[PATCH v13 0/6] Carry forward IMA measurement log on kexec on ARM64

[PATCH v13 0/6] Carry forward IMA measurement log on kexec on ARM64

[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
"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:

v13
  - Moved the arch independent functions to drivers/of/kexec.c
    and then refactored the code.
  - Moved arch_ima_add_kexec_buffer() to
    security/integrity/ima/ima_kexec.c

v12
  - Use fdt_appendprop_addrrange() in setup_ima_buffer()
    to setup the IMA measurement list property in
    the device tree.
  - Moved architecture independent functions from
    "arch/powerpc/kexec/ima.c" to "drivers/of/kexec."
  - Deleted "arch/powerpc/kexec/ima.c" and
    "arch/powerpc/include/asm/ima.h".

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 <prsriva@linux.microsoft.com>
  - 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 (6):
  ima: Move arch_ima_add_kexec_buffer() to ima
  powerpc: Move arch independent ima kexec functions to
    drivers/of/kexec.c
  kexec: Use fdt_appendprop_addrrange() to add ima buffer to FDT
  powerpc: Delete unused function delete_fdt_mem_rsv()
  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/kexec.h         |   5 +
 arch/arm64/kernel/machine_kexec_file.c |   4 +-
 arch/powerpc/include/asm/ima.h         |  30 ----
 arch/powerpc/include/asm/kexec.h       |   1 -
 arch/powerpc/kexec/Makefile            |   7 -
 arch/powerpc/kexec/file_load.c         |  39 -----
 arch/powerpc/kexec/ima.c               | 219 -------------------------
 drivers/of/kexec.c                     | 188 +++++++++++++++++++++
 include/linux/of.h                     |   2 +
 security/integrity/ima/ima.h           |   4 -
 security/integrity/ima/ima_kexec.c     |  23 +++
 12 files changed, 222 insertions(+), 301 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/ima.h
 delete mode 100644 arch/powerpc/kexec/ima.c

-- 
2.29.2

[PATCH v13 1/6] ima: Move arch_ima_add_kexec_buffer() to ima

[Lakshmi Ramasubramanian]

arch_ima_add_kexec_buffer() defined in "arch/powerpc/kexec/ima.c"
sets up the address and size of the IMA measurement list in
the architecture specific fields in kimage struct. This function does not
have architecture specific code, but is currently limited to powerpc.

Move arch_ima_add_kexec_buffer() to ima.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/powerpc/include/asm/ima.h     |  3 ---
 arch/powerpc/kexec/ima.c           | 17 -----------------
 security/integrity/ima/ima_kexec.c | 22 ++++++++++++++++++++++
 3 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
index ead488cf3981..51f64fd06c19 100644
--- a/arch/powerpc/include/asm/ima.h
+++ b/arch/powerpc/include/asm/ima.h
@@ -14,9 +14,6 @@ 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);
-
 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,
diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
index 720e50e490b6..7378d59c0c1e 100644
--- a/arch/powerpc/kexec/ima.c
+++ b/arch/powerpc/kexec/ima.c
@@ -128,23 +128,6 @@ void remove_ima_buffer(void *fdt, int chosen_node)
 }
 
 #ifdef CONFIG_IMA_KEXEC
-/**
- * arch_ima_add_kexec_buffer - do arch-specific steps to add 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) {
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 121de3e04af2..38bcd7543e27 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -10,6 +10,7 @@
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 #include <linux/kexec.h>
+#include <linux/ima.h>
 #include "ima.h"
 
 #ifdef CONFIG_IMA_KEXEC
@@ -71,6 +72,27 @@ 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.
-- 
2.29.2

[PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
and freeing the resources required to carry over the IMA measurement
list from the current kernel to the next kernel across kexec system call.
These functions do not have architecture specific code, but are
currently limited to powerpc.

Move setup_ima_buffer() call into of_kexec_setup_new_fdt() defined in
"drivers/of/kexec.c".

Move the remaining architecture independent functions from
"arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c".
Delete "arch/powerpc/kexec/ima.c" and "arch/powerpc/include/asm/ima.h".
Remove references to the deleted files in powerpc and in ima.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/powerpc/include/asm/ima.h     |  27 ----
 arch/powerpc/kexec/Makefile        |   7 -
 arch/powerpc/kexec/file_load.c     |   7 -
 arch/powerpc/kexec/ima.c           | 202 -------------------------
 drivers/of/kexec.c                 | 235 +++++++++++++++++++++++++++++
 include/linux/of.h                 |   2 +
 security/integrity/ima/ima.h       |   4 -
 security/integrity/ima/ima_kexec.c |   1 +
 8 files changed, 238 insertions(+), 247 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/ima.h
 delete mode 100644 arch/powerpc/kexec/ima.c

diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
deleted file mode 100644
index 51f64fd06c19..000000000000
--- a/arch/powerpc/include/asm/ima.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_POWERPC_IMA_H
-#define _ASM_POWERPC_IMA_H
-
-struct kimage;
-
-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 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,
-				   int chosen_node)
-{
-	remove_ima_buffer(fdt, chosen_node);
-	return 0;
-}
-#endif /* CONFIG_IMA_KEXEC */
-
-#endif /* _ASM_POWERPC_IMA_H */
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 4aff6846c772..b6c52608cb49 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -9,13 +9,6 @@ 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
-
-
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_core_$(BITS).o := n
 KCOV_INSTRUMENT_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
index 956bcb2d1ec2..9f3ec0b239ef 100644
--- a/arch/powerpc/kexec/file_load.c
+++ b/arch/powerpc/kexec/file_load.c
@@ -20,7 +20,6 @@
 #include <linux/of_fdt.h>
 #include <linux/libfdt.h>
 #include <asm/setup.h>
-#include <asm/ima.h>
 
 #define SLAVE_CODE_SIZE		256	/* First 0x100 bytes */
 
@@ -163,12 +162,6 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
 	if (ret)
 		goto err;
 
