[PATCH v9 08/23] ima: Move measurement list related variables into ima_namespace

Stefan Berger
2022-01-25T22:47:54Z

From: Stefan Berger <stefanb@linux.ibm.com>

Move measurement list related variables into the ima_namespace. This way
a front-end like securityfs can show the measurement list inside an IMA
namespace.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
security/integrity/ima/ima.h | 5 +++--
security/integrity/ima/ima_fs.c | 6 ++++--
security/integrity/ima/ima_init_ima_ns.c | 5 +++++
security/integrity/ima/ima_kexec.c | 12 ++++++-----
security/integrity/ima/ima_queue.c | 27 +++++++++++-------------
5 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 340a59174670..45706836a77b 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -106,7 +106,6 @@ struct ima_queue_entry {
struct list_head later; /* place in ima_measurements list */
struct ima_template_entry *entry;
};
-extern struct list_head ima_measurements; /* list of all measurements */

/* Some details preceding the binary serialized measurement list */
struct ima_kexec_hdr {
@@ -136,6 +135,8 @@ struct ima_namespace {
struct ima_rule_entry *arch_policy_entry;

struct ima_h_table ima_htable;
+ struct list_head ima_measurements; /* list of all measurements */
+ unsigned long binary_runtime_size; /* used by init_ima_ns */
} __randomize_layout;
extern struct ima_namespace init_ima_ns;

@@ -186,7 +187,7 @@ int ima_restore_measurement_entry(struct ima_namespace *ns,
int ima_restore_measurement_list(struct ima_namespace *ns,
loff_t bufsize, void *buf);
int ima_measurements_show(struct seq_file *m, void *v);
-unsigned long ima_get_binary_runtime_size(void);
+unsigned long ima_get_binary_runtime_size(struct ima_namespace *ns);
int ima_init_template(void);
void ima_init_template_list(void);
int __init ima_init_digests(void);
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 9b4dce57c1a6..b2f088dd8572 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -80,12 +80,13 @@ static const struct file_operations ima_measurements_count_ops = {
/* returns pointer to hlist_node */
static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
{
+ struct ima_namespace *ns = &init_ima_ns;
loff_t l = *pos;
struct ima_queue_entry *qe;

/* we need a lock since pos could point beyond last element */
rcu_read_lock();
- list_for_each_entry_rcu(qe, &ima_measurements, later) {
+ list_for_each_entry_rcu(qe, &ns->ima_measurements, later) {
if (!l--) {
rcu_read_unlock();
return qe;
@@ -97,6 +98,7 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)

static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
{
+ struct ima_namespace *ns = &init_ima_ns;
struct ima_queue_entry *qe = v;

/* lock protects when reading beyond last element
@@ -107,7 +109,7 @@ static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
rcu_read_unlock();
(*pos)++;

- return (&qe->later == &ima_measurements) ? NULL : qe;
+ return (&qe->later == &ns->ima_measurements) ? NULL : qe;
}

static void ima_measurements_stop(struct seq_file *m, void *v)
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index 1945fa8cfc4d..a7477072c587 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -20,6 +20,11 @@ static int ima_init_namespace(struct ima_namespace *ns)
atomic_long_set(&ns->ima_htable.len, 0);
atomic_long_set(&ns->ima_htable.violations, 0);
memset(&ns->ima_htable.queue, 0, sizeof(ns->ima_htable.queue));
+ INIT_LIST_HEAD(&ns->ima_measurements);
+ if (IS_ENABLED(CONFIG_IMA_KEXEC) && ns == &init_ima_ns)
+ ns->binary_runtime_size = 0;
+ else
+ ns->binary_runtime_size = ULONG_MAX;

return 0;
}
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index f3ef8a0df992..e83b18492f46 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -15,7 +15,8 @@
#include "ima.h"

