[PATCH 17/17] prmem: ima: turn the measurements list write rare

From: Igor Stoppa
Date: Tue Oct 23 2018 - 17:36:28 EST

The measurement list is moved to write rare memory, including
related data structures.

Various boilerplate linux data structures and related functions are
replaced by their write-rare counterpart.

Signed-off-by: Igor Stoppa <igor.stoppa@xxxxxxxxxx>
CC: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
CC: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
CC: James Morris <jmorris@xxxxxxxxx>
CC: "Serge E. Hallyn" <serge@xxxxxxxxxx>
CC: linux-integrity@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
security/integrity/ima/ima.h | 18 ++++++++------
security/integrity/ima/ima_api.c | 29 +++++++++++++----------
security/integrity/ima/ima_fs.c | 12 +++++-----
security/integrity/ima/ima_main.c | 6 +++++
security/integrity/ima/ima_queue.c | 28 +++++++++++++---------
security/integrity/ima/ima_template.c | 14 ++++++-----
security/integrity/ima/ima_template_lib.c | 14 +++++++----
7 files changed, 74 insertions(+), 47 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 67db9d9454ca..5f5959753bf5 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -24,6 +24,8 @@
#include <linux/hash.h>
#include <linux/tpm.h>
#include <linux/audit.h>
+#include <linux/prlist.h>
+#include <linux/pratomic-long.h>
#include <crypto/hash_info.h>

#include "../integrity.h"
@@ -84,7 +86,7 @@ struct ima_template_field {

/* IMA template descriptor definition */
struct ima_template_desc {
- struct list_head list;
+ union prlist_head list;
char *name;
char *fmt;
int num_fields;
@@ -100,11 +102,13 @@ struct ima_template_entry {
};

struct ima_queue_entry {
- struct hlist_node hnext; /* place in hash collision list */
- struct list_head later; /* place in ima_measurements list */
+ union prhlist_node hnext; /* place in hash collision list */
+ union prlist_head later; /* place in ima_measurements list */
struct ima_template_entry *entry;
};
-extern struct list_head ima_measurements; /* list of all measurements */
+
+/* list of all measurements */
+extern union prlist_head ima_measurements __wr_after_init;

/* Some details preceding the binary serialized measurement list */
struct ima_kexec_hdr {
@@ -160,9 +164,9 @@ void ima_init_template_list(void);
extern spinlock_t ima_queue_lock;

struct ima_h_table {
- atomic_long_t len; /* number of stored measurements in the list */
- atomic_long_t violations;
- struct hlist_head queue[IMA_MEASURE_HTABLE_SIZE];
+ struct pratomic_long_t len; /* # of measurements in the list */
+ struct pratomic_long_t violations;
+ union prhlist_head queue[IMA_MEASURE_HTABLE_SIZE];
};
extern struct ima_h_table ima_htable;

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index a02c5acfd403..4fc28c2478b0 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -19,9 +19,12 @@
#include <linux/xattr.h>
#include <linux/evm.h>
#include <linux/iversion.h>
+#include <linux/prmemextra.h>
+#include <linux/pratomic-long.h>

#include "ima.h"

+extern struct pmalloc_pool ima_pool;
/*
* ima_free_template_entry - free an existing template entry
*/
@@ -29,10 +32,10 @@ void ima_free_template_entry(struct ima_template_entry *entry)
{
int i;

- for (i = 0; i < entry->template_desc->num_fields; i++)
- kfree(entry->template_data[i].data);
+// for (i = 0; i < entry->template_desc->num_fields; i++)
+// kfree(entry->template_data[i].data);

- kfree(entry);
+// kfree(entry);
}

/*
@@ -44,12 +47,13 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
struct ima_template_desc *template_desc = ima_template_desc_current();
int i, result = 0;

- *entry = kzalloc(sizeof(**entry) + template_desc->num_fields *
- sizeof(struct ima_field_data), GFP_NOFS);
+ *entry = pzalloc(&ima_pool,
+ sizeof(**entry) + template_desc->num_fields *
+ sizeof(struct ima_field_data));
if (!*entry)
return -ENOMEM;

- (*entry)->template_desc = template_desc;
+ wr_ptr(&((*entry)->template_desc), template_desc);
for (i = 0; i < template_desc->num_fields; i++) {
struct ima_template_field *field = template_desc->fields[i];
u32 len;
@@ -59,9 +63,10 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
if (result != 0)
goto out;

