree, and frees the buffer used for carrying forward the IMA measurement logs on kexec.

Quoted 5 lines

These functions do not have architecture specific code, but are currently limited to powerpc.

Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima_kexec.c in IMA so that they are accessible for other architectures as well.

This sentence flows from the previous line. No need for separate paragraphs here.

Quoted 10 lines

With the above change the functions in arch/powerpc/kexec/ima.c are defined only when the kernel config CONFIG_IMA_KEXEC is enabled. Update the Makefile to build arch/powerpc/kexec/ima.c only when CONFIG_IMA_KEXEC is enabled and remove "#ifdef CONFIG_IMA_KEXEC" in arch/powerpc/kexec/ima.c.

Co-developed-by Prakhar Srivastava <[email protected]>

Signed-off-by Prakhar Srivastava <[email protected]>

Signed-off-by Lakshmi Ramasubramanian <[email protected]>

After making the two changes,

Reviewed-by Mimi Zohar <[email protected]>

Quoted 57 lines

security/integrity/ima/ima_kexec.c +46 -0

index 121de3e04af2..3f0fa2673dd3 100644
@@ -9,9 +9,60 @@
 
  #include <linux/seq_file.h>
  #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
  #include <linux/kexec.h>
+#include <linux/ima.h>
  #include "ima.h"
 
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr:	On successful return, set to point to the buffer contents.
+ * @size:	On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int ima_get_kexec_buffer(void **addr, size_t *size)
+{
+	int ret;
+	unsigned long tmp_addr;
+	size_t tmp_size;
+
+	ret = get_ima_kexec_buffer(NULL, 0, &tmp_addr, &tmp_size);
+	if (ret)
+		return ret;
+
+	*addr = __va(tmp_addr);
+	*size = tmp_size;
+
+	return 0;
+}
+
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
+ */
+static int ima_free_kexec_buffer(void)
+{
+	int ret;
+	unsigned long addr;
+	size_t size;
+	struct property *prop;
+
+	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
+	if (!prop)
+		return -ENOENT;
+
+	ret = get_ima_kexec_buffer(NULL, 0, &addr, &size);
+	if (ret)
+		return ret;
+
+	ret = of_remove_property(of_chosen, prop);
+	if (ret)

security/integrity/ima/ima_kexec.c line 65

Quoted 5 lines

security/integrity/ima/ima_kexec.c +5 -0

+		return ret;
+
+	return memblock_free(addr, size);
+}
+

Please move these functions, after the ifdef below, before the function where they're used.

Quoted 4 lines

security/integrity/ima/ima_kexec.c +0 -0

  #ifdef CONFIG_IMA_KEXEC
  static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
  				     unsigned long segment_size)

Address and size of the buffer containing the IMA measurement log need to be passed from the current kernel to the next kernel on kexec.

Add address and size fields to "struct kimage_arch" for ARM64 platform to hold the address and size of the IMA measurement log buffer. Define an architecture specific function for ARM64 namely arch_ima_add_kexec_buffer() that will set the address and size of the current kernel's IMA buffer to be passed to the next kernel on kexec.

Co-developed-by Prakhar Srivastava <[email protected]>

Signed-off-by Prakhar Srivastava <[email protected]>

Signed-off-by Lakshmi Ramasubramanian <[email protected]>

Reviewed-by Thiago Jung Bauermann <[email protected]>

---
 arch/arm64/include/asm/ima.h   | 18 ++++++++++++++++++
 arch/arm64/include/asm/kexec.h |  3 +++
 arch/arm64/kernel/Makefile     |  1 +
 arch/arm64/kernel/ima_kexec.c  | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)
 create mode 100644 arch/arm64/include/asm/ima.h
 create mode 100644 arch/arm64/kernel/ima_kexec.c

arch/arm64/include/asm/ima.h new file +18 -0

new file mode 100644
index 000000000000..507fc94ddaba
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019 Microsoft Corporation
+ *
+ * Author: Prakhar Srivastava <[email protected]>
+ *
+ */
+#ifndef _ASM_ARCH_IMA_H
+#define _ASM_ARCH_IMA_H
+
+struct kimage;
+
+#ifdef CONFIG_IMA_KEXEC
+int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
+			      size_t size);
+#endif /* CONFIG_IMA_KEXEC */
+
+#endif /* _ASM_ARCH_IMA_H */

