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Carry forward IMA measurement log on kexec on ARM64

PATCH Superseded Lakshmi Ramasubramanian 2 participants 11 messages Dec 14, 2020 – Dec 16, 2020

Subsystems (7)

v11 of 19 Superseded Latest is v19 →

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#0 lore raw

v11 cover Carry forward IMA measurement log on kexec on ARM64

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 "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 a29a64445089 ("powerpc: Use common of_kexec_setup_new_fdt()") in https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git "dt/kexec" branch.

Changelog:

v11
- Rebased the changes on the kexec code refactoring done by Rob Herring in his "dt/kexec" branch
- Removed "extern" keyword in function declarations
- Removed unnecessary header files included in C files
- Updated patch descriptions per Thiago's comments

v10
- Moved delete_fdt_mem_rsv(), remove_ima_buffer(), get_ima_kexec_buffer, and get_root_addr_size_cells() to drivers/of/kexec.c
- Moved arch_ima_add_kexec_buffer() to security/integrity/ima/ima_kexec.c
- Conditionally define IMA buffer fields in struct kimage_arch

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 ima buffer functions to drivers/of/kexec.c
powerpc: Use ima kexec node functions
powerpc: Move remove_ima_buffer() to drivers/of/kexec.c
powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to
ima
powerpc: Move arch_ima_add_kexec_buffer to ima
arm64: Free DTB buffer if fdt_open_into() fails
arm64: Add IMA log information in kimage used for kexec

 arch/arm64/Kconfig                     |   1 +
 arch/arm64/include/asm/ima.h           |  24 +++++
 arch/arm64/include/asm/kexec.h         |   5 +
 arch/arm64/kernel/Makefile             |   1 +
 arch/arm64/kernel/ima.c                |  49 +++++++++
 arch/arm64/kernel/machine_kexec_file.c |  12 ++-
 arch/powerpc/include/asm/ima.h         |  14 +--
 arch/powerpc/include/asm/kexec.h       |   1 -
 arch/powerpc/kexec/Makefile            |   7 +-
 arch/powerpc/kexec/file_load.c         |  32 ------
 arch/powerpc/kexec/ima.c               | 138 +------------------------
 drivers/of/kexec.c                     |  94 +++++++++++++++++
 include/linux/of.h                     |   5 +-
 security/integrity/ima/ima.h           |   4 -
 security/integrity/ima/ima_kexec.c     |  73 +++++++++++++
 15 files changed, 266 insertions(+), 194 deletions(-)
 create mode 100644 arch/arm64/include/asm/ima.h
 create mode 100644 arch/arm64/kernel/ima.c
Signature · 1 line
2.29.2
#1 lore raw

PATCH v11 1/8 powerpc: Fix compiler warnings and errors

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().

---
 arch/powerpc/kexec/ima.c | 8 ++++++++
 1 file changed, 8 insertions(+)
arch/powerpc/kexec/ima.c +8 -0
index 720e50e490b6..a36c39db4b1a 100644
@@ -11,6 +11,7 @@
 #include <linux/of.h>
 #include <linux/memblock.h>
 #include <linux/libfdt.h>
+#include <asm/ima.h>
 
 static int get_addr_size_cells(int *addr_cells, int *size_cells)
 {
@@ -103,6 +104,9 @@ int ima_free_kexec_buffer(void)
 /**
  * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
  *
+ * @fdt: Flattened Device Tree to update
+ * @chosen_node: Offset to the chosen node in the device tree
+ *
  * The IMA measurement buffer is of no use to a subsequent kernel, so we always
  * remove it from the device tree.
  */
@@ -131,6 +135,10 @@ void remove_ima_buffer(void *fdt, int chosen_node)
 /**
  * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
  *
+ * @image: kimage struct to set IMA buffer data
+ * @load_addr: Starting address where IMA buffer is loaded at
+ * @size: Number of bytes in the IMA buffer
+ *
  * Architectures should use this function to pass on the IMA buffer
  * information to the next kernel.
  *
Signature · 7 lines
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#2 lore raw

PATCH v11 2/8 powerpc: Move ima buffer functions to drivers/of/kexec.c

In reply to Lakshmi Ramasubramanian

The functions do_get_kexec_buffer() and get_addr_size_cells(), defined in arch/powerpc/kexec/ima.c, retrieve the address and size of the given property from the device tree blob. These functions do not have architecture specific code, but are currently limited to powerpc. do_get_kexec_buffer() 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.