- len = (*entry)->template_data[i].len;
- (*entry)->template_data_len += sizeof(len);
- (*entry)->template_data_len += len;
+ len = (*entry)->template_data_len + sizeof(len) +
+ (*entry)->template_data[i].len;
+ wr_memcpy(&(*entry)->template_data_len, &len,
+ sizeof(len));
}
return 0;
out:
@@ -113,9 +118,9 @@ int ima_store_template(struct ima_template_entry *entry,
audit_cause, result, 0);
return result;
}
- memcpy(entry->digest, hash.hdr.digest, hash.hdr.length);
+ wr_memcpy(entry->digest, hash.hdr.digest, hash.hdr.length);
}
- entry->pcr = pcr;
+ wr_int(&entry->pcr, pcr);
result = ima_add_template_entry(entry, violation, op, inode, filename);
return result;
}
@@ -139,7 +144,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
int result;

/* can overflow, only indicator */
- atomic_long_inc(&ima_htable.violations);
+ pratomic_long_inc(&ima_htable.violations);

result = ima_alloc_init_template(&event_data, &entry);
if (result < 0) {
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index ae9d5c766a3c..ab20da1161c7 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -57,7 +57,8 @@ static ssize_t ima_show_htable_violations(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
- return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
+ return ima_show_htable_value(buf, count, ppos,
+ &ima_htable.violations.l);
}

static const struct file_operations ima_htable_violations_ops = {
@@ -69,8 +70,7 @@ static ssize_t ima_show_measurements_count(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
- return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
-
+ return ima_show_htable_value(buf, count, ppos, &ima_htable.len.l);
}

static const struct file_operations ima_measurements_count_ops = {
@@ -86,7 +86,7 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)

/* 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, &ima_measurements.list, later.list) {
if (!l--) {
rcu_read_unlock();
return qe;
@@ -303,7 +303,7 @@ static ssize_t ima_read_policy(char *path)
size -= rc;
}

- vfree(data);
+// vfree(data);
if (rc < 0)
return rc;
else if (size)
@@ -350,7 +350,7 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
}
mutex_unlock(&ima_write_mutex);
out_free:
- kfree(data);
+// kfree(data);
out:
if (result < 0)
valid_policy = 0;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2d31921fbda4..d52e59006781 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -29,6 +29,7 @@
#include <linux/ima.h>
#include <linux/iversion.h>
#include <linux/fs.h>
+#include <linux/prlist.h>

#include "ima.h"

@@ -536,10 +537,15 @@ int ima_load_data(enum kernel_load_data_id id)
return 0;
}

+struct pmalloc_pool ima_pool;
+
+#define IMA_POOL_ALLOC_CHUNK (16 * PAGE_SIZE)
static int __init init_ima(void)
{
int error;

+ pmalloc_init_custom_pool(&ima_pool, IMA_POOL_ALLOC_CHUNK, 3,
+ PMALLOC_MODE_START_WR);
ima_init_template_list();
hash_setup(CONFIG_IMA_DEFAULT_HASH);
error = ima_init();
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index b186819bd5aa..444c47b745d8 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -24,11 +24,14 @@
#include <linux/module.h>
#include <linux/rculist.h>
#include <linux/slab.h>
+#include <linux/prmemextra.h>
+#include <linux/prlist.h>
+#include <linux/pratomic-long.h>
#include "ima.h"

#define AUDIT_CAUSE_LEN_MAX 32

-LIST_HEAD(ima_measurements); /* list of all measurements */
+PRLIST_HEAD(ima_measurements); /* list of all measurements */
#ifdef CONFIG_IMA_KEXEC
static unsigned long binary_runtime_size;
#else
@@ -36,9 +39,9 @@ static unsigned long binary_runtime_size = ULONG_MAX;
#endif

/* key: inode (before secure-hashing a file) */
-struct ima_h_table ima_htable = {
- .len = ATOMIC_LONG_INIT(0),
- .violations = ATOMIC_LONG_INIT(0),
+struct ima_h_table ima_htable __wr_after_init = {
+ .len = PRATOMIC_LONG_INIT(0),
+ .violations = PRATOMIC_LONG_INIT(0),
.queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
};

@@ -58,7 +61,7 @@ static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,

key = ima_hash_key(digest_value);
rcu_read_lock();
- hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
+ hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext.node) {
rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
if ((rc == 0) && (qe->entry->pcr == pcr)) {
ret = qe;
@@ -87,6 +90,8 @@ static int get_binary_runtime_size(struct ima_template_entry *entry)
return size;
}