arch/arm64/include/asm/kexec.h +0 -0

index d24b527e8c00..7bd60c185ad3 100644

arch/arm64/kernel/ima_kexec.c new file +24 -0

new file mode 100644
index 000000000000..1847f1230710
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019 Microsoft Corporation
+ *
+ * Author: Prakhar Srivastava <[email protected]>
+ *
+ * File: ima_kexec.c
+ *       Defines IMA kexec functions.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/types.h>
+#include <asm/ima.h>
+
+/**
+ * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
+ *
+ * @image: kimage structure to set ima buffer information in for kexec
+ * @load_addr: Start address of the IMA buffer
+ * @size: size of the IMA buffer
+ *
+ * Architectures should use this function to pass on the IMA buffer
+ * information to the next kernel.

Quoted 53 lines · Lakshmi Ramasubramanian

Address and size of the buffer containing the IMA measurement log need to be passed from the current kernel to the next kernel on kexec.

Add address and size fields to "struct kimage_arch" for ARM64 platform to hold the address and size of the IMA measurement log buffer. Define an architecture specific function for ARM64 namely arch_ima_add_kexec_buffer() that will set the address and size of the current kernel's IMA buffer to be passed to the next kernel on kexec.

Co-developed-by Prakhar Srivastava <[email protected]>

Signed-off-by Prakhar Srivastava <[email protected]>

Signed-off-by Lakshmi Ramasubramanian <[email protected]>

Reviewed-by Thiago Jung Bauermann <[email protected]>

---
  arch/arm64/include/asm/ima.h   | 18 ++++++++++++++++++
  arch/arm64/include/asm/kexec.h |  3 +++
  arch/arm64/kernel/Makefile     |  1 +
  arch/arm64/kernel/ima_kexec.c  | 34 ++++++++++++++++++++++++++++++++++
  4 files changed, 56 insertions(+)

create mode 100644 arch/arm64/include/asm/ima.h create mode 100644 arch/arm64/kernel/ima_kexec.c

arch/arm64/include/asm/ima.h new file +18 -0

new file mode 100644
index 000000000000..507fc94ddaba
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019 Microsoft Corporation
+ *
+ * Author: Prakhar Srivastava <[email protected]>
+ *
+ */
+#ifndef _ASM_ARCH_IMA_H
+#define _ASM_ARCH_IMA_H
+
+struct kimage;
+
+#ifdef CONFIG_IMA_KEXEC
+int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
+			      size_t size);
+#endif /* CONFIG_IMA_KEXEC */
+
+#endif /* _ASM_ARCH_IMA_H */

arch/arm64/include/asm/kexec.h +0 -0

index d24b527e8c00..7bd60c185ad3 100644
@@ -100,6 +100,9 @@ struct kimage_arch {
  	void *elf_headers;
  	unsigned long elf_headers_mem;

arch/arm64/include/asm/kexec.h struct kimage_arch { · line 106

Quoted 5 lines

arch/arm64/include/asm/kexec.h +3 -0

  	unsigned long elf_headers_sz;
+
+	phys_addr_t ima_buffer_addr;
+	size_t ima_buffer_size;
  };

Any reason these definitions are not conditionally defined based on CONFIG_IMA_KEXEC, like on powerpc?

Quoted 37 lines

arch/arm64/kernel/ima_kexec.c new file +29 -0

new file mode 100644
index 000000000000..1847f1230710
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019 Microsoft Corporation
+ *
+ * Author: Prakhar Srivastava <[email protected]>
+ *
+ * File: ima_kexec.c
+ *       Defines IMA kexec functions.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/types.h>
+#include <asm/ima.h>
+
+/**
+ * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
+ *
+ * @image: kimage structure to set ima buffer information in for kexec
+ * @load_addr: Start address of the IMA buffer
+ * @size: size of the IMA buffer
+ *
+ * Architectures should use this function to pass on the IMA buffer
+ * information to the next kernel.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
+			      size_t size)

arch/arm64/kernel/ima_kexec.c line 34

Quoted 5 lines

arch/arm64/kernel/ima_kexec.c new file +5 -0

+{
+	image->arch.ima_buffer_addr = load_addr;
+	image->arch.ima_buffer_size = size;
+	return 0;
+}

This is exactly the same as the powerpc version. Couldn't there be a common version of this as well?