Move architecture independent functions get_ima_kexec_buffer() and get_root_addr_size_cells() to "drivers/of/kexec.c". These functions retrieve the chosen node "linux,ima-kexec-buffer" from the device tree, and return the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call.

---
 drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  3 ++
 2 files changed, 71 insertions(+)
drivers/of/kexec.c +68 -0
index 66787be081fe..9af5371340b1 100644
@@ -30,6 +30,10 @@
 /**
  * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
  *
+ * @fdt: Flattened Device Tree to update
+ * @start: Starting address of the reservation to delete
+ * @size: Size of the reservation to delete
+ *
  * Return: 0 on success, or negative errno on error.
  */
 static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
@@ -226,3 +230,67 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 
 	return 0;
 }
+
+/**
+ * get_root_addr_size_cells - Get address and size of root node
+ *
+ * @addr_cells: Return address of the root node
+ * @size_cells: Return size of the root node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_root_addr_size_cells(int *addr_cells, int *size_cells)
+{
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	*addr_cells = of_n_addr_cells(root);
+	*size_cells = of_n_size_cells(root);
+
+	of_node_put(root);
+
+	return 0;
+}
+
+/**
+ * get_ima_kexec_buffer - Get address and size of IMA kexec buffer
+ *
+ * @fdt: Flattened Device Tree
+ * @chosen_node: Offset of chosen node in the FDT
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size)
+{
+	const void *prop;
+	int addr_cells, size_cells, prop_len;
+	int rc;
+
+	rc = get_root_addr_size_cells(&addr_cells, &size_cells);
+	if (rc)
+		return rc;
+
+	if (fdt)
+		prop = fdt_getprop(fdt, chosen_node,
+				   "linux,ima-kexec-buffer", &prop_len);
+	else
+		prop = of_get_property(of_chosen,
+				       "linux,ima-kexec-buffer", &prop_len);
+
+	if (!prop)
+		return -ENOENT;
+
+	if (prop_len < 4 * (addr_cells + size_cells))
+		return -EINVAL;
+
+	*addr = of_read_number(prop, addr_cells);
+	*size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+	return 0;
+}
include/linux/of.h +3 -0
index 3375f5295875..fb2ef274135d 100644
@@ -562,6 +562,9 @@ struct kimage;
 int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 			   unsigned long initrd_load_addr, unsigned long initrd_len,
 			   const char *cmdline);
+int get_root_addr_size_cells(int *addr_cells, int *size_cells);
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size);
 
 #else /* CONFIG_OF */
 
Signature · 7 lines
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#3 lore raw

Re: [PATCH v11 2/8] powerpc: Move ima buffer functions to drivers/of/kexec.c

Quoted 27 lines · Lakshmi Ramasubramanian

The functions do_get_kexec_buffer() and get_addr_size_cells(), defined in arch/powerpc/kexec/ima.c, retrieve the address and size of the given property from the device tree blob. These functions do not have architecture specific code, but are currently limited to powerpc. do_get_kexec_buffer() 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.

Move architecture independent functions get_ima_kexec_buffer() and get_root_addr_size_cells() to "drivers/of/kexec.c". These functions retrieve the chosen node "linux,ima-kexec-buffer" from the device tree, and return the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call.

---
 drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  3 ++
 2 files changed, 71 insertions(+)
drivers/of/kexec.c +0 -0
index 66787be081fe..9af5371340b1 100644

drivers/of/kexec.c line 36

Quoted 7 lines
drivers/of/kexec.c +4 -0
@@ -30,6 +30,10 @@
 /**
  * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
  *
+ * @fdt: Flattened Device Tree to update
+ * @start: Starting address of the reservation to delete
+ * @size: Size of the reservation to delete
+ *

This belongs in the patch adding fdt_find_and_del_mem_rsv.

Quoted 49 lines
drivers/of/kexec.c +42 -0
  * Return: 0 on success, or negative errno on error.
  */
 static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
@@ -226,3 +230,67 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 
 	return 0;
 }
+
+/**
+ * get_root_addr_size_cells - Get address and size of root node
+ *
+ * @addr_cells: Return address of the root node
+ * @size_cells: Return size of the root node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_root_addr_size_cells(int *addr_cells, int *size_cells)
+{
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	*addr_cells = of_n_addr_cells(root);
+	*size_cells = of_n_size_cells(root);
+
+	of_node_put(root);
+
+	return 0;
+}
+
+/**
+ * get_ima_kexec_buffer - Get address and size of IMA kexec buffer
+ *
+ * @fdt: Flattened Device Tree
+ * @chosen_node: Offset of chosen node in the FDT
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size)
+{
+	const void *prop;
+	int addr_cells, size_cells, prop_len;
+	int rc;
+

drivers/of/kexec.c int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt, · line 284