-	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
-	if (ret) {
-		pr_err("Error setting up the new device tree.\n");
-		return ret;
-	}
-
 	return 0;
 
 err:
diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
deleted file mode 100644
index 7378d59c0c1e..000000000000
--- a/arch/powerpc/kexec/ima.c
+++ /dev/null
@@ -1,202 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Copyright (C) 2016 IBM Corporation
- *
- * Authors:
- * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
- */
-
-#include <linux/slab.h>
-#include <linux/kexec.h>
-#include <linux/of.h>
-#include <linux/memblock.h>
-#include <linux/libfdt.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.
- * @size:	On successful return, set to the buffer size.
- *
- * Return: 0 on success, negative errno on error.
- */
-int ima_get_kexec_buffer(void **addr, size_t *size)
-{
-	int ret, len;
-	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);
-	if (ret)
-		return ret;
-
-	*addr = __va(tmp_addr);
-	*size = tmp_size;
-
-	return 0;
-}
-
-/**
- * ima_free_kexec_buffer - free memory used by the IMA buffer
- */
-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 = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
-	if (ret)
-		return ret;
-
-	ret = of_remove_property(of_chosen, prop);
-	if (ret)
-		return ret;
-
-	return memblock_free(addr, size);
-
-}
-
-/**
- * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
- *
- * 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, len;
-	unsigned long addr;
-	size_t size;
-	const void *prop;
-
-	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
-	if (!prop)
-		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)
-		pr_debug("Removed old IMA buffer reservation.\n");
-}
-
-#ifdef CONFIG_IMA_KEXEC
-static int write_number(void *p, u64 value, int cells)
-{
-	if (cells == 1) {
-		u32 tmp;
-
-		if (value > U32_MAX)
-			return -EINVAL;
-
-		tmp = cpu_to_be32(value);
-		memcpy(p, &tmp, sizeof(tmp));
-	} else if (cells == 2) {
-		u64 tmp;
-
-		tmp = cpu_to_be64(value);
-		memcpy(p, &tmp, sizeof(tmp));
-	} else
-		return -EINVAL;
-
-	return 0;
-}
-
-/**
- * setup_ima_buffer - add IMA buffer information to the fdt
- * @image:		kexec image being loaded.
- * @fdt:		Flattened device tree for the next kernel.
- * @chosen_node:	Offset to the chosen node.
- *
- * Return: 0 on success, or negative errno on error.
- */
-int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
-{
-	int ret, addr_cells, size_cells, entry_size;
-	u8 value[16];
-
-	remove_ima_buffer(fdt, chosen_node);
-	if (!image->arch.ima_buffer_size)
-		return 0;
-
-	ret = get_addr_size_cells(&addr_cells, &size_cells);
-	if (ret)
-		return ret;
-
-	entry_size = 4 * (addr_cells + size_cells);
-
-	if (entry_size > sizeof(value))
-		return -EINVAL;
-
-	ret = write_number(value, image->arch.ima_buffer_addr, addr_cells);
-	if (ret)
-		return ret;
-
-	ret = write_number(value + 4 * addr_cells, image->arch.ima_buffer_size,
-			   size_cells);
-	if (ret)
-		return ret;
-
-	ret = fdt_setprop(fdt, chosen_node, "linux,ima-kexec-buffer", value,
-			  entry_size);
-	if (ret < 0)
-		return -EINVAL;
-
-	ret = fdt_add_mem_rsv(fdt, image->arch.ima_buffer_addr,
-			      image->arch.ima_buffer_size);
-	if (ret)
-		return -EINVAL;
-
-	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
-		 image->arch.ima_buffer_addr, image->arch.ima_buffer_size);
-
-	return 0;
-}
-#endif /* CONFIG_IMA_KEXEC */
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 66787be081fe..33d97106f176 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -11,6 +11,7 @@
 
 #include <linux/kernel.h>
 #include <linux/kexec.h>
+#include <linux/memblock.h>
 #include <linux/libfdt.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
@@ -59,6 +60,181 @@ static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned lon
 	return -ENOENT;
 }
 
+/**
+ * get_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.
+ */
+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;
+}
+
+/**
+ * do_get_kexec_buffer - Get address and size of device tree property
+ *
+ * @prop: Device tree property
+ * @len: Size of @prop
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+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;
+}
+
+#ifdef CONFIG_HAVE_IMA_KEXEC
+/**
+ * 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.
+ */
+static void remove_ima_buffer(void *fdt, int chosen_node)
+{
+	int ret, len;
+	unsigned long addr;
+	size_t size;
+	const void *prop;
+
+	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
+	if (!prop)
+		return;
+
+	ret = do_get_kexec_buffer(prop, len, &addr, &size);
+	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+	if (ret)
+		return;
+
+	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
+	if (!ret)
+		pr_debug("Removed old IMA buffer reservation.\n");
+}
+#else /* CONFIG_HAVE_IMA_KEXEC */
+static inline void remove_ima_buffer(void *fdt, int chosen_node) {}
+#endif /* CONFIG_HAVE_IMA_KEXEC */
+
+#ifdef CONFIG_IMA_KEXEC
+/**
+ * write_number - Convert number to big-endian format
+ *
+ * @p:		Buffer to write the number to
+ * @value:	Number to convert
+ * @cells:	Number of cells
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int write_number(void *p, u64 value, int cells)
+{
+	if (cells == 1) {
+		u32 tmp;
+
+		if (value > U32_MAX)
+			return -EINVAL;
+
+		tmp = cpu_to_be32(value);
+		memcpy(p, &tmp, sizeof(tmp));
+	} else if (cells == 2) {
+		u64 tmp;
+
+		tmp = cpu_to_be64(value);
+		memcpy(p, &tmp, sizeof(tmp));
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * setup_ima_buffer - add IMA buffer information to the fdt
+ * @image:		kexec image being loaded.
+ * @fdt:		Flattened device tree for the next kernel.
+ * @chosen_node:	Offset to the chosen node.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int setup_ima_buffer(const struct kimage *image, void *fdt,
+			    int chosen_node)
+{
+	int ret, addr_cells, size_cells, entry_size;
+	u8 value[16];
+
+	if (!image->arch.ima_buffer_size)
+		return 0;
+
+	ret = get_addr_size_cells(&addr_cells, &size_cells);
+	if (ret)
+		return ret;
+
+	entry_size = 4 * (addr_cells + size_cells);
+
+	if (entry_size > sizeof(value))
+		return -EINVAL;
+
+	ret = write_number(value, image->arch.ima_buffer_addr, addr_cells);
+	if (ret)
+		return ret;
+
+	ret = write_number(value + 4 * addr_cells, image->arch.ima_buffer_size,
+			   size_cells);
+	if (ret)
+		return ret;
+
+	ret = fdt_setprop(fdt, chosen_node, "linux,ima-kexec-buffer", value,
+			  entry_size);
+	if (ret < 0)
+		return -EINVAL;
+
+	ret = fdt_add_mem_rsv(fdt, image->arch.ima_buffer_addr,
+			      image->arch.ima_buffer_size);
+	if (ret)
+		return -EINVAL;
+
+	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
+		 image->arch.ima_buffer_addr, image->arch.ima_buffer_size);
+
+	return 0;
+}
+#else /* CONFIG_IMA_KEXEC */
+static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
+				   int chosen_node)
+{
+	return 0;
+}
+#endif /* CONFIG_IMA_KEXEC */
+
 /*
  * of_kexec_setup_new_fdt - modify /chosen and memory reservation for the next kernel
  *
@@ -219,6 +395,11 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 	}
 