+extern struct pmalloc_pool ima_pool;
+
/* ima_add_template_entry helper function:
* - Add template entry to the measurement list and hash table, for
* all entries except those carried across kexec.
@@ -99,20 +104,21 @@ static int ima_add_digest_entry(struct ima_template_entry *entry,
struct ima_queue_entry *qe;
unsigned int key;

- qe = kmalloc(sizeof(*qe), GFP_KERNEL);
+ qe = pmalloc(&ima_pool, sizeof(*qe));
if (qe == NULL) {
pr_err("OUT OF MEMORY ERROR creating queue entry\n");
return -ENOMEM;
}
- qe->entry = entry;
+ wr_ptr(&qe->entry, entry);
+ INIT_PRLIST_HEAD(&qe->later);
+ prlist_add_tail_rcu(&qe->later, &ima_measurements);
+

- INIT_LIST_HEAD(&qe->later);
- list_add_tail_rcu(&qe->later, &ima_measurements);
+ pratomic_long_inc(&ima_htable.len);

- atomic_long_inc(&ima_htable.len);
if (update_htable) {
key = ima_hash_key(entry->digest);
- hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
+ prhlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
}

if (binary_runtime_size != ULONG_MAX) {
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 30db39b23804..40ae57a17d89 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -22,14 +22,15 @@
enum header_fields { HDR_PCR, HDR_DIGEST, HDR_TEMPLATE_NAME,
HDR_TEMPLATE_DATA, HDR__LAST };

-static struct ima_template_desc builtin_templates[] = {
+static struct ima_template_desc builtin_templates[] __wr_after_init = {
{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
{.name = "ima-ng", .fmt = "d-ng|n-ng"},
{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
{.name = "", .fmt = ""}, /* placeholder for a custom format */
};

-static LIST_HEAD(defined_templates);
+static PRLIST_HEAD(defined_templates);
+
static DEFINE_SPINLOCK(template_list);

static struct ima_template_field supported_fields[] = {
@@ -114,7 +115,8 @@ static struct ima_template_desc *lookup_template_desc(const char *name)
int found = 0;

rcu_read_lock();
- list_for_each_entry_rcu(template_desc, &defined_templates, list) {
+ list_for_each_entry_rcu(template_desc, &defined_templates.list,
+ list.list) {
if ((strcmp(template_desc->name, name) == 0) ||
(strcmp(template_desc->fmt, name) == 0)) {
found = 1;
@@ -207,12 +209,12 @@ void ima_init_template_list(void)
{
int i;

- if (!list_empty(&defined_templates))
+ if (!list_empty(&defined_templates.list))
return;

spin_lock(&template_list);
for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
- list_add_tail_rcu(&builtin_templates[i].list,
+ prlist_add_tail_rcu(&builtin_templates[i].list,
&defined_templates);
}
spin_unlock(&template_list);
@@ -266,7 +268,7 @@ static struct ima_template_desc *restore_template_fmt(char *template_name)
goto out;

spin_lock(&template_list);
- list_add_tail_rcu(&template_desc->list, &defined_templates);
+ prlist_add_tail_rcu(&template_desc->list, &defined_templates);
spin_unlock(&template_list);
out:
return template_desc;
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 43752002c222..a6d10eabf0e5 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -15,8 +15,12 @@

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <linux/printk.h>
+#include <linux/prmemextra.h>
#include "ima_template_lib.h"

+extern struct pmalloc_pool ima_pool;
+
static bool ima_template_hash_algo_allowed(u8 algo)
{
if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
@@ -42,11 +46,11 @@ static int ima_write_template_field_data(const void *data, const u32 datalen,
if (datafmt == DATA_FMT_STRING)
buflen = datalen + 1;

- buf = kzalloc(buflen, GFP_KERNEL);
+ buf = pzalloc(&ima_pool, buflen);
if (!buf)
return -ENOMEM;

- memcpy(buf, data, datalen);
+ wr_memcpy(buf, data, datalen);

/*
* Replace all space characters with underscore for event names and
@@ -58,11 +62,11 @@ static int ima_write_template_field_data(const void *data, const u32 datalen,
if (datafmt == DATA_FMT_STRING) {
for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
if (*buf_ptr == ' ')
- *buf_ptr = '_';
+ wr_char(buf_ptr, '_');
}

- field_data->data = buf;
- field_data->len = buflen;
+ wr_ptr(&field_data->data, buf);
+ wr_memcpy(&field_data->len, &buflen, sizeof(buflen));
return 0;
}

--
2.17.1