Quoted 10 lines
drivers/of/kexec.c +10 -0
+	rc = get_root_addr_size_cells(&addr_cells, &size_cells);
+	if (rc)
+		return rc;
+
+	if (fdt)
+		prop = fdt_getprop(fdt, chosen_node,
+				   "linux,ima-kexec-buffer", &prop_len);
+	else
+		prop = of_get_property(of_chosen,
+				       "linux,ima-kexec-buffer", &prop_len);

This is an odd structure. The DT APIs are generally of_foo() for unflattened tree and of_flat_foo() for FDT.

Quoted 17 lines
drivers/of/kexec.c +12 -0
+
+	if (!prop)
+		return -ENOENT;
+
+	if (prop_len < 4 * (addr_cells + size_cells))
+		return -EINVAL;
+
+	*addr = of_read_number(prop, addr_cells);
+	*size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+	return 0;
+}
include/linux/of.h +0 -0
index 3375f5295875..fb2ef274135d 100644

include/linux/of.h struct kimage; · line 567

Quoted 6 lines
include/linux/of.h +3 -0
@@ -562,6 +562,9 @@ struct kimage;
 int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 			   unsigned long initrd_load_addr, unsigned long initrd_len,
 			   const char *cmdline);
+int get_root_addr_size_cells(int *addr_cells, int *size_cells);
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size);

The whole point of moving code out of arch code was to avoid all these cross tree calls.

I was expecting the next step to be moving setup_ima_buffer() call into of_kexec_setup_new_fdt with all the code in powerpc/kexec/ima.c moved here. Then the end result to enable on arm64 is just selecting HAVE_IMA_KEXEC and adding fields to kimage_arch.

Rob

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#4 lore raw

Re: [PATCH v11 2/8] powerpc: Move ima buffer functions to drivers/of/kexec.c

Quoted 23 lines · Rob Herring
Quoted 22 lines · Lakshmi Ramasubramanian

The functions do_get_kexec_buffer() and get_addr_size_cells(), defined in arch/powerpc/kexec/ima.c, retrieve the address and size of the given property from the device tree blob. These functions do not have architecture specific code, but are currently limited to powerpc. do_get_kexec_buffer() 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.

Move architecture independent functions get_ima_kexec_buffer() and get_root_addr_size_cells() to "drivers/of/kexec.c". These functions retrieve the chosen node "linux,ima-kexec-buffer" from the device tree, and return the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call.

---
  drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
  include/linux/of.h |  3 ++
  2 files changed, 71 insertions(+)
Quoted 14 lines

drivers/of/kexec.c line 36

Quoted 12 lines
drivers/of/kexec.c +4 -0
index 66787be081fe..9af5371340b1 100644
@@ -30,6 +30,10 @@
  /**
   * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
   *
+ * @fdt: Flattened Device Tree to update
+ * @start: Starting address of the reservation to delete
+ * @size: Size of the reservation to delete
+ *

This belongs in the patch adding fdt_find_and_del_mem_rsv.

Yes.

Quoted 55 lines
Quoted 55 lines
drivers/of/kexec.c +47 -0
   * Return: 0 on success, or negative errno on error.
   */
  static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
@@ -226,3 +230,67 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 
  	return 0;
  }
+
+/**
+ * get_root_addr_size_cells - Get address and size of root node
+ *
+ * @addr_cells: Return address of the root node
+ * @size_cells: Return size of the root node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_root_addr_size_cells(int *addr_cells, int *size_cells)
+{
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	*addr_cells = of_n_addr_cells(root);
+	*size_cells = of_n_size_cells(root);
+
+	of_node_put(root);
+
+	return 0;
+}
+
+/**
+ * get_ima_kexec_buffer - Get address and size of IMA kexec buffer
+ *
+ * @fdt: Flattened Device Tree
+ * @chosen_node: Offset of chosen node in the FDT
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size)
+{
+	const void *prop;
+	int addr_cells, size_cells, prop_len;
+	int rc;
+
+	rc = get_root_addr_size_cells(&addr_cells, &size_cells);
+	if (rc)
+		return rc;
+
+	if (fdt)
Quoted 9 lines

drivers/of/kexec.c int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt, · line 284

Quoted 5 lines
drivers/of/kexec.c +5 -0
+		prop = fdt_getprop(fdt, chosen_node,
+				   "linux,ima-kexec-buffer", &prop_len);
+	else
+		prop = of_get_property(of_chosen,
+				       "linux,ima-kexec-buffer", &prop_len);

This is an odd structure. The DT APIs are generally of_foo() for unflattened tree and of_flat_foo() for FDT.