On kexec file load Integrity Measurement Architecture (IMA) subsystem may verify the IMA signature of the kernel and initramfs, and measure it. The command line parameters passed to the kernel in the kexec call may also be measured by IMA. A remote attestation service can verify a TPM quote based on the TPM event log, the IMA measurement list, and the TPM PCR data. This can be achieved only if the IMA measurement log is carried over from the current kernel to the next kernel across the kexec call.

powerpc already supports carrying forward the IMA measurement log on kexec. This patch set adds support for carrying forward the IMA measurement log on kexec on ARM64.

This patch set moves the platform independent code defined for powerpc such that it can be reused for other platforms as well. A chosen node namely "linux,ima-kexec-buffer" is added to the DTB for ARM64 to hold the address and the size of the memory reserved to carry the IMA measurement log.

This patch set has been tested for ARM64 platform using QEMU. I would like help from the community for testing this change on powerpc. Thanks.

This patch set is based on
commit af5043c89a8e ("Merge tag 'acpi-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm")
in https://github.com/torvalds/linux "master" branch.

Changelog:

v9
- Moved delete_fdt_mem_rsv() to drivers/of/kexec_fdt.c
- Defined a new function get_ima_kexec_buffer() in drivers/of/ima_kexec.c to replace do_get_kexec_buffer()
- Changed remove_ima_kexec_buffer() to the original function name remove_ima_buffer()
- Moved remove_ima_buffer() to drivers/of/ima_kexec.c
- Moved ima_get_kexec_buffer() and ima_free_kexec_buffer() to security/integrity/ima/ima_kexec.c

v8:
- Moved remove_ima_kexec_buffer(), do_get_kexec_buffer(), and delete_fdt_mem_rsv() to drivers/of/fdt.c
- Moved ima_dump_measurement_list() and ima_add_kexec_buffer() back to security/integrity/ima/ima_kexec.c

v7:
- Renamed remove_ima_buffer() to remove_ima_kexec_buffer() and moved this function definition to kernel.
- Moved delete_fdt_mem_rsv() definition to kernel
- Moved ima_dump_measurement_list() and ima_add_kexec_buffer() to a new file namely ima_kexec_fdt.c in IMA

v6:
- Remove any existing FDT_PROP_IMA_KEXEC_BUFFER property in the device tree and also its corresponding memory reservation in the currently running kernel.
- Moved the function remove_ima_buffer() defined for powerpc to IMA and renamed the function to ima_remove_kexec_buffer(). Also, moved delete_fdt_mem_rsv() from powerpc to IMA.

v5:
- Merged get_addr_size_cells() and do_get_kexec_buffer() into a single function when moving the arch independent code from powerpc to IMA
- Reverted the change to use FDT functions in powerpc code and added back the original code in get_addr_size_cells() and do_get_kexec_buffer() for powerpc.
- Added fdt_add_mem_rsv() for ARM64 to reserve the memory for the IMA log buffer during kexec.
- Fixed the warning reported by kernel test bot for ARM64 arch_ima_add_kexec_buffer() - moved this function to a new file namely arch/arm64/kernel/ima_kexec.c

v4:
- Submitting the patch series on behalf of the original author Prakhar Srivastava <[email protected]>
- Moved FDT_PROP_IMA_KEXEC_BUFFER ("linux,ima-kexec-buffer") to libfdt.h so that it can be shared by multiple platforms.

