[PATCH v9 0/3] mm: security: ro protection for dynamic data

[PATCH v9 0/3] mm: security: ro protection for dynamic data

[Igor Stoppa]

Hi,
please consider this patch-set for inclusion.

This patch-set introduces the possibility of protecting memory that has
been allocated dynamically.

The memory is managed in pools: when a memory pool is turned into R/O,
all the memory that is part of it, will become R/O.

A R/O pool can be destroyed, to recover its memory, but it cannot be
turned back into R/W mode.

This is intentional. This feature is meant for data that doesn't need
further modifications after initialization.

However the data might need to be released, as part of module unloading.
To do this, the memory must first be freed, then the pool can be destroyed.

An example is provided, showing how to turn into a boot-time option the
writable state of the security hooks.
Prior to this patch, it was a compile-time option.

This is made possible, thanks to Tetsuo Handa's rework of the hooks
structure (included in the patchset).

Changes since the v8 version:
- do not abuse devres, but manage the pools in a normal list
- added one sysfs attribute, showing the number of chnks in each pool

Question still open:
- should it be possibile to unprotect a pool for rewrite?

The only cases found for this topic are:
- protecting the LSM header structure between creation and insertion of a
  security module that was not built as part of the kernel
  (but the module can protect the headers after it has loaded)

- unloading SELinux from RedHat, if the system has booted, but no policy
  has been loaded yet - this feature is going away, according to Casey.

Regarding the last point, there was a comment from Christoph Hellwig,
for which I asked for clarifications, but it's still pending:

https://marc.info/?l=linux-mm&m=149863848120692&w=2


Notes:

- The patch is larg-ish, but I was not sure what criteria to use for
  splitting it. If it helps the reviewing, please do let me know how I
  should split it and I will comply.
- I had to rebase Tetsuo Handa's patch because it didn't apply cleanly
  anymore, I would appreciate an ACK to that or a revised patch, whatever 
  comes easier.


Igor Stoppa (2):
  Protectable memory support
  Make LSM Writable Hooks a command line option

Tetsuo Handa (1):
  LSM: Convert security_hook_heads into explicit array of struct
    list_head

 arch/Kconfig                   |   1 +
 include/linux/lsm_hooks.h      | 420 ++++++++++++++++++++---------------------
 include/linux/page-flags.h     |   2 +
 include/linux/pmalloc.h        | 127 +++++++++++++
 include/trace/events/mmflags.h |   1 +
 lib/Kconfig                    |   1 +
 mm/Makefile                    |   1 +
 mm/pmalloc.c                   | 356 ++++++++++++++++++++++++++++++++++
 mm/usercopy.c                  |  24 ++-
 security/security.c            |  49 +++--
 10 files changed, 748 insertions(+), 234 deletions(-)
 create mode 100644 include/linux/pmalloc.h
 create mode 100644 mm/pmalloc.c

-- 
2.9.3

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[PATCH 1/3] Protectable memory support

[Igor Stoppa]

The MMU available in many systems running Linux can often provide R/O
protection to the memory pages it handles.

However, the MMU-based protection works efficiently only when said pages
contain exclusively data that will not need further modifications.

Statically allocated variables can be segregated into a dedicated
section, but this does not sit very well with dynamically allocated ones.

Dynamic allocation does not provide, currently, any means for grouping
variables in memory pages that would contain exclusively data suitable
for conversion to read only access mode.

The allocator here provided (pmalloc - protectable memory allocator)
introduces the concept of pools of protectable memory.

A module can request a pool and then refer any allocation request to the
pool handler it has received.

Once all the chunks of memory associated to a specific pool are
initialized, the pool can be protected.

After this point, the pool can only be destroyed (it is up to the module
to avoid any further references to the memory from the pool, after
the destruction is invoked).

The latter case is mainly meant for releasing memory, when a module is
unloaded.