Ok - will update.

Quoted 27 lines
Quoted 17 lines
drivers/of/kexec.c +12 -0
+
+	if (!prop)
+		return -ENOENT;
+
+	if (prop_len < 4 * (addr_cells + size_cells))
+		return -EINVAL;
+
+	*addr = of_read_number(prop, addr_cells);
+	*size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+	return 0;
+}
include/linux/of.h +0 -0
index 3375f5295875..fb2ef274135d 100644

include/linux/of.h struct kimage; · line 567

Quoted 6 lines
include/linux/of.h +3 -0
@@ -562,6 +562,9 @@ struct kimage;
  int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
  			   unsigned long initrd_load_addr, unsigned long initrd_len,
  			   const char *cmdline);
+int get_root_addr_size_cells(int *addr_cells, int *size_cells);
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size);

The whole point of moving code out of arch code was to avoid all these cross tree calls.

Quoted 5 lines

I was expecting the next step to be moving setup_ima_buffer() call into of_kexec_setup_new_fdt with all the code in powerpc/kexec/ima.c moved here. Then the end result to enable on arm64 is just selecting HAVE_IMA_KEXEC and adding fields to kimage_arch.

setup_ima_buffer() implemented for powerpc can be simplified by using
fdt_appendprop_addrrange() to add the IMA buffer's address and size to "linux,ima-kexec-buffer" node. With that change, setup_ima_buffer() can be moved into of_kexec_setup_new_fdt along with all the code in powerpc/kexec/ima.c to drivers'of/kexec.c

I'll make the above change and post the next version shortly.

thanks,
-lakshmi

#5 lore raw

PATCH v11 3/8 powerpc: Use ima kexec node functions

In reply to Lakshmi Ramasubramanian

do_get_kexec_buffer() and get_addr_size_cells() are called by ima_get_kexec_buffer(), ima_free_kexec_buffer, and remove_ima_buffer() to retrieve the address and size of the buffer used for carrying forward the IMA measurement log across kexec system call. These functions correctly handle a device tree property that is a child node of the root node, but not anything other than the immediate root child nodes.

Use the architecture independent functions get_ima_kexec_buffer() and get_root_addr_size_cells() defined in "drivers/of/kexec.c", to get the address and size of the IMA measurement log buffer from the device tree. Remove do_get_kexec_buffer() and get_addr_size_cells() since they are not used anymore.

---
 arch/powerpc/kexec/ima.c | 58 +++++-----------------------------------
 1 file changed, 7 insertions(+), 51 deletions(-)
arch/powerpc/kexec/ima.c +7 -51
index a36c39db4b1a..906e8212435d 100644
@@ -13,40 +13,6 @@
 #include <linux/libfdt.h>
 #include <asm/ima.h>
 
-static int get_addr_size_cells(int *addr_cells, int *size_cells)
-{
-	struct device_node *root;
-
-	root = of_find_node_by_path("/");
-	if (!root)
-		return -EINVAL;
-
-	*addr_cells = of_n_addr_cells(root);
-	*size_cells = of_n_size_cells(root);
-
-	of_node_put(root);
-
-	return 0;
-}
-
-static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
-			       size_t *size)
-{
-	int ret, addr_cells, size_cells;
-
-	ret = get_addr_size_cells(&addr_cells, &size_cells);
-	if (ret)
-		return ret;
-
-	if (len < 4 * (addr_cells + size_cells))
-		return -ENOENT;
-
-	*addr = of_read_number(prop, addr_cells);
-	*size = of_read_number(prop + 4 * addr_cells, size_cells);
-
-	return 0;
-}
-
 /**
  * ima_get_kexec_buffer - get IMA buffer from the previous kernel
  * @addr:	On successful return, set to point to the buffer contents.
@@ -56,16 +22,11 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
  */
 int ima_get_kexec_buffer(void **addr, size_t *size)
 {
-	int ret, len;
+	int ret;
 	unsigned long tmp_addr;
 	size_t tmp_size;
-	const void *prop;
 
-	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
-	if (!prop)
-		return -ENOENT;
-
-	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+	ret = get_ima_kexec_buffer(NULL, 0, &tmp_addr, &tmp_size);
 	if (ret)
 		return ret;
 
@@ -89,7 +50,7 @@ int ima_free_kexec_buffer(void)
 	if (!prop)
 		return -ENOENT;
 