 	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
+	if (ret)
+		goto out;
+
+	remove_ima_buffer(fdt, chosen_node);
+	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
 
 out:
 	if (ret)
@@ -226,3 +407,57 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 
 	return 0;
 }
+
+/**
+ * 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.
+ */
+int ima_get_kexec_buffer(void **addr, size_t *size)
+{
+	int ret, len;
+	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);
+	if (ret)
+		return ret;
+
+	*addr = __va(tmp_addr);
+	*size = tmp_size;
+
+	return 0;
+}
+
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
+ */
+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 = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+	if (ret)
+		return ret;
+
+	ret = of_remove_property(of_chosen, prop);
+	if (ret)
+		return ret;
+
+	return memblock_free(addr, size);
+
+}
diff --git a/include/linux/of.h b/include/linux/of.h
index 3375f5295875..48eb2d05c0ec 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -562,6 +562,8 @@ 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 ima_get_kexec_buffer(void **addr, size_t *size);
+int ima_free_kexec_buffer(void);
 
 #else /* CONFIG_OF */
 
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 6ebefec616e4..7c3947ad3773 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -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 };
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 38bcd7543e27..8a6712981dee 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -10,6 +10,7 @@
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 #include <linux/kexec.h>
+#include <linux/of.h>
 #include <linux/ima.h>
 #include "ima.h"
 
-- 
2.29.2

[PATCH v13 3/6] kexec: Use fdt_appendprop_addrrange() to add ima buffer to FDT

[Lakshmi Ramasubramanian]

fdt_appendprop_addrrange() function adds a property, with the given name,
to the device tree at the given node offset, and also sets the address
and size of the property. This function should be used to add
"linux,ima-kexec-buffer" property to the device tree and set the address
and size of the IMA measurement buffer, instead of using custom function.

Use fdt_appendprop_addrrange() to add  "linux,ima-kexec-buffer" property
to the device tree. This property holds the address and size of
the IMA measurement buffer that needs to be passed from the current
kernel to the next kernel across kexec system call.

Remove custom code that is used in setup_ima_buffer() to add
"linux,ima-kexec-buffer" property to the device tree.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 drivers/of/kexec.c | 57 ++++------------------------------------------
 1 file changed, 5 insertions(+), 52 deletions(-)

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 33d97106f176..0031491d9aeb 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -147,36 +147,6 @@ static inline void remove_ima_buffer(void *fdt, int chosen_node) {}
 #endif /* CONFIG_HAVE_IMA_KEXEC */
 
 #ifdef CONFIG_IMA_KEXEC
-/**
- * write_number - Convert number to big-endian format
- *
- * @p:		Buffer to write the number to
- * @value:	Number to convert
- * @cells:	Number of cells
- *
- * Return: 0 on success, or negative errno on error.
- */
-static int write_number(void *p, u64 value, int cells)
-{
-	if (cells == 1) {
-		u32 tmp;
-
-		if (value > U32_MAX)
-			return -EINVAL;
-
-		tmp = cpu_to_be32(value);
-		memcpy(p, &tmp, sizeof(tmp));
-	} else if (cells == 2) {
-		u64 tmp;
-
-		tmp = cpu_to_be64(value);
-		memcpy(p, &tmp, sizeof(tmp));
-	} else
-		return -EINVAL;
-
-	return 0;
-}
-
 /**
  * setup_ima_buffer - add IMA buffer information to the fdt
  * @image:		kexec image being loaded.
@@ -188,32 +158,15 @@ static int write_number(void *p, u64 value, int cells)
 static int setup_ima_buffer(const struct kimage *image, void *fdt,
 			    int chosen_node)
 {
-	int ret, addr_cells, size_cells, entry_size;
-	u8 value[16];
+	int ret;
 
 	if (!image->arch.ima_buffer_size)
 		return 0;
 
-	ret = get_addr_size_cells(&addr_cells, &size_cells);
-	if (ret)
-		return ret;
-
-	entry_size = 4 * (addr_cells + size_cells);
-
-	if (entry_size > sizeof(value))
-		return -EINVAL;
-
-	ret = write_number(value, image->arch.ima_buffer_addr, addr_cells);
-	if (ret)
-		return ret;
-
-	ret = write_number(value + 4 * addr_cells, image->arch.ima_buffer_size,
-			   size_cells);
-	if (ret)
-		return ret;
-
-	ret = fdt_setprop(fdt, chosen_node, "linux,ima-kexec-buffer", value,
-			  entry_size);
+	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				       "linux,ima-kexec-buffer",
+				       image->arch.ima_buffer_addr,
+				       image->arch.ima_buffer_size);
 	if (ret < 0)
 		return -EINVAL;
 
-- 
2.29.2

[PATCH v13 4/6] powerpc: Delete unused function delete_fdt_mem_rsv()

[Lakshmi Ramasubramanian]

delete_fdt_mem_rsv() defined in "arch/powerpc/kexec/file_load.c"
has been renamed to fdt_find_and_del_mem_rsv(), and moved to
"drivers/of/kexec.c".

Remove delete_fdt_mem_rsv() in "arch/powerpc/kexec/file_load.c".