A module can have as many pools as needed, for example to support the
protection of data that is initialized in sufficiently distinct phases.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
---
 arch/Kconfig                   |   1 +
 include/linux/page-flags.h     |   2 +
 include/linux/pmalloc.h        | 127 +++++++++++++++
 include/trace/events/mmflags.h |   1 +
 lib/Kconfig                    |   1 +
 mm/Makefile                    |   1 +
 mm/pmalloc.c                   | 356 +++++++++++++++++++++++++++++++++++++++++
 mm/usercopy.c                  |  24 +--
 8 files changed, 504 insertions(+), 9 deletions(-)
 create mode 100644 include/linux/pmalloc.h
 create mode 100644 mm/pmalloc.c

diff --git a/arch/Kconfig b/arch/Kconfig
index 6c00e5b..9d16b51 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -228,6 +228,7 @@ config GENERIC_IDLE_POLL_SETUP
 
 # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
 config ARCH_HAS_SET_MEMORY
+	select GENERIC_ALLOCATOR
 	bool
 
 # Select if arch init_task initializer is different to init/init_task.c
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 6b5818d..acc0723 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -81,6 +81,7 @@ enum pageflags {
 	PG_active,
 	PG_waiters,		/* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
 	PG_slab,
+	PG_pmalloc,
 	PG_owner_priv_1,	/* Owner use. If pagecache, fs may use*/
 	PG_arch_1,
 	PG_reserved,
@@ -274,6 +275,7 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
 	TESTCLEARFLAG(Active, active, PF_HEAD)
 __PAGEFLAG(Slab, slab, PF_NO_TAIL)
 __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
+__PAGEFLAG(Pmalloc, pmalloc, PF_NO_TAIL)
 PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
 