v3:
Breakup patches further into separate patches.
- Refactoring non architecture specific code out of powerpc
- Update powerpc related code to use fdt functions
- Update IMA buffer read related code to use of functions
- Add support to store the memory information of the IMA measurement logs to be carried forward.
- Update the property strings to align with documented nodes
https://github.com/devicetree-org/dt-schema/pull/46

v2:
Break patches into separate patches.
- Powerpc related Refactoring
- Updating the docuemntation for chosen node
- Updating arm64 to support IMA buffer pass

v1:
Refactoring carrying over IMA measuremnet logs over Kexec. This patch
moves the non-architecture specific code out of powerpc and adds to security/ima.(Suggested by Thiago)
Add Documentation regarding the ima-kexec-buffer node in the chosen
node documentation

v0:
Add a layer of abstraction to use the memory reserved by device tree
for ima buffer pass.
Add support for ima buffer pass using reserved memory for arm64 kexec.
Update the arch sepcific code path in kexec file load to store the ima buffer in the reserved memory. The same reserved memory is read on kexec or cold boot.

Lakshmi Ramasubramanian (8):
powerpc: fix compiler warnings and errors
powerpc: Move delete_fdt_mem_rsv() to drivers/of
ima: Define get_ima_kexec_buffer() in drivers/of
powerpc: Use get_ima_kexec_buffer to get ima kexec buffer
powerpc: Move remove_ima_buffer() to drivers/of
powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to
ima
arm64: Store IMA log information in kimage used for kexec
arm64: Add IMA kexec buffer to DTB

 arch/arm64/Kconfig                     |   1 +
 arch/arm64/include/asm/ima.h           |  18 +++++
 arch/arm64/include/asm/kexec.h         |   3 +
 arch/arm64/kernel/Makefile             |   1 +
 arch/arm64/kernel/ima_kexec.c          |  34 ++++++++
 arch/arm64/kernel/machine_kexec_file.c |  18 +++++
 arch/powerpc/include/asm/ima.h         |  11 +--
 arch/powerpc/include/asm/kexec.h       |   1 -
 arch/powerpc/kexec/Makefile            |   7 +-
 arch/powerpc/kexec/file_load.c         |  32 --------
 arch/powerpc/kexec/ima.c               | 106 ++-----------------------
 drivers/of/Makefile                    |   9 +++

 drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
 drivers/of/kexec_fdt.c                 |  55 +++++++++++++

 include/linux/kexec.h                  |  24 ++++++
 security/integrity/ima/ima_kexec.c     |  51 ++++++++++++
 16 files changed, 313 insertions(+), 149 deletions(-)
 create mode 100644 arch/arm64/include/asm/ima.h
 create mode 100644 arch/arm64/kernel/ima_kexec.c
 create mode 100644 drivers/of/ima_kexec.c
 create mode 100644 drivers/of/kexec_fdt.c

Signature · 1 line

2.29.2

Quoted 19 lines · Lakshmi Ramasubramanian

On kexec file load Integrity Measurement Architecture (IMA) subsystem may verify the IMA signature of the kernel and initramfs, and measure it. The command line parameters passed to the kernel in the kexec call may also be measured by IMA. A remote attestation service can verify a TPM quote based on the TPM event log, the IMA measurement list, and the TPM PCR data. This can be achieved only if the IMA measurement log is carried over from the current kernel to the next kernel across the kexec call.

powerpc already supports carrying forward the IMA measurement log on kexec. This patch set adds support for carrying forward the IMA measurement log on kexec on ARM64.

This patch set moves the platform independent code defined for powerpc such that it can be reused for other platforms as well. A chosen node namely "linux,ima-kexec-buffer" is added to the DTB for ARM64 to hold the address and the size of the memory reserved to carry the IMA measurement log.

Quoted 3 lines

This patch set has been tested for ARM64 platform using QEMU. I would like help from the community for testing this change on powerpc. Thanks.

As I mentioned previously, please move the kexec code to drivers/of/. Or at least put the infrastructure in place so we're not defining public IMA functions and then making them static later.

Quoted 110 lines

This patch set is based on
commit af5043c89a8e ("Merge tag 'acpi-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm")
in https://github.com/torvalds/linux "master" branch.

