[PATCH v4 4/9] ima: serialize the binary_runtime_measurements
From: Mimi Zohar <hidden>
Date: 2016-09-15 11:28:03
Also in:
kexec, lkml
Subsystem:
extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
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 <redacted> --- 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 f9cd08e..634d140 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h@@ -133,6 +133,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, u32 size); 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 --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