 /* Xen */
diff --git a/include/linux/pmalloc.h b/include/linux/pmalloc.h
new file mode 100644
index 0000000..a374e5e
--- /dev/null
+++ b/include/linux/pmalloc.h
@@ -0,0 +1,127 @@
+/*
+ * pmalloc.h: Header for Protectable Memory Allocator
+ *
+ * (C) Copyright 2017 Huawei Technologies Co. Ltd.
+ * Author: Igor Stoppa <igor.stoppa@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#ifndef _PMALLOC_H
+#define _PMALLOC_H
+#include <linux/genalloc.h>
+
+#define PMALLOC_DEFAULT_ALLOC_ORDER (-1)
+
+/*
+ * Library for dynamic allocation of pools of memory that can be,
+ * after initialization, marked as read-only.
+ *
+ * This is intended to complement __read_only_after_init, for those cases
+ * where either it is not possible to know the initialization value before
+ * init is completed, or the amount of data is variable and can be
+ * determined only at runtime.
+ *
+ * ***WARNING***
+ * The user of the API is expected to synchronize:
+ * 1) allocation
+ * 2) writes to the allocated memory
+ * 3) write protection of the pool
+ * 4) freeing of the allocated memory
+ * 5) destruction of the pool
+ *
+ * For a non threaded scenario, this type of locking is not even required.
+ *
+ * Even if the library were to provided support for the locking, point 2)
+ * would still depend on the user to remember taking the lock.
+ *
+ */
+
+
+/**
+ * pmalloc_create_pool - create a new protectable memory pool -
+ * @name: the name of the pool, must be unique
+ * @min_alloc_order: log2 of the minimum allocation size obtainable
+ *                   from the pool
+ *
+ * Creates a new (empty) memory pool for allocation of protectable
+ * memory. Memory will be allocated upon request (through pmalloc).
+ *
+ * Returns a pointer to the new pool, upon succes, otherwise a NULL.
+ */
+struct gen_pool *pmalloc_create_pool(const char *name,
+					 int min_alloc_order);
+
+
+/**
+ * pmalloc - allocate protectable memory from a pool
+ * @pool: handler to the pool to be used for memory allocation
+ * @size: amount of memory (in bytes) requested
+ *
+ * Allocates memory from an unprotected pool. If the pool doesn't have
+ * enough memory, an attempt is made to add to the pool a new chunk of
+ * memory (multiple of PAGE_SIZE) that can fit the new request.
+ *
+ * Returns the pointer to the memory requested, upon success,
+ * NULL otherwise (either no memory availabel or pool RO).
+ *
+ */
+void *pmalloc(struct gen_pool *pool, size_t size);
+
+
+
+/**
+ * pmalloc_free - release memory previously obtained through pmalloc
+ * @pool: the pool providing the memory
+ * @addr: the memory address obtained from pmalloc
+ * @size: the same amount of memory that was requested from pmalloc
+ *
+ * Releases the memory that was previously accounted for as in use.
+ * It works also on pocked pools, but the memory released is simply
+ * removed from the refcount of memory in use. It cannot be re-used.
+ */
+static __always_inline
+void pmalloc_free(struct gen_pool *pool, void *addr, size_t size)
+{
+	gen_pool_free(pool, (unsigned long)addr, size);
+}
+
+
+
+/**
+ * pmalloc_protect_pool - turn a RW pool into RO
+ * @pool: the pool to protect
+ *
+ * Write protects all the memory chunks assigned to the pool.
+ * This prevents further allocation.
+ *
+ * Returns 0 upon success, -EINVAL in abnormal cases.
+ */
+int pmalloc_protect_pool(struct gen_pool *pool);
+
+
+
+/**
+ * pmalloc_pool_protected - check if the pool is protected
+ * @pool: the pool to test
+ *
+ * Returns true if the pool is either protected or missing. False otherwise.
+ */
+bool pmalloc_pool_protected(struct gen_pool *pool);
+
+
+
+/**
+ * pmalloc_destroy_pool - destroys a pool and all the associated memory
+ * @pool: the pool to destroy
+ *
+ * All the memory that was allocated through pmalloc must first be freed
+ * with pmalloc_free. Falire to do so will BUG().
+ *
+ * Returns 0 upon success, -EINVAL in abnormal cases.
+ */
+int pmalloc_destroy_pool(struct gen_pool *pool);
+#endif
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 304ff94..41d1587 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -91,6 +91,7 @@
 	{1UL << PG_lru,			"lru"		},		\
 	{1UL << PG_active,		"active"	},		\
 	{1UL << PG_slab,		"slab"		},		\
+	{1UL << PG_pmalloc,		"pmalloc"	},		\
 	{1UL << PG_owner_priv_1,	"owner_priv_1"	},		\
 	{1UL << PG_arch_1,		"arch_1"	},		\
 	{1UL << PG_reserved,		"reserved"	},		\
diff --git a/lib/Kconfig b/lib/Kconfig
index 0c8b78a..3e3b8f6 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -270,6 +270,7 @@ config DECOMPRESS_LZ4
 # Generic allocator support is selected if needed
 #
 config GENERIC_ALLOCATOR
+	depends on ARCH_HAS_SET_MEMORY
 	bool
 