Changelog:

v9
- Moved delete_fdt_mem_rsv() to drivers/of/kexec_fdt.c
- Defined a new function get_ima_kexec_buffer() in drivers/of/ima_kexec.c to replace do_get_kexec_buffer()
- Changed remove_ima_kexec_buffer() to the original function name remove_ima_buffer()
- Moved remove_ima_buffer() to drivers/of/ima_kexec.c
- Moved ima_get_kexec_buffer() and ima_free_kexec_buffer() to security/integrity/ima/ima_kexec.c

v8:
- Moved remove_ima_kexec_buffer(), do_get_kexec_buffer(), and delete_fdt_mem_rsv() to drivers/of/fdt.c
- Moved ima_dump_measurement_list() and ima_add_kexec_buffer() back to security/integrity/ima/ima_kexec.c

v7:
- Renamed remove_ima_buffer() to remove_ima_kexec_buffer() and moved this function definition to kernel.
- Moved delete_fdt_mem_rsv() definition to kernel
- Moved ima_dump_measurement_list() and ima_add_kexec_buffer() to a new file namely ima_kexec_fdt.c in IMA

v6:
- Remove any existing FDT_PROP_IMA_KEXEC_BUFFER property in the device tree and also its corresponding memory reservation in the currently running kernel.
- Moved the function remove_ima_buffer() defined for powerpc to IMA and renamed the function to ima_remove_kexec_buffer(). Also, moved delete_fdt_mem_rsv() from powerpc to IMA.

v5:
- Merged get_addr_size_cells() and do_get_kexec_buffer() into a single function when moving the arch independent code from powerpc to IMA
- Reverted the change to use FDT functions in powerpc code and added back the original code in get_addr_size_cells() and do_get_kexec_buffer() for powerpc.
- Added fdt_add_mem_rsv() for ARM64 to reserve the memory for the IMA log buffer during kexec.
- Fixed the warning reported by kernel test bot for ARM64 arch_ima_add_kexec_buffer() - moved this function to a new file namely arch/arm64/kernel/ima_kexec.c

v4:
- Submitting the patch series on behalf of the original author Prakhar Srivastava <[email protected]>
- Moved FDT_PROP_IMA_KEXEC_BUFFER ("linux,ima-kexec-buffer") to libfdt.h so that it can be shared by multiple platforms.

v3:
Breakup patches further into separate patches.
- Refactoring non architecture specific code out of powerpc
- Update powerpc related code to use fdt functions
- Update IMA buffer read related code to use of functions
- Add support to store the memory information of the IMA measurement logs to be carried forward.
- Update the property strings to align with documented nodes
https://github.com/devicetree-org/dt-schema/pull/46

v2:
Break patches into separate patches.
- Powerpc related Refactoring
- Updating the docuemntation for chosen node
- Updating arm64 to support IMA buffer pass

v1:
Refactoring carrying over IMA measuremnet logs over Kexec. This patch
moves the non-architecture specific code out of powerpc and adds to security/ima.(Suggested by Thiago)
Add Documentation regarding the ima-kexec-buffer node in the chosen
node documentation

v0:
Add a layer of abstraction to use the memory reserved by device tree
for ima buffer pass.
Add support for ima buffer pass using reserved memory for arm64 kexec.
Update the arch sepcific code path in kexec file load to store the ima buffer in the reserved memory. The same reserved memory is read on kexec or cold boot.

Lakshmi Ramasubramanian (8):
powerpc: fix compiler warnings and errors
powerpc: Move delete_fdt_mem_rsv() to drivers/of
ima: Define get_ima_kexec_buffer() in drivers/of
powerpc: Use get_ima_kexec_buffer to get ima kexec buffer
powerpc: Move remove_ima_buffer() to drivers/of
powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to
ima
arm64: Store IMA log information in kimage used for kexec
arm64: Add IMA kexec buffer to DTB

  arch/arm64/Kconfig                     |   1 +
  arch/arm64/include/asm/ima.h           |  18 +++++
  arch/arm64/include/asm/kexec.h         |   3 +
  arch/arm64/kernel/Makefile             |   1 +
  arch/arm64/kernel/ima_kexec.c          |  34 ++++++++
  arch/arm64/kernel/machine_kexec_file.c |  18 +++++
  arch/powerpc/include/asm/ima.h         |  11 +--
  arch/powerpc/include/asm/kexec.h       |   1 -
  arch/powerpc/kexec/Makefile            |   7 +-
  arch/powerpc/kexec/file_load.c         |  32 --------
  arch/powerpc/kexec/ima.c               | 106 ++-----------------------
  drivers/of/Makefile                    |   9 +++