-	ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+	ret = get_ima_kexec_buffer(NULL, 0, &addr, &size);
 	if (ret)
 		return ret;
 
@@ -98,7 +59,6 @@ int ima_free_kexec_buffer(void)
 		return ret;
 
 	return memblock_free(addr, size);
-
 }
 
 /**
@@ -112,19 +72,15 @@ int ima_free_kexec_buffer(void)
  */
 void remove_ima_buffer(void *fdt, int chosen_node)
 {
-	int ret, len;
+	int ret;
 	unsigned long addr;
 	size_t size;
-	const void *prop;
 
-	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
-	if (!prop)
+	ret = get_ima_kexec_buffer(fdt, chosen_node, &addr, &size);
+	if (ret)
 		return;
 
-	ret = do_get_kexec_buffer(prop, len, &addr, &size);
 	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
-	if (ret)
-		return;
 
 	ret = delete_fdt_mem_rsv(fdt, addr, size);
 	if (!ret)
@@ -191,7 +147,7 @@ int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
 	if (!image->arch.ima_buffer_size)
 		return 0;
 
-	ret = get_addr_size_cells(&addr_cells, &size_cells);
+	ret = get_root_addr_size_cells(&addr_cells, &size_cells);
 	if (ret)
 		return ret;
 
Signature · 1 line
2.29.2
#6 lore raw

PATCH v11 4/8 powerpc: Move remove_ima_buffer() to drivers/of/kexec.c

In reply to Lakshmi Ramasubramanian

remove_ima_buffer() removes the chosen node "linux,ima-kexec-buffer" from the device tree and frees the memory reserved for carrying forward the IMA measurement logs on kexec. This function does not have architecture specific code, but is currently limited to powerpc.

When CONFIG_IMA isn't set, remove_ima_buffer() is a NOP. Therefore, kexec_file_load() will not remove the IMA kexec buffer when creating the FDT for the next kernel.

Define remove_ima_buffer() when CONFIG_KEXEC_FILE is enabled. kexec_file_load() will then remove the IMA kexec buffer when creating the FDT for the next kernel.

Move remove_ima_buffer() to "drivers/of/kexec.c" so that it is accessible for other architectures as well.

With this change the function delete_fdt_mem_rsv() defined in arch/powerpc/kexec/file_load.c is no longer used. Remove delete_fdt_mem_rsv().

---
 arch/powerpc/include/asm/ima.h   |  8 +-------
 arch/powerpc/include/asm/kexec.h |  1 -
 arch/powerpc/kexec/file_load.c   | 32 --------------------------------
 arch/powerpc/kexec/ima.c         | 26 --------------------------
 drivers/of/kexec.c               | 26 ++++++++++++++++++++++++++
 include/linux/of.h               |  2 +-
 6 files changed, 28 insertions(+), 67 deletions(-)
arch/powerpc/include/asm/ima.h +1 -7
index ead488cf3981..fbc0c866b6bc 100644
@@ -2,17 +2,11 @@
 #ifndef _ASM_POWERPC_IMA_H
 #define _ASM_POWERPC_IMA_H
 
-struct kimage;
+#include <linux/of.h>
 
 int ima_get_kexec_buffer(void **addr, size_t *size);
 int ima_free_kexec_buffer(void);
 
-#ifdef CONFIG_IMA
-void remove_ima_buffer(void *fdt, int chosen_node);
-#else
-static inline void remove_ima_buffer(void *fdt, int chosen_node) {}
-#endif
-
 #ifdef CONFIG_IMA_KEXEC
 int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
 			      size_t size);
arch/powerpc/include/asm/kexec.h +0 -1
index dbf09d2f36d0..d4b7d2d6191d 100644
@@ -126,7 +126,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
 int setup_new_fdt(const struct kimage *image, void *fdt,
 		  unsigned long initrd_load_addr, unsigned long initrd_len,
 		  const char *cmdline);
-int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
 
 #ifdef CONFIG_PPC64
 struct kexec_buf;
arch/powerpc/kexec/file_load.c +0 -32
index 956bcb2d1ec2..a116f1eb35b5 100644
@@ -110,38 +110,6 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
 	return 0;
 }
 
