[PATCH v5 01/10] powerpc: ima: Get the kexec buffer passed by the previous kernel
Mimi Zohar
zohar at linux.vnet.ibm.com
Mon Sep 26 10:30:20 PDT 2016
From: Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
The IMA kexec buffer allows the currently running kernel to pass
the measurement list via a kexec segment to the kernel that will be
kexec'd. The second kernel can check whether the previous kernel sent
the buffer and retrieve it.
This is the architecture-specific part which enables IMA to receive the
measurement list passed by the previous kernel. It will be used in the
next patch.
The change in machine_kexec_64.c is to factor out the logic of removing
an FDT memory reservation so that it can be used by remove_ima_buffer.
Changelog v5:
- New patch in this version. This code was previously in the kexec buffer
handover patch series.
Changelog relative to kexec handover patches v5:
- Added CONFIG_HAVE_IMA_KEXEC.
- Added arch/powerpc/include/asm/ima.h.
- Moved code to arch/powerpc/kernel/ima_kexec.c.
- Renamed functions to variations of ima_kexec_buffer instead of
variations of kexec_handover_buffer.
- Use a single property /chosen/linux,ima-kexec-buffer containing
the buffer address and length, instead of
/chosen/linux,kexec-handover-buffer-{start,end}.
- Use #address-cells and #size-cells to read the DT property.
- Use size_t instead of unsigned long for size arguments.
- Always remove linux,ima-kexec-buffer and its memory reservation
when preparing a device tree for kexec_file_load.
Signed-off-by: Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
---
arch/Kconfig | 3 +
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/ima.h | 13 ++++
arch/powerpc/include/asm/kexec.h | 1 +
arch/powerpc/kernel/Makefile | 4 +
arch/powerpc/kernel/ima_kexec.c | 132 +++++++++++++++++++++++++++++++++
arch/powerpc/kernel/machine_kexec_64.c | 106 +++++++++++++-------------
7 files changed, 208 insertions(+), 52 deletions(-)
create mode 100644 arch/powerpc/include/asm/ima.h
create mode 100644 arch/powerpc/kernel/ima_kexec.c
diff --git a/arch/Kconfig b/arch/Kconfig
index e9c9334..60283562 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -5,6 +5,9 @@
config KEXEC_CORE
bool
+config HAVE_IMA_KEXEC
+ bool
+
config OPROFILE
tristate "OProfile system profiling"
depends on PROFILING
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d1ba864..17fff29 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -458,6 +458,7 @@ config KEXEC
config KEXEC_FILE
bool "kexec file based system call"
select KEXEC_CORE
+ select HAVE_IMA_KEXEC
select BUILD_BIN2C
depends on PPC64
depends on CRYPTO=y
diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
new file mode 100644
index 0000000..d5a72dd
--- /dev/null
+++ b/arch/powerpc/include/asm/ima.h
@@ -0,0 +1,13 @@
+#ifndef _ASM_POWERPC_IMA_H
+#define _ASM_POWERPC_IMA_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
+
+#endif /* _ASM_POWERPC_IMA_H */
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 73f88b5..5dda514 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -99,6 +99,7 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
unsigned long initrd_len, const char *cmdline);
bool find_debug_console(const void *fdt);
+int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
#endif /* CONFIG_KEXEC_FILE */
#else /* !CONFIG_KEXEC_CORE */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 0ee1b3f..5e0bacc 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -109,6 +109,10 @@ obj-$(CONFIG_PCI_MSI) += msi.o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o crash.o \
machine_kexec_$(BITS).o
obj-$(CONFIG_KEXEC_FILE) += kexec_elf_$(BITS).o
+ifeq ($(CONFIG_HAVE_IMA_KEXEC)$(CONFIG_IMA),yy)
+obj-y += ima_kexec.o
+endif
+
obj-$(CONFIG_AUDIT) += audit.o
obj64-$(CONFIG_AUDIT) += compat_audit.o
diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c
new file mode 100644
index 0000000..36e5a5d
--- /dev/null
+++ b/arch/powerpc/kernel/ima_kexec.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#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");
+}
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 9cd8f3b..c2e0b18 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -34,6 +34,7 @@
#include <asm/hw_breakpoint.h>
#include <asm/asm-prototypes.h>
#include <asm/kexec_elf_64.h>
+#include <asm/ima.h>
#define SLAVE_CODE_SIZE 256
@@ -657,9 +658,9 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
return 0;
}
-/*
- * setup_new_fdt() - modify /chosen and memory reservation for the next kernel
- * @fdt:
+/**
+ * setup_new_fdt() - modify /chosen and memory reservations for the next kernel
+ * @fdt: Flattened device tree for the next kernel.