Quoted 2 lines

  drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
  drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Quoted 12 lines

  include/linux/kexec.h                  |  24 ++++++
  security/integrity/ima/ima_kexec.c     |  51 ++++++++++++
  16 files changed, 313 insertions(+), 149 deletions(-)

create mode 100644 arch/arm64/include/asm/ima.h create mode 100644 arch/arm64/kernel/ima_kexec.c create mode 100644 drivers/of/ima_kexec.c create mode 100644 drivers/of/kexec_fdt.c

Signature · 1 line

2.29.2

Quoted 20 lines · Rob Herring

Quoted 19 lines · Lakshmi Ramasubramanian

On kexec file load Integrity Measurement Architecture (IMA) subsystem may verify the IMA signature of the kernel and initramfs, and measure it. The command line parameters passed to the kernel in the kexec call may also be measured by IMA. A remote attestation service can verify a TPM quote based on the TPM event log, the IMA measurement list, and the TPM PCR data. This can be achieved only if the IMA measurement log is carried over from the current kernel to the next kernel across the kexec call.

powerpc already supports carrying forward the IMA measurement log on kexec. This patch set adds support for carrying forward the IMA measurement log on kexec on ARM64.

This patch set moves the platform independent code defined for powerpc such that it can be reused for other platforms as well. A chosen node namely "linux,ima-kexec-buffer" is added to the DTB for ARM64 to hold the address and the size of the memory reserved to carry the IMA measurement log.

Quoted 7 lines

Quoted 3 lines

This patch set has been tested for ARM64 platform using QEMU. I would like help from the community for testing this change on powerpc. Thanks.

As I mentioned previously, please move the kexec code to drivers/of/. Or at least put the infrastructure in place so we're not defining public IMA functions and then making them static later.

I am not sure I am following you. Could you please clarify -
In this patch series, per your suggestion, I have moved the architecture independent kexec code to "drivers/of".

    => drivers/of/ima_kexec.c
    => drivers/of/kexec_fdt.c

Please let me know if I missed something.

Quoted 110 lines

Quoted 109 lines

This patch set is based on
commit af5043c89a8e ("Merge tag 'acpi-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm")
in https://github.com/torvalds/linux "master" branch.

Changelog:

v9
   - Moved delete_fdt_mem_rsv() to drivers/of/kexec_fdt.c
   - Defined a new function get_ima_kexec_buffer() in drivers/of/ima_kexec.c to replace do_get_kexec_buffer()
   - Changed remove_ima_kexec_buffer() to the original function name remove_ima_buffer()
   - Moved remove_ima_buffer() to drivers/of/ima_kexec.c
   - Moved ima_get_kexec_buffer() and ima_free_kexec_buffer() to security/integrity/ima/ima_kexec.c

v8:
   - Moved remove_ima_kexec_buffer(), do_get_kexec_buffer(), and delete_fdt_mem_rsv() to drivers/of/fdt.c
   - Moved ima_dump_measurement_list() and ima_add_kexec_buffer() back to security/integrity/ima/ima_kexec.c

v7:
   - Renamed remove_ima_buffer() to remove_ima_kexec_buffer() and moved this function definition to kernel.
   - Moved delete_fdt_mem_rsv() definition to kernel
   - Moved ima_dump_measurement_list() and ima_add_kexec_buffer() to a new file namely ima_kexec_fdt.c in IMA

v6:
   - Remove any existing FDT_PROP_IMA_KEXEC_BUFFER property in the device tree and also its corresponding memory reservation in the currently running kernel.
   - Moved the function remove_ima_buffer() defined for powerpc to IMA and renamed the function to ima_remove_kexec_buffer(). Also, moved delete_fdt_mem_rsv() from powerpc to IMA.