#ifdef CONFIG_IMA_KEXEC
-static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
+static int ima_dump_measurement_list(struct ima_namespace *ns,
+ unsigned long *buffer_size, void **buffer,
unsigned long segment_size)
{
struct ima_queue_entry *qe;
@@ -36,7 +37,7 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,

memset(&khdr, 0, sizeof(khdr));
khdr.version = 1;
- list_for_each_entry_rcu(qe, &ima_measurements, later) {
+ list_for_each_entry_rcu(qe, &ns->ima_measurements, later) {
if (file.count < file.size) {
khdr.count++;
ima_measurements_show(&file, qe);
@@ -84,6 +85,7 @@ 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 };
+ struct ima_namespace *ns = &init_ima_ns;
unsigned long binary_runtime_size;

/* use more understandable variable names than defined in kbuf */
@@ -96,11 +98,11 @@ void ima_add_kexec_buffer(struct kimage *image)
* Reserve an extra half page of memory for additional measurements
* added during the kexec load.
*/
- binary_runtime_size = ima_get_binary_runtime_size();
+ binary_runtime_size = ima_get_binary_runtime_size(ns);
if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
kexec_segment_size = ULONG_MAX;
else
- kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
+ kexec_segment_size = ALIGN(ima_get_binary_runtime_size(ns) +
PAGE_SIZE / 2, PAGE_SIZE);
if ((kexec_segment_size == ULONG_MAX) ||
((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) {
@@ -108,7 +110,7 @@ void ima_add_kexec_buffer(struct kimage *image)
return;
}

- ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
+ ima_dump_measurement_list(ns, &kexec_buffer_size, &kexec_buffer,
kexec_segment_size);
if (!kexec_buffer) {
pr_err("Not enough memory for the kexec measurement buffer.\n");
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 43961d5cd2ef..0355c2b0932c 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -24,13 +24,6 @@
/* pre-allocated array of tpm_digest structures to extend a PCR */
static struct tpm_digest *digests;

-LIST_HEAD(ima_measurements); /* list of all measurements */
-#ifdef CONFIG_IMA_KEXEC
-static unsigned long binary_runtime_size;
-#else
-static unsigned long binary_runtime_size = ULONG_MAX;
-#endif
-
/* mutex protects atomicity of extending measurement list
* and extending the TPM PCR aggregate. Since tpm_extend can take
* long (and the tpm driver uses a mutex), we can't use the spinlock.
@@ -100,7 +93,7 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
qe->entry = entry;

INIT_LIST_HEAD(&qe->later);
- list_add_tail_rcu(&qe->later, &ima_measurements);
+ list_add_tail_rcu(&qe->later, &ns->ima_measurements);

atomic_long_inc(&ns->ima_htable.len);
if (update_htable) {
@@ -110,12 +103,14 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
INIT_HLIST_NODE(&qe->hnext);
}

- if (binary_runtime_size != ULONG_MAX) {
+ if (ns->binary_runtime_size != ULONG_MAX) {
int size;

size = get_binary_runtime_size(entry);
- binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
- binary_runtime_size + size : ULONG_MAX;
+ ns->binary_runtime_size =
+ (ns->binary_runtime_size < ULONG_MAX - size)
+ ? ns->binary_runtime_size + size
+ : ULONG_MAX;
}
return 0;
}
@@ -123,14 +118,16 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
/*
* Return the amount of memory required for serializing the
* entire binary_runtime_measurement list, including the ima_kexec_hdr
- * structure.
+ * structure. Carrying the measurement list across kexec is limited
+ * to init_ima_ns.
*/
-unsigned long ima_get_binary_runtime_size(void)
+unsigned long ima_get_binary_runtime_size(struct ima_namespace *ns)
{
- if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
+ if (ns->binary_runtime_size >=
+ (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
return ULONG_MAX;
else
- return binary_runtime_size + sizeof(struct ima_kexec_hdr);
+ return ns->binary_runtime_size + sizeof(struct ima_kexec_hdr);
}

static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
--
2.31.1