-/**
- * delete_fdt_mem_rsv - delete memory reservation with given address and size
- *
- * Return: 0 on success, or negative errno on error.
- */
-int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
-{
-	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
-
-	for (i = 0; i < num_rsvs; i++) {
-		uint64_t rsv_start, rsv_size;
-
-		ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
-		if (ret) {
-			pr_err("Malformed device tree.\n");
-			return -EINVAL;
-		}
-
-		if (rsv_start == start && rsv_size == size) {
-			ret = fdt_del_mem_rsv(fdt, i);
-			if (ret) {
-				pr_err("Error deleting device tree reservation.\n");
-				return -EINVAL;
-			}
-
-			return 0;
-		}
-	}
-
-	return -ENOENT;
-}
-
 /*
  * setup_new_fdt - modify /chosen and memory reservation for the next kernel
  * @image:		kexec image being loaded.
arch/powerpc/kexec/ima.c +0 -26
index 906e8212435d..68017123b07d 100644
@@ -61,32 +61,6 @@ int ima_free_kexec_buffer(void)
 	return memblock_free(addr, size);
 }
 
-/**
- * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
- *
- * @fdt: Flattened Device Tree to update
- * @chosen_node: Offset to the chosen node in the device tree
- *
- * The IMA measurement buffer is of no use to a subsequent kernel, so we always
- * remove it from the device tree.
- */
-void remove_ima_buffer(void *fdt, int chosen_node)
-{
-	int ret;
-	unsigned long addr;
-	size_t size;
-
-	ret = get_ima_kexec_buffer(fdt, chosen_node, &addr, &size);
-	if (ret)
-		return;
-
-	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
-
-	ret = delete_fdt_mem_rsv(fdt, addr, size);
-	if (!ret)
-		pr_debug("Removed old IMA buffer reservation.\n");
-}
-
 #ifdef CONFIG_IMA_KEXEC
 /**
  * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
drivers/of/kexec.c +26 -0
index 9af5371340b1..5939483d3114 100644
@@ -294,3 +294,29 @@ int get_ima_kexec_buffer(void *fdt, int chosen_node,
 
 	return 0;
 }
+
+/**
+ * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
+ *
+ * @fdt: Flattened Device Tree to update
+ * @chosen_node: Offset to the chosen node in the device tree
+ *
+ * The IMA measurement buffer is of no use to a subsequent kernel, so we always
+ * remove it from the device tree.
+ */
+void remove_ima_buffer(void *fdt, int chosen_node)
+{
+	int ret;
+	unsigned long addr;
+	size_t size;
+
+	ret = get_ima_kexec_buffer(fdt, chosen_node, &addr, &size);
+	if (ret)
+		return;
+
+	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+
+	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
+	if (!ret)
+		pr_debug("Removed old IMA buffer reservation.\n");
+}
include/linux/of.h +1 -1
index fb2ef274135d..67c1298746dd 100644
@@ -565,7 +565,7 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 int get_root_addr_size_cells(int *addr_cells, int *size_cells);
 int get_ima_kexec_buffer(void *fdt, int chosen_node,
 			 unsigned long *addr, size_t *size);
-
+void remove_ima_buffer(void *fdt, int chosen_node);
 #else /* CONFIG_OF */
 
 static inline void of_core_init(void)
Signature · 7 lines
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#7 lore raw

PATCH v11 5/8 powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima

In reply to 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 "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.

---
 arch/powerpc/include/asm/ima.h     |  3 --
 arch/powerpc/kexec/Makefile        |  7 +---
 arch/powerpc/kexec/ima.c           | 51 -----------------------------
 security/integrity/ima/ima_kexec.c | 52 ++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 60 deletions(-)
arch/powerpc/include/asm/ima.h +0 -3
index fbc0c866b6bc..3875c9334d64 100644
@@ -4,9 +4,6 @@
 
 #include <linux/of.h>
 
-int ima_get_kexec_buffer(void **addr, size_t *size);
-int ima_free_kexec_buffer(void);
-
 #ifdef CONFIG_IMA_KEXEC
 int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
 			      size_t size);
arch/powerpc/kexec/Makefile +1 -6
index 4aff6846c772..f54a9dbff4c8 100644
@@ -9,12 +9,7 @@ obj-$(CONFIG_PPC32)		+= relocate_32.o
 
 obj-$(CONFIG_KEXEC_FILE)	+= file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o
 
-ifdef CONFIG_HAVE_IMA_KEXEC
-ifdef CONFIG_IMA
-obj-y				+= ima.o
-endif
-endif
-
+obj-$(CONFIG_IMA_KEXEC)		+= ima.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_core_$(BITS).o := n
arch/powerpc/kexec/ima.c +0 -51

63 lines not on this page · raw message

security/integrity/ima/ima_kexec.c +52 -0

65 lines not on this page · raw message

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#8 lore raw

PATCH v11 6/8 powerpc: Move arch_ima_add_kexec_buffer to ima

In reply to Lakshmi Ramasubramanian

arch_ima_add_kexec_buffer() sets the address and size of the IMA measurement log in the architecture specific field in struct kimage. This function does not have architecture specific code, but is currently limited to powerpc.