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/powerpc/include/asm/kexec.h |  1 -
 arch/powerpc/kexec/file_load.c   | 32 --------------------------------
 2 files changed, 33 deletions(-)

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index dbf09d2f36d0..d4b7d2d6191d 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -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;
diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
index 9f3ec0b239ef..f37652ccb8a1 100644
--- a/arch/powerpc/kexec/file_load.c
+++ b/arch/powerpc/kexec/file_load.c
@@ -109,38 +109,6 @@ 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.
-- 
2.29.2

[PATCH v13 5/6] arm64: Free DTB buffer if fdt_open_into() fails

[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.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/arm64/kernel/machine_kexec_file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 7de9c47dee7c..3e045cd62451 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -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);
-- 
2.29.2

[PATCH v13 6/6] arm64: Add IMA log information in kimage used for kexec

[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.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/arm64/Kconfig             | 1 +
 arch/arm64/include/asm/kexec.h | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1d466addb078..c85d18b1f2fd 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -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
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..2bd19ccb6c43 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -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;
-- 
2.29.2

Re: [PATCH v13 1/6] ima: Move arch_ima_add_kexec_buffer() to ima

[Mimi Zohar]

On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
> arch_ima_add_kexec_buffer() defined in "arch/powerpc/kexec/ima.c"
> sets up the address and size of the IMA measurement list in
> the architecture specific fields in kimage struct. This function does not
> have architecture specific code, but is currently limited to powerpc.
> 
> Move arch_ima_add_kexec_buffer() to ima.
> 
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>

Acked-by: Mimi Zohar <zohar@linux.ibm.com>

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Mimi Zohar]

Hi Lakshmi,

On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
> 
> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> index 4aff6846c772..b6c52608cb49 100644
> --- a/arch/powerpc/kexec/Makefile
> +++ b/arch/powerpc/kexec/Makefile
> @@ -9,13 +9,6 @@ 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

Notice how "kexec/ima.o" is only included if the architecture supports
it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
configured, is the IMA measurement list carried across kexec.  After
moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
how drivers/of/Kconfig includes kexec.o:

obj-$(CONFIG_KEXEC_FILE) += kexec.o

It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
functions defined in ima.c being moved to kexec.o be defined within a
CONFIG_HAVE_IMA_KEXEC ifdef?

thanks,

Mimi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

On 12/22/20 6:26 AM, Mimi Zohar wrote:

Hi Mimi,

> 
> On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
>>
>> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
>> index 4aff6846c772..b6c52608cb49 100644
>> --- a/arch/powerpc/kexec/Makefile
>> +++ b/arch/powerpc/kexec/Makefile
>> @@ -9,13 +9,6 @@ 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
> 
> Notice how "kexec/ima.o" is only included if the architecture supports
> it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
> configured, is the IMA measurement list carried across kexec.  After
> moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
> how drivers/of/Kconfig includes kexec.o:
> 
> obj-$(CONFIG_KEXEC_FILE) += kexec.o
> 
> It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
> functions defined in ima.c being moved to kexec.o be defined within a
> CONFIG_HAVE_IMA_KEXEC ifdef?
> 

Thanks for reviewing the changes.

In "drivers/of/kexec.c" the function remove_ima_buffer() is defined 
under "#ifdef CONFIG_HAVE_IMA_KEXEC"

setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same 
way it was defined in "arch/powerpc/kexec/ima.c".

As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as 
defined in "security/integrity/ima/Kconfig").

ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally 
defined in "drivers/of/kexec.c" even though they are called only when 
CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to 
be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC"

Rob/Mimi/Thiago - Please let me know if you have other comments in the 
v13 patches. Will address those as well and post v14.

thanks,
  -lakshmi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Mimi Zohar]

On Tue, 2020-12-22 at 10:53 -0800, Lakshmi Ramasubramanian wrote:
> On 12/22/20 6:26 AM, Mimi Zohar wrote:
> 
> Hi Mimi,
> 
> > 
> > On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
> >>
> >> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> >> index 4aff6846c772..b6c52608cb49 100644
> >> --- a/arch/powerpc/kexec/Makefile
> >> +++ b/arch/powerpc/kexec/Makefile
> >> @@ -9,13 +9,6 @@ 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
> > 
> > Notice how "kexec/ima.o" is only included if the architecture supports
> > it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
> > configured, is the IMA measurement list carried across kexec.  After
> > moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
> > how drivers/of/Kconfig includes kexec.o:
> > 
> > obj-$(CONFIG_KEXEC_FILE) += kexec.o
> > 
> > It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
> > functions defined in ima.c being moved to kexec.o be defined within a
> > CONFIG_HAVE_IMA_KEXEC ifdef?
> > 
> 
> Thanks for reviewing the changes.
> 
> In "drivers/of/kexec.c" the function remove_ima_buffer() is defined 
> under "#ifdef CONFIG_HAVE_IMA_KEXEC"
> 
> setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same 
> way it was defined in "arch/powerpc/kexec/ima.c".
> 
> As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as 
> defined in "security/integrity/ima/Kconfig").
> 
> ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally 
> defined in "drivers/of/kexec.c" even though they are called only when 
> CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to 
> be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC"

The issue is the reverse.  CONFIG_HAVE_IMA_KEXEC may be enabled without
CONFIG_IMA_KEXEC being enabled.  This allows the architecture to
support carrying the measurement list across kexec, but requires
enabling it at build time.

Only if CONFIG_HAVE_IMA_KEXEC is enabled should any of these functions
be compiled at build.  This allows restoring the previous IMA
measurement list, even if CONFIG_IMA_KEXEC is not enabled.

Only if CONFIG_IMA_KEXEC is enabled, should carrying the measurement
list across kexec be enabled.  See how arch_ima_add_kexec_buffer,
write_number, setup_ima_buffer are ifdef'ed in
arch/powerpc/kexec/ima.c.