v5:
   - Merged get_addr_size_cells() and do_get_kexec_buffer() into a single function when moving the arch independent code from powerpc to IMA
   - Reverted the change to use FDT functions in powerpc code and added back the original code in get_addr_size_cells() and do_get_kexec_buffer() for powerpc.
   - Added fdt_add_mem_rsv() for ARM64 to reserve the memory for the IMA log buffer during kexec.
   - Fixed the warning reported by kernel test bot for ARM64 arch_ima_add_kexec_buffer() - moved this function to a new file namely arch/arm64/kernel/ima_kexec.c

v4:
   - Submitting the patch series on behalf of the original author Prakhar Srivastava <[email protected]>
   - Moved FDT_PROP_IMA_KEXEC_BUFFER ("linux,ima-kexec-buffer") to libfdt.h so that it can be shared by multiple platforms.

v3:
Breakup patches further into separate patches.
   - Refactoring non architecture specific code out of powerpc
   - Update powerpc related code to use fdt functions
   - Update IMA buffer read related code to use of functions
   - Add support to store the memory information of the IMA measurement logs to be carried forward.
   - Update the property strings to align with documented nodes
     https://github.com/devicetree-org/dt-schema/pull/46

v2:
   Break patches into separate patches.
   - Powerpc related Refactoring
   - Updating the docuemntation for chosen node
   - Updating arm64 to support IMA buffer pass

v1:
   Refactoring carrying over IMA measuremnet logs over Kexec. This patch moves the non-architecture specific code out of powerpc and adds to security/ima.(Suggested by Thiago)
   Add Documentation regarding the ima-kexec-buffer node in the chosen node documentation

v0:
   Add a layer of abstraction to use the memory reserved by device tree for ima buffer pass.
   Add support for ima buffer pass using reserved memory for arm64 kexec. Update the arch sepcific code path in kexec file load to store the ima buffer in the reserved memory. The same reserved memory is read on kexec or cold boot.

Lakshmi Ramasubramanian (8):
   powerpc: fix compiler warnings and errors
   powerpc: Move delete_fdt_mem_rsv() to drivers/of
   ima: Define get_ima_kexec_buffer() in drivers/of
   powerpc: Use get_ima_kexec_buffer to get ima kexec buffer
   powerpc: Move remove_ima_buffer() to drivers/of
   powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima
   arm64: Store IMA log information in kimage used for kexec
   arm64: Add IMA kexec buffer to DTB

  arch/arm64/Kconfig                     |   1 + arch/arm64/include/asm/ima.h           |  18 +++++ arch/arm64/include/asm/kexec.h         |   3 + arch/arm64/kernel/Makefile             |   1 + arch/arm64/kernel/ima_kexec.c          |  34 ++++++++ arch/arm64/kernel/machine_kexec_file.c |  18 +++++ arch/powerpc/include/asm/ima.h         |  11 +-- arch/powerpc/include/asm/kexec.h       |   1 - arch/powerpc/kexec/Makefile            |   7 +- arch/powerpc/kexec/file_load.c         |  32 -------- arch/powerpc/kexec/ima.c               | 106 ++----------------------- drivers/of/Makefile                    |   9 +++

Quoted 4 lines

Quoted 2 lines

  drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++ drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are enabled on 2 different kernel CONFIGs, keeping them in 2 files enables us to avoid using "#ifdef" in C files.

thanks,
 -lakshmi

Quoted 12 lines

Quoted 12 lines

  include/linux/kexec.h                  |  24 ++++++ security/integrity/ima/ima_kexec.c     |  51 ++++++++++++

  16 files changed, 313 insertions(+), 149 deletions(-)

  create mode 100644 arch/arm64/include/asm/ima.h create mode 100644 arch/arm64/kernel/ima_kexec.c create mode 100644 drivers/of/ima_kexec.c create mode 100644 drivers/of/kexec_fdt.c

