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Message-Id: <1477017898-10375-6-git-send-email-bauerman@linux.vnet.ibm.com>
Date: Fri, 21 Oct 2016 00:44:53 -0200
From: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
To: linux-security-module <linux-security-module@...r.kernel.org>
Cc: Mimi Zohar <zohar@...ux.vnet.ibm.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
linux-ima-devel@...ts.sourceforge.net,
Dave Young <dyoung@...hat.com>, kexec@...ts.infradead.org,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Subject: [PATCH v6 05/10] powerpc: ima: Send the kexec buffer to the next kernel
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.
This is the architecture-specific part of setting up the IMA kexec
buffer for the next kernel. It will be used in the next patch.
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:
- Moved code to arch/powerpc/kernel/ima_kexec.c.
- Renamed functions and struct members 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 write the DT property.
- Use size_t instead of unsigned long for size arguments.
- Use CONFIG_IMA_KEXEC to build this code only when necessary.
Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
arch/powerpc/include/asm/ima.h | 16 +++++
arch/powerpc/include/asm/kexec.h | 14 ++++-
arch/powerpc/kernel/ima_kexec.c | 91 +++++++++++++++++++++++++++++
arch/powerpc/kernel/kexec_elf_64.c | 2 +-
arch/powerpc/kernel/machine_kexec_file_64.c | 12 +++-
5 files changed, 129 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
index d5a72dd9b499..2313bdface34 100644
--- a/arch/powerpc/include/asm/ima.h
+++ b/arch/powerpc/include/asm/ima.h
@@ -1,6 +1,8 @@
#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);
@@ -10,4 +12,18 @@ void remove_ima_buffer(void *fdt, int chosen_node);
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,
+ 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/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 23056d2dc330..a49cab287acb 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -94,12 +94,22 @@ static inline bool kdump_in_progress(void)
#ifdef CONFIG_KEXEC_FILE
extern struct kexec_file_ops kexec_elf64_ops;
+#ifdef CONFIG_IMA_KEXEC
+#define ARCH_HAS_KIMAGE_ARCH
+
+struct kimage_arch {
+ phys_addr_t ima_buffer_addr;
+ size_t ima_buffer_size;
+};
+#endif
+
int setup_purgatory(struct kimage *image, const void *slave_code,
const void *fdt, unsigned long kernel_load_addr,
unsigned long fdt_load_addr, unsigned long stack_top,
int debug);
-int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
- unsigned long initrd_len, const char *cmdline);
+int setup_new_fdt(const struct kimage *image, 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 */
diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c
index 36e5a5df3804..5ea42c937ca9 100644
--- a/arch/powerpc/kernel/ima_kexec.c
+++ b/arch/powerpc/kernel/ima_kexec.c
@@ -130,3 +130,94 @@ void remove_ima_buffer(void *fdt, int chosen_node)
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 */
diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c
index dc29e0131b76..1bd1e9865835 100644
--- a/arch/powerpc/kernel/kexec_elf_64.c
+++ b/arch/powerpc/kernel/kexec_elf_64.c
@@ -206,7 +206,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
goto out;
}
- ret = setup_new_fdt(fdt, initrd_load_addr, initrd_len, cmdline);
+ ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len, cmdline);
if (ret)
goto out;
diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
index 7b13634f71bf..e4da26dabbaf 100644
--- a/arch/powerpc/kernel/machine_kexec_file_64.c
+++ b/arch/powerpc/kernel/machine_kexec_file_64.c
@@ -393,6 +393,7 @@ int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
/*
* setup_new_fdt - modify /chosen and memory reservation for the next kernel
+ * @image: kexec image being loaded.
* @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.
@@ -401,8 +402,9 @@ int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
*
* Return: 0 on success, or negative errno on error.
*/
-int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
- unsigned long initrd_len, const char *cmdline)
+int setup_new_fdt(const struct kimage *image, void *fdt,
+ unsigned long initrd_load_addr, unsigned long initrd_len,
+ const char *cmdline)
{
int ret, chosen_node;
const void *prop;
@@ -512,7 +514,11 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
}
}
- remove_ima_buffer(fdt, chosen_node);
+ ret = setup_ima_buffer(image, fdt, chosen_node);
+ if (ret) {
+ pr_err("Error setting up the new device tree.\n");
+ return ret;
+ }
ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
if (ret) {
--
2.7.4
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