Mimi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

On 12/22/20 11:45 AM, Mimi Zohar wrote:
> On Tue, 2020-12-22 at 10:53 -0800, Lakshmi Ramasubramanian wrote:
>> On 12/22/20 6:26 AM, Mimi Zohar wrote:
>>
>> Hi Mimi,
>>
>>>
>>> On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
>>>>
>>>> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
>>>> index 4aff6846c772..b6c52608cb49 100644
>>>> --- a/arch/powerpc/kexec/Makefile
>>>> +++ b/arch/powerpc/kexec/Makefile
>>>> @@ -9,13 +9,6 @@ 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
>>>
>>> Notice how "kexec/ima.o" is only included if the architecture supports
>>> it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
>>> configured, is the IMA measurement list carried across kexec.  After
>>> moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
>>> how drivers/of/Kconfig includes kexec.o:
>>>
>>> obj-$(CONFIG_KEXEC_FILE) += kexec.o
>>>
>>> It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
>>> functions defined in ima.c being moved to kexec.o be defined within a
>>> CONFIG_HAVE_IMA_KEXEC ifdef?
>>>
>>
>> Thanks for reviewing the changes.
>>
>> In "drivers/of/kexec.c" the function remove_ima_buffer() is defined
>> under "#ifdef CONFIG_HAVE_IMA_KEXEC"
>>
>> setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same
>> way it was defined in "arch/powerpc/kexec/ima.c".
>>
>> As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as
>> defined in "security/integrity/ima/Kconfig").
>>
>> ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally
>> defined in "drivers/of/kexec.c" even though they are called only when
>> CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to
>> be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC"
> 
> The issue is the reverse.  CONFIG_HAVE_IMA_KEXEC may be enabled without
> CONFIG_IMA_KEXEC being enabled.  This allows the architecture to
> support carrying the measurement list across kexec, but requires
> enabling it at build time.
> 
> Only if CONFIG_HAVE_IMA_KEXEC is enabled should any of these functions
> be compiled at build.  This allows restoring the previous IMA
> measurement list, even if CONFIG_IMA_KEXEC is not enabled.
> 
> Only if CONFIG_IMA_KEXEC is enabled, should carrying the measurement
> list across kexec be enabled.  See how arch_ima_add_kexec_buffer,
> write_number, setup_ima_buffer are ifdef'ed in
> arch/powerpc/kexec/ima.c.
> 

Yes - I agree. I will make the following changes:

=> Enable the functions moved from "arch/powerpc/kexec/ima.c" to 
"drivers/of/kexec.c" only when CONFIG_HAVE_IMA_KEXEC is enabled.

=> Also, compile write_number() and setup_ima_buffer() only when 
CONFIG_IMA_KEXEC is enabled.

thanks,
  -lakshmi

Re: [PATCH v13 1/6] ima: Move arch_ima_add_kexec_buffer() to ima

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> arch_ima_add_kexec_buffer() defined in "arch/powerpc/kexec/ima.c"
> sets up the address and size of the IMA measurement list in
> the architecture specific fields in kimage struct. This function does not
> have architecture specific code, but is currently limited to powerpc.
>
> Move arch_ima_add_kexec_buffer() to ima.
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/powerpc/include/asm/ima.h     |  3 ---
>  arch/powerpc/kexec/ima.c           | 17 -----------------
>  security/integrity/ima/ima_kexec.c | 22 ++++++++++++++++++++++
>  3 files changed, 22 insertions(+), 20 deletions(-)

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Just one nit below.

Also, I just noticed that this patch series hasn't been cc'd to the linuxppc-dev
mailing list. You should do that, since it affects powerpc code. The
powerpc maintainers are being copied so at least they've been made aware
of it, but that isn't enough.

> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> index 121de3e04af2..38bcd7543e27 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -10,6 +10,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/vmalloc.h>
>  #include <linux/kexec.h>
> +#include <linux/ima.h>
>  #include "ima.h"
>  
>  #ifdef CONFIG_IMA_KEXEC

There's no need to add this include.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
> and freeing the resources required to carry over the IMA measurement
> list from the current kernel to the next kernel across kexec system call.
> These functions do not have architecture specific code, but are
> currently limited to powerpc.
>
> Move setup_ima_buffer() call into of_kexec_setup_new_fdt() defined in
> "drivers/of/kexec.c".
>
> Move the remaining architecture independent functions from
> "arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c".
> Delete "arch/powerpc/kexec/ima.c" and "arch/powerpc/include/asm/ima.h".
> Remove references to the deleted files in powerpc and in ima.
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/powerpc/include/asm/ima.h     |  27 ----
>  arch/powerpc/kexec/Makefile        |   7 -
>  arch/powerpc/kexec/file_load.c     |   7 -
>  arch/powerpc/kexec/ima.c           | 202 -------------------------
>  drivers/of/kexec.c                 | 235 +++++++++++++++++++++++++++++
>  include/linux/of.h                 |   2 +
>  security/integrity/ima/ima.h       |   4 -
>  security/integrity/ima/ima_kexec.c |   1 +
>  8 files changed, 238 insertions(+), 247 deletions(-)
>  delete mode 100644 arch/powerpc/include/asm/ima.h
>  delete mode 100644 arch/powerpc/kexec/ima.c

This looks good, provided the changes from the discussion with Mimi are
made. Also, minor nits below.

> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 6ebefec616e4..7c3947ad3773 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -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 };

This belongs in patch 1.

> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> index 38bcd7543e27..8a6712981dee 100644
> --- a/security/integrity/ima/ima_kexec.c
> +++ b/security/integrity/ima/ima_kexec.c
> @@ -10,6 +10,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/vmalloc.h>
>  #include <linux/kexec.h>
> +#include <linux/of.h>
>  #include <linux/ima.h>
>  #include "ima.h"

This include isn't necessary.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> On 12/22/20 11:45 AM, Mimi Zohar wrote:
>> On Tue, 2020-12-22 at 10:53 -0800, Lakshmi Ramasubramanian wrote:
>>> On 12/22/20 6:26 AM, Mimi Zohar wrote:
>>>
>>> Hi Mimi,
>>>
>>>>
>>>> On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
>>>>>
>>>>> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
>>>>> index 4aff6846c772..b6c52608cb49 100644
>>>>> --- a/arch/powerpc/kexec/Makefile
>>>>> +++ b/arch/powerpc/kexec/Makefile
>>>>> @@ -9,13 +9,6 @@ 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
>>>>
>>>> Notice how "kexec/ima.o" is only included if the architecture supports
>>>> it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
>>>> configured, is the IMA measurement list carried across kexec.  After
>>>> moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
>>>> how drivers/of/Kconfig includes kexec.o:
>>>>
>>>> obj-$(CONFIG_KEXEC_FILE) += kexec.o
>>>>
>>>> It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
>>>> functions defined in ima.c being moved to kexec.o be defined within a
>>>> CONFIG_HAVE_IMA_KEXEC ifdef?
>>>>
>>>
>>> Thanks for reviewing the changes.
>>>
>>> In "drivers/of/kexec.c" the function remove_ima_buffer() is defined
>>> under "#ifdef CONFIG_HAVE_IMA_KEXEC"
>>>
>>> setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same
>>> way it was defined in "arch/powerpc/kexec/ima.c".
>>>
>>> As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as
>>> defined in "security/integrity/ima/Kconfig").
>>>
>>> ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally
>>> defined in "drivers/of/kexec.c" even though they are called only when
>>> CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to
>>> be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC"
>> The issue is the reverse.  CONFIG_HAVE_IMA_KEXEC may be enabled without
>> CONFIG_IMA_KEXEC being enabled.  This allows the architecture to
>> support carrying the measurement list across kexec, but requires
>> enabling it at build time.
>> Only if CONFIG_HAVE_IMA_KEXEC is enabled should any of these functions
>> be compiled at build.  This allows restoring the previous IMA
>> measurement list, even if CONFIG_IMA_KEXEC is not enabled.
>> Only if CONFIG_IMA_KEXEC is enabled, should carrying the measurement
>> list across kexec be enabled.  See how arch_ima_add_kexec_buffer,
>> write_number, setup_ima_buffer are ifdef'ed in
>> arch/powerpc/kexec/ima.c.
>> 
>
> Yes - I agree. I will make the following changes:
>
> => Enable the functions moved from "arch/powerpc/kexec/ima.c" to
> "drivers/of/kexec.c" only when CONFIG_HAVE_IMA_KEXEC is enabled.
>
> => Also, compile write_number() and setup_ima_buffer() only when
> CONFIG_IMA_KEXEC is enabled.