Signature · 1 line

2.29.2

Quoted 8 lines · Rob Herring

Quoted 5 lines · Lakshmi Ramasubramanian

  arch/powerpc/include/asm/kexec.h       |   1 -
  arch/powerpc/kexec/Makefile            |   7 +-
  arch/powerpc/kexec/file_load.c         |  32 --------
  arch/powerpc/kexec/ima.c               | 106 ++-----------------------
  drivers/of/Makefile                    |   9 +++

Quoted 4 lines

Quoted 2 lines

  drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
  drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are enabled on 2 different kernel CONFIGs, keeping them in 2 files enables us to avoid using "#ifdef" in C files.

Quoted 14 lines · Lakshmi Ramasubramanian

Quoted 12 lines · Rob Herring

Quoted 8 lines · Lakshmi Ramasubramanian

   arch/powerpc/include/asm/kexec.h       |   1 -
   arch/powerpc/kexec/Makefile            |   7 +-
   arch/powerpc/kexec/file_load.c         |  32 --------
   arch/powerpc/kexec/ima.c               | 106 ++-----------------------
   drivers/of/Makefile                    |   9 +++

   drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
   drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Quoted 3 lines

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are enabled on 2 different kernel CONFIGs, keeping them in 2 files enables us to avoid using "#ifdef" in C files.

Normally that is true, but just as all of the kexec related functions are co-located in ima/ima_kexec.c, co-locating all of the kexec related functions in drivers/of makes sense.

Quoted 19 lines · Mimi Zohar

Quoted 17 lines · Lakshmi Ramasubramanian

Quoted 8 lines · Rob Herring

Quoted 5 lines · Lakshmi Ramasubramanian

   arch/powerpc/include/asm/kexec.h       |   1 -
   arch/powerpc/kexec/Makefile            |   7 +-
   arch/powerpc/kexec/file_load.c         |  32 --------
   arch/powerpc/kexec/ima.c               | 106 ++-----------------------
   drivers/of/Makefile                    |   9 +++

Quoted 4 lines

Quoted 2 lines

   drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
   drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are enabled on 2 different kernel CONFIGs, keeping them in 2 files enables us to avoid using "#ifdef" in C files.

Quoted 4 lines

Normally that is true, but just as all of the kexec related functions are co-located in ima/ima_kexec.c, co-locating all of the kexec related functions in drivers/of makes sense.

Sounds good - i'll make the change.
Instead of "#ifdef" will use "IS_ENABLED" macro, and define the kexec related functions in drivers/of/ima_kexec.c

Quoted 25 lines · Lakshmi Ramasubramanian

Quoted 23 lines · Mimi Zohar

Quoted 9 lines · Lakshmi Ramasubramanian

Quoted 8 lines · Rob Herring

Quoted 5 lines · Lakshmi Ramasubramanian

    arch/powerpc/include/asm/kexec.h       |   1 -
    arch/powerpc/kexec/Makefile            |   7 +-
    arch/powerpc/kexec/file_load.c         |  32 --------
    arch/powerpc/kexec/ima.c               | 106 ++-----------------------
    drivers/of/Makefile                    |   9 +++

Quoted 8 lines

Quoted 4 lines

Quoted 2 lines

    drivers/of/ima_kexec.c                 |  91 +++++++++++++++++++++
    drivers/of/kexec_fdt.c                 |  55 +++++++++++++

Does this need to be 2 files? Just kexec.c?

Since the functions defined in "ima_kexec.c" and "kexec_fdt.c" are enabled on 2 different kernel CONFIGs, keeping them in 2 files enables us to avoid using "#ifdef" in C files.

Normally that is true, but just as all of the kexec related functions are co-located in ima/ima_kexec.c, co-locating all of the kexec related functions in drivers/of makes sense.

Quoted 3 lines

Sounds good - i'll make the change.
Instead of "#ifdef" will use "IS_ENABLED" macro, and define the kexec related functions in drivers/of/ima_kexec.c

Perhaps name the file kexec.c, as Rob suggested.