* @initrd_load_addr: Address where the next initrd will be loaded.
* @initrd_len: Size of the next initrd, or 0 if there will be none.
* @cmdline: Command line for the next kernel, or NULL if there will
@@ -670,33 +671,16 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
unsigned long initrd_len, const char *cmdline)
{
- uint64_t oldfdt_addr;
- int i, ret, chosen_node;
+ int ret, chosen_node;
const void *prop;
/* Remove memory reservation for the current device tree. */
- oldfdt_addr = __pa(initial_boot_params);
- for (i = 0; i < fdt_num_mem_rsv(fdt); 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 == oldfdt_addr &&
- rsv_size == fdt_totalsize(initial_boot_params)) {
- ret = fdt_del_mem_rsv(fdt, i);
- if (ret) {
- pr_err("Error deleting fdt reservation.\n");
- return -EINVAL;
- }
-
- pr_debug("Removed old device tree reservation.\n");
- break;
- }
- }
+ ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
+ fdt_totalsize(initial_boot_params));
+ if (ret == 0)
+ pr_debug("Removed old device tree reservation.\n");
+ else if (ret != -ENOENT)
+ return ret;
chosen_node = fdt_path_offset(fdt, "/chosen");
if (chosen_node == -FDT_ERR_NOTFOUND) {
@@ -714,7 +698,7 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
/* Did we boot using an initrd? */
prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
if (prop) {
- uint64_t tmp_start, tmp_end, tmp_size, tmp_sizepg;
+ uint64_t tmp_start, tmp_end, tmp_size;
tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
@@ -730,30 +714,14 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
* reserve a multiple of PAGE_SIZE, so check for both.
*/
tmp_size = tmp_end - tmp_start;
- tmp_sizepg = round_up(tmp_size, PAGE_SIZE);
-
- /* Remove memory reservation for the current initrd. */
- for (i = 0; i < fdt_num_mem_rsv(fdt); 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 == tmp_start &&
- (rsv_size == tmp_size || rsv_size == tmp_sizepg)) {
- ret = fdt_del_mem_rsv(fdt, i);
- if (ret) {
- pr_err("Error deleting fdt reservation.\n");
- return -EINVAL;
- }
- pr_debug("Removed old initrd reservation.\n");
-
- break;
- }
- }
+ ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
+ if (ret == -ENOENT)
+ ret = delete_fdt_mem_rsv(fdt, tmp_start,
+ round_up(tmp_size, PAGE_SIZE));
+ if (ret == 0)
+ pr_debug("Removed old initrd reservation.\n");
+ else if (ret != -ENOENT)
+ return ret;
/* If there's no new initrd, delete the old initrd's info. */
if (initrd_len == 0) {
@@ -811,6 +779,8 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
}
}
+ remove_ima_buffer(fdt, chosen_node);
+
ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
if (ret) {
pr_err("Error setting up the new device tree.\n");
@@ -821,6 +791,38 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
}
/**
+ * 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;
+}
+
+/**
* find_debug_console() - find out whether there is a console for the purgatory
* @fdt: Flattened device tree to search.
*/
--
2.1.0
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