Sounds good, with one additional change:

So far, CONFIG_HAVE_IMA_KEXEC was tested only in files that were built
when CONFIG_IMA was set. With this series this is not the case anymore
(in drivers/of/kexec.c). The simplest way to keep this consistent is to
only enable CONFIG_HAVE_IMA_KEXEC if CONFIG_IMA is also set.

For example, with this:

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..4ddd17215ecf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -548,7 +548,7 @@ config KEXEC
 config KEXEC_FILE
 	bool "kexec file based system call"
 	select KEXEC_CORE
-	select HAVE_IMA_KEXEC
+	select HAVE_IMA_KEXEC if IMA
 	select BUILD_BIN2C
 	select KEXEC_ELF
 	depends on PPC64

And then the same thing on the arm64 patch.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Thiago Jung Bauermann]

Actually, I have one more comment on this patch:

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
> index 956bcb2d1ec2..9f3ec0b239ef 100644
> --- a/arch/powerpc/kexec/file_load.c
> +++ b/arch/powerpc/kexec/file_load.c
> @@ -20,7 +20,6 @@
>  #include <linux/of_fdt.h>
>  #include <linux/libfdt.h>
>  #include <asm/setup.h>
> -#include <asm/ima.h>
>  
>  #define SLAVE_CODE_SIZE		256	/* First 0x100 bytes */
>  
> @@ -163,12 +162,6 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
>  	if (ret)
>  		goto err;
>  
> -	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
> -	if (ret) {
> -		pr_err("Error setting up the new device tree.\n");
> -		return ret;
> -	}
> -
>  	return 0;
>  
>  err:

With this change, setup_new_fdt() is nothing more than a call to
of_kexec_setup_new_fdt(). It should be removed, and its caller should
call of_kexec_setup_new_fdt() directly.

This change could be done in patch 4 of this series, to keep this patch
simpler.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 3/6] kexec: Use fdt_appendprop_addrrange() to add ima buffer to FDT

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> fdt_appendprop_addrrange() function adds a property, with the given name,
> to the device tree at the given node offset, and also sets the address
> and size of the property. This function should be used to add
> "linux,ima-kexec-buffer" property to the device tree and set the address
> and size of the IMA measurement buffer, instead of using custom function.
>
> Use fdt_appendprop_addrrange() to add  "linux,ima-kexec-buffer" property
> to the device tree. This property holds the address and size of
> the IMA measurement buffer that needs to be passed from the current
> kernel to the next kernel across kexec system call.
>
> Remove custom code that is used in setup_ima_buffer() to add
> "linux,ima-kexec-buffer" property to the device tree.
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  drivers/of/kexec.c | 57 ++++------------------------------------------
>  1 file changed, 5 insertions(+), 52 deletions(-)

This is a nice improvement, thanks.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 4/6] powerpc: Delete unused function delete_fdt_mem_rsv()

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> delete_fdt_mem_rsv() defined in "arch/powerpc/kexec/file_load.c"
> has been renamed to fdt_find_and_del_mem_rsv(), and moved to
> "drivers/of/kexec.c".
>
> Remove delete_fdt_mem_rsv() in "arch/powerpc/kexec/file_load.c".
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/powerpc/include/asm/kexec.h |  1 -
>  arch/powerpc/kexec/file_load.c   | 32 --------------------------------
>  2 files changed, 33 deletions(-)

As I mentioned in the other email, this patch could remove
setup_new_fdt() as well.

I'm a bit ambivalent on whether this patch should be squashed with
patch 2 or left on its own, but I tend toward the latter option because
patch 2 is big enough already.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 5/6] arm64: Free DTB buffer if fdt_open_into() fails

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> 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.
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/arm64/kernel/machine_kexec_file.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 6/6] arm64: Add IMA log information in kimage used for kexec

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> 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.
>
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/arm64/Kconfig             | 1 +
>  arch/arm64/include/asm/kexec.h | 5 +++++
>  2 files changed, 6 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1d466addb078..c85d18b1f2fd 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -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

As I suggested in the other email, this should be:

	select HAVE_IMA_KEXEC if IMA

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

On 12/22/20 4:48 PM, Thiago Jung Bauermann wrote:
> 
> Actually, I have one more comment on this patch:
> 
> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> 
>> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
>> index 956bcb2d1ec2..9f3ec0b239ef 100644
>> --- a/arch/powerpc/kexec/file_load.c
>> +++ b/arch/powerpc/kexec/file_load.c
>> @@ -20,7 +20,6 @@
>>   #include <linux/of_fdt.h>
>>   #include <linux/libfdt.h>
>>   #include <asm/setup.h>
>> -#include <asm/ima.h>
>>   
>>   #define SLAVE_CODE_SIZE		256	/* First 0x100 bytes */
>>   
>> @@ -163,12 +162,6 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
>>   	if (ret)
>>   		goto err;
>>   
>> -	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
>> -	if (ret) {
>> -		pr_err("Error setting up the new device tree.\n");
>> -		return ret;
>> -	}
>> -
>>   	return 0;
>>   
>>   err:
> 
> With this change, setup_new_fdt() is nothing more than a call to
> of_kexec_setup_new_fdt(). It should be removed, and its caller should
> call of_kexec_setup_new_fdt() directly.
> 
> This change could be done in patch 4 of this series, to keep this patch
> simpler.
> 

