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Diffstat (limited to 'arch/powerpc/kernel/ima_kexec.c')
-rw-r--r--arch/powerpc/kernel/ima_kexec.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c
new file mode 100644
index 000000000000..5ea42c937ca9
--- /dev/null
+++ b/arch/powerpc/kernel/ima_kexec.c
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Thiago Jung Bauermann <bauerman@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");
+}
+
+#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) {
+ 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 */