The patch titled
Subject: ima: on soft reboot, save the measurement list
has been added to the -mm tree. Its filename is
ima-on-soft-reboot-save-the-measurement-list.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ima-on-soft-reboot-save-the-measurement-list.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ima-on-soft-reboot-save-the-measurement-list.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Subject: ima: on soft reboot, save the measurement list
The TPM PCRs are only reset on a hard reboot. In order to validate a
TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement list
of the running kernel must be saved and restored on boot.
This patch uses the kexec buffer passing mechanism to pass the
serialized IMA binary_runtime_measurements to the next kernel.
Link: http://lkml.kernel.org/r/1478789780-17719-7-git-send-email-zohar@xxxxxxxxxxxxxxxxxx
Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Josh Sklar <sklar@xxxxxxxxxxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Stewart Smith <stewart@xxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Andreas Steffen <andreas.steffen@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/ima.h | 12 ++
kernel/kexec_file.c | 4
security/integrity/ima/ima.h | 1
security/integrity/ima/ima_fs.c | 2
security/integrity/ima/ima_kexec.c | 117 +++++++++++++++++++++++++++
5 files changed, 135 insertions(+), 1 deletion(-)
diff -puN include/linux/ima.h~ima-on-soft-reboot-save-the-measurement-list include/linux/ima.h
--- a/include/linux/ima.h~ima-on-soft-reboot-save-the-measurement-list
+++ a/include/linux/ima.h
@@ -11,6 +11,7 @@
#define _LINUX_IMA_H
#include <linux/fs.h>
+#include <linux/kexec.h>
struct linux_binprm;
#ifdef CONFIG_IMA
@@ -23,6 +24,10 @@ extern int ima_post_read_file(struct fil
enum kernel_read_file_id id);
extern void ima_post_path_mknod(struct dentry *dentry);
+#ifdef CONFIG_IMA_KEXEC
+extern void ima_add_kexec_buffer(struct kimage *image);
+#endif
+
#else
static inline int ima_bprm_check(struct linux_binprm *bprm)
{
@@ -62,6 +67,13 @@ static inline void ima_post_path_mknod(s
#endif /* CONFIG_IMA */
+#ifndef CONFIG_IMA_KEXEC
+struct kimage;
+
+static inline void ima_add_kexec_buffer(struct kimage *image)
+{}
+#endif
+
#ifdef CONFIG_IMA_APPRAISE
extern void ima_inode_post_setattr(struct dentry *dentry);
extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
diff -puN kernel/kexec_file.c~ima-on-soft-reboot-save-the-measurement-list kernel/kexec_file.c
--- a/kernel/kexec_file.c~ima-on-soft-reboot-save-the-measurement-list
+++ a/kernel/kexec_file.c
@@ -19,6 +19,7 @@
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/fs.h>
+#include <linux/ima.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <linux/syscalls.h>
@@ -132,6 +133,9 @@ kimage_file_prepare_segments(struct kima
return ret;
image->kernel_buf_len = size;
+ /* IMA needs to pass the measurement list to the next kernel. */
+ ima_add_kexec_buffer(image);
+
/* Call arch image probe handlers */
ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
image->kernel_buf_len);
diff -puN security/integrity/ima/ima.h~ima-on-soft-reboot-save-the-measurement-list security/integrity/ima/ima.h
--- a/security/integrity/ima/ima.h~ima-on-soft-reboot-save-the-measurement-list
+++ a/security/integrity/ima/ima.h
@@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m
struct ima_template_desc *ima_template_desc_current(void);
int ima_restore_measurement_entry(struct ima_template_entry *entry);
int ima_restore_measurement_list(loff_t bufsize, void *buf);
+int ima_measurements_show(struct seq_file *m, void *v);
unsigned long ima_get_binary_runtime_size(void);
int ima_init_template(void);
diff -puN security/integrity/ima/ima_fs.c~ima-on-soft-reboot-save-the-measurement-list security/integrity/ima/ima_fs.c
--- a/security/integrity/ima/ima_fs.c~ima-on-soft-reboot-save-the-measurement-list
+++ a/security/integrity/ima/ima_fs.c
@@ -116,7 +116,7 @@ void ima_putc(struct seq_file *m, void *
* [eventdata length]
* eventdata[n]=template specific data
*/
-static int ima_measurements_show(struct seq_file *m, void *v)