Sure Thiago - I will make that change.

thanks,
  -lakshmi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

On 12/22/20 4:19 PM, Thiago Jung Bauermann wrote:
> 
> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> 
>> The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
>> and freeing the resources required to carry over the IMA measurement
>> list from the current kernel to the next kernel across kexec system call.
>> These functions do not have architecture specific code, but are
>> currently limited to powerpc.
>>
>> Move setup_ima_buffer() call into of_kexec_setup_new_fdt() defined in
>> "drivers/of/kexec.c".
>>
>> Move the remaining architecture independent functions from
>> "arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c".
>> Delete "arch/powerpc/kexec/ima.c" and "arch/powerpc/include/asm/ima.h".
>> Remove references to the deleted files in powerpc and in ima.
>>
>> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
>> ---
>>   arch/powerpc/include/asm/ima.h     |  27 ----
>>   arch/powerpc/kexec/Makefile        |   7 -
>>   arch/powerpc/kexec/file_load.c     |   7 -
>>   arch/powerpc/kexec/ima.c           | 202 -------------------------
>>   drivers/of/kexec.c                 | 235 +++++++++++++++++++++++++++++
>>   include/linux/of.h                 |   2 +
>>   security/integrity/ima/ima.h       |   4 -
>>   security/integrity/ima/ima_kexec.c |   1 +
>>   8 files changed, 238 insertions(+), 247 deletions(-)
>>   delete mode 100644 arch/powerpc/include/asm/ima.h
>>   delete mode 100644 arch/powerpc/kexec/ima.c
> 
> This looks good, provided the changes from the discussion with Mimi are
> made. Also, minor nits below.

I will address the changes Mimi had stated.

> 
>> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
>> index 6ebefec616e4..7c3947ad3773 100644
>> --- a/security/integrity/ima/ima.h
>> +++ b/security/integrity/ima/ima.h
>> @@ -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 };
> 
> This belongs in patch 1.

No - the reference to "asm/ima.h" cannot be removed in Patch #1 since 
ima_get_kexec_buffer() and ima_free_kexec_buffer() are still declared in 
this header. They are moved in this patch only (Patch #2).

>> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
>> index 38bcd7543e27..8a6712981dee 100644
>> --- a/security/integrity/ima/ima_kexec.c
>> +++ b/security/integrity/ima/ima_kexec.c
>> @@ -10,6 +10,7 @@
>>   #include <linux/seq_file.h>
>>   #include <linux/vmalloc.h>
>>   #include <linux/kexec.h>
>> +#include <linux/of.h>
>>   #include <linux/ima.h>
>>   #include "ima.h"
> 
> This include isn't necessary.

This change is necessary because ima_get_kexec_buffer() and 
ima_free_kexec_buffer() are now declared in "linux/of.h".

  -lakshmi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Lakshmi Ramasubramanian]

On 12/22/20 4:40 PM, Thiago Jung Bauermann wrote:
> 
> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> 
>> On 12/22/20 11:45 AM, Mimi Zohar wrote:
>>> On Tue, 2020-12-22 at 10:53 -0800, Lakshmi Ramasubramanian wrote:
>>>> On 12/22/20 6:26 AM, Mimi Zohar wrote:
>>>>
>>>> Hi Mimi,
>>>>
>>>>>
>>>>> On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote:
>>>>>>
>>>>>> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
>>>>>> index 4aff6846c772..b6c52608cb49 100644
>>>>>> --- a/arch/powerpc/kexec/Makefile
>>>>>> +++ b/arch/powerpc/kexec/Makefile
>>>>>> @@ -9,13 +9,6 @@ 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
>>>>>
>>>>> Notice how "kexec/ima.o" is only included if the architecture supports
>>>>> it and IMA is configured.  In addition only if CONFIG_IMA_KEXEC is
>>>>> configured, is the IMA measurement list carried across kexec.  After
>>>>> moving the rest of ima.c to drivers/of/kexec.c, this changes.   Notice
>>>>> how drivers/of/Kconfig includes kexec.o:
>>>>>
>>>>> obj-$(CONFIG_KEXEC_FILE) += kexec.o
>>>>>
>>>>> It is not dependent on CONFIG_HAVE_IMA_KEXEC.  Shouldn't all of the
>>>>> functions defined in ima.c being moved to kexec.o be defined within a
>>>>> CONFIG_HAVE_IMA_KEXEC ifdef?
>>>>>
>>>>
>>>> Thanks for reviewing the changes.
>>>>
>>>> In "drivers/of/kexec.c" the function remove_ima_buffer() is defined
>>>> under "#ifdef CONFIG_HAVE_IMA_KEXEC"
>>>>
>>>> setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same
>>>> way it was defined in "arch/powerpc/kexec/ima.c".
>>>>
>>>> As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as
>>>> defined in "security/integrity/ima/Kconfig").
>>>>
>>>> ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally
>>>> defined in "drivers/of/kexec.c" even though they are called only when
>>>> CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to
>>>> be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC"
>>> The issue is the reverse.  CONFIG_HAVE_IMA_KEXEC may be enabled without
>>> CONFIG_IMA_KEXEC being enabled.  This allows the architecture to
>>> support carrying the measurement list across kexec, but requires
>>> enabling it at build time.
>>> Only if CONFIG_HAVE_IMA_KEXEC is enabled should any of these functions
>>> be compiled at build.  This allows restoring the previous IMA
>>> measurement list, even if CONFIG_IMA_KEXEC is not enabled.
>>> Only if CONFIG_IMA_KEXEC is enabled, should carrying the measurement
>>> list across kexec be enabled.  See how arch_ima_add_kexec_buffer,
>>> write_number, setup_ima_buffer are ifdef'ed in
>>> arch/powerpc/kexec/ima.c.
>>>
>>
>> Yes - I agree. I will make the following changes:
>>
>> => Enable the functions moved from "arch/powerpc/kexec/ima.c" to
>> "drivers/of/kexec.c" only when CONFIG_HAVE_IMA_KEXEC is enabled.
>>
>> => Also, compile write_number() and setup_ima_buffer() only when
>> CONFIG_IMA_KEXEC is enabled.
> 
> Sounds good, with one additional change:
> 
> So far, CONFIG_HAVE_IMA_KEXEC was tested only in files that were built
> when CONFIG_IMA was set. With this series this is not the case anymore
> (in drivers/of/kexec.c). The simplest way to keep this consistent is to
> only enable CONFIG_HAVE_IMA_KEXEC if CONFIG_IMA is also set.
> 
> For example, with this:
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index e9f13fe08492..4ddd17215ecf 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -548,7 +548,7 @@ config KEXEC
>   config KEXEC_FILE
>   	bool "kexec file based system call"
>   	select KEXEC_CORE
> -	select HAVE_IMA_KEXEC
> +	select HAVE_IMA_KEXEC if IMA
>   	select BUILD_BIN2C
>   	select KEXEC_ELF
>   	depends on PPC64
> 
> And then the same thing on the arm64 patch.