 #
diff --git a/mm/Makefile b/mm/Makefile
index 026f6a8..b47dcf8 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_SPARSEMEM)	+= sparse.o
 obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
 obj-$(CONFIG_SLOB) += slob.o
 obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
+obj-$(CONFIG_ARCH_HAS_SET_MEMORY) += pmalloc.o
 obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += page_poison.o
 obj-$(CONFIG_SLAB) += slab.o
diff --git a/mm/pmalloc.c b/mm/pmalloc.c
new file mode 100644
index 0000000..8a21fe9
--- /dev/null
+++ b/mm/pmalloc.c
@@ -0,0 +1,356 @@
+/*
+ * pmalloc.c: Protectable Memory Allocator
+ *
+ * (C) Copyright 2017 Huawei Technologies Co. Ltd.
+ * Author: Igor Stoppa <igor.stoppa@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/printk.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/genalloc.h>
+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/atomic.h>
+#include <linux/rculist.h>
+#include <asm/set_memory.h>
+#include <asm/page.h>
+
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
+
+static LIST_HEAD(tmp_list);
+
+/**
+ * pmalloc_data contains the data specific to a pmalloc pool,
+ * in a format compatible with the design of gen_alloc.
+ * Some of the fields are used for exposing the corresponding parameter
+ * to userspace, through sysfs.
+ */
+struct pmalloc_data {
+	struct gen_pool *pool;  /* Link back to the associated pool. */
+	bool protected;     /* Status of the pool: RO or RW. */
+	struct kobj_attribute attr_protected; /* Sysfs attribute. */
+	struct kobj_attribute attr_avail;     /* Sysfs attribute. */
+	struct kobj_attribute attr_size;      /* Sysfs attribute. */
+	struct kobj_attribute attr_chunks;    /* Sysfs attribute. */
+	struct kobject *pool_kobject;
+	struct list_head node; /* list of pools */
+	struct mutex mutex;
+};
+
+static LIST_HEAD(pmalloc_final_list);
+static LIST_HEAD(pmalloc_tmp_list);
+static struct list_head *pmalloc_list = &pmalloc_tmp_list;
+static DEFINE_MUTEX(pmalloc_mutex);
+static struct kobject *pmalloc_kobject;
+
+static ssize_t __pmalloc_pool_show_protected(struct kobject *dev,
+					     struct kobj_attribute *attr,
+					     char *buf)
+{
+	struct pmalloc_data *data;
+
+	data = container_of(attr, struct pmalloc_data, attr_protected);
+	if (data->protected)
+		return sprintf(buf, "protected\n");
+	else
+		return sprintf(buf, "unprotected\n");
+}
+
+static ssize_t __pmalloc_pool_show_avail(struct kobject *dev,
+					 struct kobj_attribute *attr,
+					 char *buf)
+{
+	struct pmalloc_data *data;
+
+	data = container_of(attr, struct pmalloc_data, attr_avail);
+	return sprintf(buf, "%lu\n", gen_pool_avail(data->pool));
+}
+
+static ssize_t __pmalloc_pool_show_size(struct kobject *dev,
+					struct kobj_attribute *attr,
+					char *buf)
+{
+	struct pmalloc_data *data;
+
+	data = container_of(attr, struct pmalloc_data, attr_size);
+	return sprintf(buf, "%lu\n", gen_pool_size(data->pool));
+}
+
+static void __pool_chunk_number(struct gen_pool *pool,
+				struct gen_pool_chunk *chunk, void *data)
+{
+	if (!data)
+		return;
+	*(unsigned long *)data += 1;
+}
+
+static ssize_t __pmalloc_pool_show_chunks(struct kobject *dev,
+					  struct kobj_attribute *attr,
+					  char *buf)
+{
+	struct pmalloc_data *data;
+	unsigned long chunks_num = 0;
+
+	data = container_of(attr, struct pmalloc_data, attr_chunks);
+	gen_pool_for_each_chunk(data->pool, __pool_chunk_number, &chunks_num);