Move arch_ima_add_kexec_buffer() to security/integrity/ima/ima_kexec.c so that it is accessible for other architectures as well.

---
 arch/powerpc/include/asm/ima.h     |  3 ---
 arch/powerpc/kexec/ima.c           | 21 ---------------------
 security/integrity/ima/ima.h       |  4 ----
 security/integrity/ima/ima_kexec.c | 21 +++++++++++++++++++++
 4 files changed, 21 insertions(+), 28 deletions(-)
arch/powerpc/include/asm/ima.h +0 -3
index 3875c9334d64..cb088e442d11 100644
@@ -5,9 +5,6 @@
 #include <linux/of.h>
 
 #ifdef CONFIG_IMA_KEXEC
-int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
-			      size_t size);
-
 int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node);
 #else
 static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
arch/powerpc/kexec/ima.c +0 -21
index 82730c13a4df..d66ae17c64af 100644
@@ -12,27 +12,6 @@
 #include <linux/libfdt.h>
 #include <asm/ima.h>
 
-/**
- * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
- *
- * @image: kimage struct to set IMA buffer data
- * @load_addr: Starting address where IMA buffer is loaded at
- * @size: Number of bytes in 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)
-{
-	image->arch.ima_buffer_addr = load_addr;
-	image->arch.ima_buffer_size = size;
-
-	return 0;
-}
-
 static int write_number(void *p, u64 value, int cells)
 {
 	if (cells == 1) {
security/integrity/ima/ima.h +0 -4
index 6ebefec616e4..7c3947ad3773 100644
@@ -24,10 +24,6 @@
 
 #include "../integrity.h"
 
-#ifdef CONFIG_HAVE_IMA_KEXEC
-#include <asm/ima.h>
-#endif
-
 enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_BINARY_NO_FIELD_LEN,
 		     IMA_SHOW_BINARY_OLD_STRING_FMT, IMA_SHOW_ASCII };
 enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8, TPM_PCR10 = 10 };
security/integrity/ima/ima_kexec.c +21 -0
index 9527118939b8..7293eb4545ac 100644
@@ -75,6 +75,27 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
 	return ret;
 }
 
+/**
+ * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
+ *
+ * @image: kimage struct to set IMA buffer data
+ * @load_addr: Starting address where IMA buffer is loaded at
+ * @size: Number of bytes in 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.
+ */
+static int arch_ima_add_kexec_buffer(struct kimage *image,
+				     unsigned long load_addr, size_t size)
+{
+	image->arch.ima_buffer_addr = load_addr;
+	image->arch.ima_buffer_size = size;
+
+	return 0;
+}
+
 /*
  * Called during kexec_file_load so that IMA can add a segment to the kexec
  * image for the measurement list for the next kernel.
Signature · 1 line
2.29.2
#9 lore raw

PATCH v11 7/8 arm64: Free DTB buffer if fdt_open_into() fails

In reply to Lakshmi Ramasubramanian

create_dtb() function allocates memory for the device tree blob (DTB) and calls fdt_open_into(). If this call fails the memory allocated for the DTB is not freed before returning from create_dtb() thereby leaking memory.

Call vfree() to free the memory allocated for the DTB if fdt_open_into() fails.

---
 arch/arm64/kernel/machine_kexec_file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
arch/arm64/kernel/machine_kexec_file.c +3 -1
index 7de9c47dee7c..3e045cd62451 100644
@@ -65,8 +65,10 @@ static int create_dtb(struct kimage *image,
 
 		/* duplicate a device tree blob */
 		ret = fdt_open_into(initial_boot_params, buf, buf_size);
-		if (ret)
+		if (ret) {
+			vfree(buf);
 			return -EINVAL;
+		}
 
 		ret = of_kexec_setup_new_fdt(image, buf, initrd_load_addr,
 					     initrd_len, cmdline);
Signature · 1 line
2.29.2
#10 lore raw

PATCH v11 8/8 arm64: Add IMA log information in kimage used for kexec

In reply to 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.

Any existing "linux,ima-kexec-buffer" property in the device tree needs to be removed and its corresponding memory reservation in the currently running kernel needs to be freed. The address and size of the current kernel's IMA measurement log need to be added to the device tree's IMA kexec buffer node and memory for the buffer needs to be reserved for the log to be carried over to the next kernel on the kexec call.