This is a good idea Thiago - I will make this change in the Kconfig for 
both powerpc and arm64.

thanks,
  -lakshmi

Re: [PATCH v13 4/6] powerpc: Delete unused function delete_fdt_mem_rsv()

[Lakshmi Ramasubramanian]

On 12/22/20 5:08 PM, Thiago Jung Bauermann wrote:
> 
> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> 
>> delete_fdt_mem_rsv() defined in "arch/powerpc/kexec/file_load.c"
>> has been renamed to fdt_find_and_del_mem_rsv(), and moved to
>> "drivers/of/kexec.c".
>>
>> Remove delete_fdt_mem_rsv() in "arch/powerpc/kexec/file_load.c".
>>
>> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
>> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
>> ---
>>   arch/powerpc/include/asm/kexec.h |  1 -
>>   arch/powerpc/kexec/file_load.c   | 32 --------------------------------
>>   2 files changed, 33 deletions(-)
> 
> As I mentioned in the other email, this patch could remove
> setup_new_fdt() as well.
> 
> I'm a bit ambivalent on whether this patch should be squashed with
> patch 2 or left on its own, but I tend toward the latter option because
> patch 2 is big enough already.
> 

I also think Patch #2 is already big enough - I don't want to make more 
changes in that patch.

I will remove delete_fdt_mem_rsv() and setup_new_fdt() in this patch 
(Patch #4) and call of_kexec_setup_new_fdt() directly (in 
setup_new_fdt_ppc64()).

thanks,
  -lakshmi

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Thiago Jung Bauermann]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> On 12/22/20 4:19 PM, Thiago Jung Bauermann wrote:
>> Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
>> 
>>> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
>>> index 6ebefec616e4..7c3947ad3773 100644
>>> --- a/security/integrity/ima/ima.h
>>> +++ b/security/integrity/ima/ima.h
>>> @@ -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 };
>> This belongs in patch 1.
>
> No - the reference to "asm/ima.h" cannot be removed in Patch #1 since
> ima_get_kexec_buffer() and ima_free_kexec_buffer() are still declared in 
> this header. They are moved in this patch only (Patch #2).

Indeed, you are right. My mistake.

>>> diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
>>> index 38bcd7543e27..8a6712981dee 100644
>>> --- a/security/integrity/ima/ima_kexec.c
>>> +++ b/security/integrity/ima/ima_kexec.c
>>> @@ -10,6 +10,7 @@
>>>   #include <linux/seq_file.h>
>>>   #include <linux/vmalloc.h>
>>>   #include <linux/kexec.h>
>>> +#include <linux/of.h>
>>>   #include <linux/ima.h>
>>>   #include "ima.h"
>> This include isn't necessary.
>
> This change is necessary because ima_get_kexec_buffer() and
> ima_free_kexec_buffer() are now declared in "linux/of.h".

You are right here as well. Before I made the suggestion, I had tested
building the kernel without the include above and it worked fine, but
that's because <linux/of.h> is being included indirectly by some other
header file. It's better to include it explicitly.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c

[Rob Herring]

On Sat, Dec 19, 2020 at 09:57:09AM -0800, Lakshmi Ramasubramanian wrote:
> The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
> and freeing the resources required to carry over the IMA measurement
> list from the current kernel to the next kernel across kexec system call.
> These functions do not have architecture specific code, but are
> currently limited to powerpc.
> 
> Move setup_ima_buffer() call into of_kexec_setup_new_fdt() defined in
> "drivers/of/kexec.c".
> 
> Move the remaining architecture independent functions from
> "arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c".
> Delete "arch/powerpc/kexec/ima.c" and "arch/powerpc/include/asm/ima.h".
> Remove references to the deleted files in powerpc and in ima.
> 
> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
>  arch/powerpc/include/asm/ima.h     |  27 ----
>  arch/powerpc/kexec/Makefile        |   7 -
>  arch/powerpc/kexec/file_load.c     |   7 -
>  arch/powerpc/kexec/ima.c           | 202 -------------------------
>  drivers/of/kexec.c                 | 235 +++++++++++++++++++++++++++++
>  include/linux/of.h                 |   2 +
>  security/integrity/ima/ima.h       |   4 -
>  security/integrity/ima/ima_kexec.c |   1 +
>  8 files changed, 238 insertions(+), 247 deletions(-)
>  delete mode 100644 arch/powerpc/include/asm/ima.h
>  delete mode 100644 arch/powerpc/kexec/ima.c


> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> index 66787be081fe..33d97106f176 100644
> --- a/drivers/of/kexec.c
> +++ b/drivers/of/kexec.c
> @@ -11,6 +11,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/kexec.h>
> +#include <linux/memblock.h>
>  #include <linux/libfdt.h>
>  #include <linux/of.h>
>  #include <linux/of_fdt.h>
> @@ -59,6 +60,181 @@ static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned lon
>  	return -ENOENT;
>  }
>  
> +/**
> + * get_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.
> + */
> +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;
> +}
> +
> +/**
> + * do_get_kexec_buffer - Get address and size of device tree property
> + *
> + * @prop: Device tree property
> + * @len: Size of @prop
> + * @addr: Return address of the node
> + * @size: Return size of the node
> + *
> + * Return: 0 on success, or negative errno on error.
> + */
> +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;
> +}
> +
> +#ifdef CONFIG_HAVE_IMA_KEXEC
> +/**
> + * 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.
> + */
> +static void remove_ima_buffer(void *fdt, int chosen_node)
> +{
> +	int ret, len;
> +	unsigned long addr;
> +	size_t size;
> +	const void *prop;
> +

Should be able to do this instead of #ifdef:

if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
	return;

Otherwise, I think it looks good.

Rob