[PATCH v8 2/4] powerpc: Refactor kexec functions to move arch independent code to ima

Lakshmi Ramasubramanian
2020-10-30T17:44:53Z

The functions ima_get_kexec_buffer() and ima_free_kexec_buffer(),
that handle carrying forward the IMA measurement logs on kexec for
powerpc do not have architecture specific code, but they are currently
defined for powerpc only.

Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to IMA
subsystem. A later patch in this series will use these functions for
carrying forward the IMA measurement log for ARM64.

With the above refactoring arch/powerpc/kexec/ima.c contains only
functions used when CONFIG_IMA_KEXEC is enabled. Update Makefile
in arch/powerpc/kexec to include arch/powerpc/kexec/ima.c only
when CONFIG_IMA_KEXEC is enabled.

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/Makefile | 7 +---
arch/powerpc/kexec/ima.c | 56 -----------------------------
security/integrity/ima/ima_kexec.c | 57 ++++++++++++++++++++++++++++++
4 files changed, 58 insertions(+), 65 deletions(-)

diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
index 6355a85a3289..8975f5e0cab8 100644
--- a/arch/powerpc/include/asm/ima.h
+++ b/arch/powerpc/include/asm/ima.h
@@ -6,9 +6,6 @@

struct kimage;

-int ima_get_kexec_buffer(void **addr, size_t *size);
-int ima_free_kexec_buffer(void);
-
#ifdef CONFIG_IMA_KEXEC
int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
size_t size);
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 4aff6846c772..f54a9dbff4c8 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -9,12 +9,7 @@ obj-$(CONFIG_PPC32) += relocate_32.o

obj-$(CONFIG_KEXEC_FILE) += file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o

-ifdef CONFIG_HAVE_IMA_KEXEC
-ifdef CONFIG_IMA
-obj-y += ima.o
-endif
-endif
-
+obj-$(CONFIG_IMA_KEXEC) += ima.o

# Disable GCOV, KCOV & sanitizers in odd or sensitive code
GCOV_PROFILE_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
index 2b790230ea15..4fadd8d16891 100644
--- a/arch/powerpc/kexec/ima.c
+++ b/arch/powerpc/kexec/ima.c
@@ -30,61 +30,6 @@ static int get_addr_size_cells(int *addr_cells, int *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);
-
-}
-
-#ifdef CONFIG_IMA_KEXEC
/**
* arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
*
@@ -177,4 +122,3 @@ int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)

return 0;
}
-#endif /* CONFIG_IMA_KEXEC */
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 121de3e04af2..24be285ec558 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -10,8 +10,65 @@
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/memblock.h>
+#include <linux/libfdt.h>
+#include <linux/ima.h>
#include "ima.h"

+/**
+ * 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.
+ */
+static 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, FDT_PROP_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
+ */
+static int ima_free_kexec_buffer(void)
+{
+ int ret;
+ unsigned long addr;
+ size_t size;
+ struct property *prop;
+
+ prop = of_find_property(of_chosen, FDT_PROP_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);
+}
+
+
#ifdef CONFIG_IMA_KEXEC
static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
unsigned long segment_size)
--
2.29.0