Add address and size fields to "struct kimage_arch" for ARM64 platform to hold the address and size of the IMA measurement log buffer. Remove any existing "linux,ima-kexec-buffer" property in the device tree and free the corresponding memory reservation in the currently running kernel. Add "linux,ima-kexec-buffer" property to the device tree and reserve the memory for storing the IMA log that needs to be passed from the current kernel to the next one.

Update CONFIG_KEXEC_FILE to select CONFIG_HAVE_IMA_KEXEC to indicate that the IMA measurement log information is present in the device tree for ARM64.

---
 arch/arm64/Kconfig                     |  1 +
 arch/arm64/include/asm/ima.h           | 24 +++++++++++++
 arch/arm64/include/asm/kexec.h         |  5 +++
 arch/arm64/kernel/Makefile             |  1 +
 arch/arm64/kernel/ima.c                | 49 ++++++++++++++++++++++++++
 arch/arm64/kernel/machine_kexec_file.c |  8 +++++
 6 files changed, 88 insertions(+)
 create mode 100644 arch/arm64/include/asm/ima.h
 create mode 100644 arch/arm64/kernel/ima.c
arch/arm64/Kconfig +1 -0
index 1d466addb078..c85d18b1f2fd 100644
@@ -1094,6 +1094,7 @@ config KEXEC
 config KEXEC_FILE
 	bool "kexec file based system call"
 	select KEXEC_CORE
+	select HAVE_IMA_KEXEC
 	help
 	  This is new version of kexec system call. This system call is
 	  file based and takes file descriptors as system call argument
arch/arm64/include/asm/ima.h new file +24 -0
new file mode 100644
index 000000000000..8b105157e55f
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020 Microsoft Corporation
+ *
+ * Author: Lakshmi Ramasubramanian <[email protected]>
+ *
+ */
+#ifndef _ASM_ARCH_IMA_H
+#define _ASM_ARCH_IMA_H
+
+#include <linux/of.h>
+
+#ifdef CONFIG_IMA_KEXEC
+int setup_ima_buffer(const struct kimage *image, void *dtb, int off);
+#else
+static inline int setup_ima_buffer(const struct kimage *image, void *dtb,
+				   int off)
+{
+	remove_ima_buffer(dtb, off);
+	return 0;
+}
+#endif /* CONFIG_IMA_KEXEC */
+
+#endif /* _ASM_ARCH_IMA_H */
arch/arm64/include/asm/kexec.h +5 -0
index d24b527e8c00..2bd19ccb6c43 100644
@@ -100,6 +100,11 @@ struct kimage_arch {
 	void *elf_headers;
 	unsigned long elf_headers_mem;
 	unsigned long elf_headers_sz;
+
+#ifdef CONFIG_IMA_KEXEC
+	phys_addr_t ima_buffer_addr;
+	size_t ima_buffer_size;
+#endif
 };
 
 extern const struct kexec_file_ops kexec_image_ops;
arch/arm64/kernel/Makefile +1 -0
index bbaf0bc4ad60..da83f1b3367e 100644
@@ -60,6 +60,7 @@ obj-$(CONFIG_ARM_SDE_INTERFACE)		+= sdei.o
 obj-$(CONFIG_ARM64_PTR_AUTH)		+= pointer_auth.o
 obj-$(CONFIG_SHADOW_CALL_STACK)		+= scs.o
 obj-$(CONFIG_ARM64_MTE)			+= mte.o
+obj-$(CONFIG_IMA_KEXEC)			+= ima.o
 
 obj-y					+= vdso/ probes/
 obj-$(CONFIG_COMPAT_VDSO)		+= vdso32/
arch/arm64/kernel/ima.c new file +49 -0

49 lines not on this page · raw message

arch/arm64/kernel/machine_kexec_file.c +8 -0
index 3e045cd62451..37a528aca780 100644
@@ -21,6 +21,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
+#include <asm/ima.h>
 
 const struct kexec_file_ops * const kexec_file_loaders[] = {
 	&kexec_image_ops,
@@ -83,6 +84,13 @@ static int create_dtb(struct kimage *image,
 			}
 		}
 
+		ret = setup_ima_buffer(image, buf,
+				       fdt_path_offset(buf, "/chosen"));
+		if (ret) {
+			vfree(buf);
+			return ret;
+		}
+
 		/* trim it */
 		fdt_pack(buf);
 		*dtb = buf;
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