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
serializes the IMA measurement list in the binary_runtime_measurements
format.
Signed-off-by: Mimi Zohar <zo...@linux.vnet.ibm.com>
---
security/integrity/ima/ima.h | 1 +
security/integrity/ima/ima_fs.c | 2 +-
security/integrity/ima/ima_kexec.c | 51 ++++++++++++++++++++++++++++++++++++++
3 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 222668f..f972296 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -132,6 +132,7 @@ struct ima_template_desc *ima_template_desc_current(void);
void ima_load_kexec_buffer(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 --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index c07a384..66e5dd5 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -116,7 +116,7 @@ void ima_putc(struct seq_file *m, void *data, int datalen)
* [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 --git a/security/integrity/ima/ima_kexec.c
b/security/integrity/ima/ima_kexec.c
index 6a046ad..e77ca9d 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -23,6 +23,57 @@
#include "ima.h"
+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;
+}
+
/*
* Restore the measurement list from the previous kernel.
*/
--
2.1.0
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