+int ima_measurements_show(struct seq_file *m, void *v)
{
/* the list never shrinks, so we don't need a lock here */
struct ima_queue_entry *qe = v;
diff -puN security/integrity/ima/ima_kexec.c~ima-on-soft-reboot-save-the-measurement-list security/integrity/ima/ima_kexec.c
--- a/security/integrity/ima/ima_kexec.c~ima-on-soft-reboot-save-the-measurement-list
+++ a/security/integrity/ima/ima_kexec.c
@@ -10,8 +10,125 @@
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/kexec.h>
#include "ima.h"
+#ifdef CONFIG_IMA_KEXEC
+static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
+ unsigned long segment_size)
+{
+ struct ima_queue_entry *qe;
+ struct seq_file file;
+ struct ima_kexec_hdr khdr = {
+ .version = 1, .buffer_size = 0, .count = 0};
+ int ret = 0;
+
+ /* segment size can't change between kexec load and execute */
+ file.buf = vmalloc(segment_size);
+ if (!file.buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ file.size = segment_size;
+ file.read_pos = 0;
+ file.count = sizeof(khdr); /* reserved space */
+
+ list_for_each_entry_rcu(qe, &ima_measurements, later) {
+ if (file.count < file.size) {
+ khdr.count++;
+ ima_measurements_show(&file, qe);
+ } else {
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+ if (ret < 0)
+ goto out;
+
+ /*
+ * fill in reserved space with some buffer details
+ * (eg. version, buffer size, number of measurements)
+ */
+ khdr.buffer_size = file.count;
+ memcpy(file.buf, &khdr, sizeof(khdr));
+ print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
+ 16, 1, file.buf,
+ file.count < 100 ? file.count : 100, true);
+
+ *buffer_size = file.count;
+ *buffer = file.buf;
+out:
+ if (ret == -EINVAL)
+ vfree(file.buf);
+ return ret;
+}
+
+/*
+ * Called during kexec_file_load so that IMA can add a segment to the kexec
+ * image for the measurement list for the next kernel.
+ *
+ * This function assumes that kexec_mutex is held.
+ */
+void ima_add_kexec_buffer(struct kimage *image)
+{
+ struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
+ .buf_min = 0, .buf_max = ULONG_MAX,
+ .top_down = true };
+ unsigned long binary_runtime_size;
+
+ /* use more understandable variable names than defined in kbuf */
+ void *kexec_buffer = NULL;
+ size_t kexec_buffer_size;
+ size_t kexec_segment_size;
+ int ret;
+
+ /*
+ * Reserve an extra half page of memory for additional measurements
+ * added during the kexec load.
+ */
+ binary_runtime_size = ima_get_binary_runtime_size();
+ if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
+ kexec_segment_size = ULONG_MAX;
+ else
+ kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
+ PAGE_SIZE / 2, PAGE_SIZE);
+ if ((kexec_segment_size == ULONG_MAX) ||
+ ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages / 2)) {
+ pr_err("Binary measurement list too large.\n");
+ return;
+ }
+
+ ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
+ kexec_segment_size);
+ if (!kexec_buffer) {
+ pr_err("Not enough memory for the kexec measurement buffer.\n");
+ return;
+ }
+
+ kbuf.buffer = kexec_buffer;
+ kbuf.bufsz = kexec_buffer_size;
+ kbuf.memsz = kexec_segment_size;
+ ret = kexec_add_buffer(&kbuf);
+ if (ret) {
+ pr_err("Error passing over kexec measurement buffer.\n");
+ return;
+ }
+
+ ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
+ if (ret) {
+ pr_err("Error passing over kexec measurement buffer.\n");
+ return;
+ }
+
+ pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
+ kbuf.mem);
+}
+#endif /* IMA_KEXEC */
+
/*
* Restore the measurement list from the previous kernel.
*/
_
Patches currently in -mm which might be from zohar@xxxxxxxxxxxxxxxxxx are
ima-on-soft-reboot-restore-the-measurement-list.patch
ima-permit-duplicate-measurement-list-entries.patch
ima-maintain-memory-size-needed-for-serializing-the-measurement-list.patch
powerpc-ima-send-the-kexec-buffer-to-the-next-kernel.patch
ima-on-soft-reboot-save-the-measurement-list.patch
ima-store-the-builtin-custom-template-definitions-in-a-list.patch
ima-support-restoring-multiple-template-formats.patch
ima-define-a-canonical-binary_runtime_measurements-list-format.patch
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