+	return sprintf(buf, "%lu\n", chunks_num);
+}
+
+/**
+ * Exposes the pool and its attributes through sysfs.
+ */
+static void __pmalloc_connect(struct pmalloc_data *data)
+{
+	data->pool_kobject = kobject_create_and_add(data->pool->name,
+						    pmalloc_kobject);
+	sysfs_create_file(data->pool_kobject, &data->attr_protected.attr);
+	sysfs_create_file(data->pool_kobject, &data->attr_avail.attr);
+	sysfs_create_file(data->pool_kobject, &data->attr_size.attr);
+	sysfs_create_file(data->pool_kobject, &data->attr_chunks.attr);
+}
+
+/**
+ * Removes the pool and its attributes from sysfs.
+ */
+static void __pmalloc_disconnect(struct pmalloc_data *data)
+{
+	sysfs_remove_file(data->pool_kobject, &data->attr_protected.attr);
+	sysfs_remove_file(data->pool_kobject, &data->attr_avail.attr);
+	sysfs_remove_file(data->pool_kobject, &data->attr_size.attr);
+	sysfs_remove_file(data->pool_kobject, &data->attr_chunks.attr);
+	kobject_put(data->pool_kobject);
+}
+
+/**
+ * Declares an attribute of the pool.
+ */
+
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define do_lock_dep(data, attr_name) \
+	(data->attr_##attr_name.attr.ignore_lockdep = 1)
+#else
+#define do_lock_dep(data, attr_name) do {} while (0)
+#endif
+
+#define __pmalloc_attr_init(data, attr_name) \
+do { \
+	data->attr_##attr_name.attr.name = #attr_name; \
+	data->attr_##attr_name.attr.mode = VERIFY_OCTAL_PERMISSIONS(0444); \
+	data->attr_##attr_name.show = __pmalloc_pool_show_##attr_name; \
+	do_lock_dep(data, attr_name); \
+} while (0)
+
+struct gen_pool *pmalloc_create_pool(const char *name, int min_alloc_order)
+{
+	struct gen_pool *pool;
+	const char *pool_name;
+	struct pmalloc_data *data;
+
+	if (!name)
+		return NULL;
+	pool_name = kstrdup(name, GFP_KERNEL);
+	if (!pool_name)
+		return NULL;
+	data = kzalloc(sizeof(struct pmalloc_data), GFP_KERNEL);
+	if (!data)
+		return NULL;
+	if (min_alloc_order < 0)
+		min_alloc_order = ilog2(sizeof(unsigned long));
+	pool = gen_pool_create(min_alloc_order, NUMA_NO_NODE);
+	if (!pool) {
+		kfree(pool_name);
+		kfree(data);
+		return NULL;
+	}
+	data->protected = false;
+	data->pool = pool;
+	mutex_init(&data->mutex);
+	__pmalloc_attr_init(data, protected);
+	__pmalloc_attr_init(data, avail);
+	__pmalloc_attr_init(data, size);
+	__pmalloc_attr_init(data, chunks);
+	pool->data = data;
+	pool->name = pool_name;
+	mutex_lock(&pmalloc_mutex);
+	list_add(&data->node, &pmalloc_tmp_list);
+	if (pmalloc_list == &pmalloc_final_list)
+		__pmalloc_connect(data);
+	mutex_unlock(&pmalloc_mutex);
+	return pool;
+}
+
+
+/**
+ * To support hardened usercopy, tag/untag pages supplied by pmalloc.
+ * Pages are tagged when added to a pool and untagged when removed
+ * from said pool.
+ */
+#define PMALLOC_TAG_PAGE true
+#define PMALLOC_UNTAG_PAGE false
+static inline
+int __pmalloc_tag_pages(void *base, const size_t size, const bool set_tag)
+{
+	void *end = base + size - 1;
+
+	do {
+		struct page *page;
+
+		if (!is_vmalloc_addr(base))
+			return -EINVAL;
+		page = vmalloc_to_page(base);
+		if (set_tag)
+			__SetPagePmalloc(page);
+		else
+			__ClearPagePmalloc(page);
+		base += PAGE_SIZE;
+	} while ((PAGE_MASK & (unsigned long)base) <=
+		 (PAGE_MASK & (unsigned long)end));
+	return 0;
+}
+
+
+static void __page_untag(struct gen_pool *pool,
+			 struct gen_pool_chunk *chunk, void *data)
+{
+	__pmalloc_tag_pages((void *)chunk->start_addr,
+			    chunk->end_addr - chunk->start_addr + 1,
+			    PMALLOC_UNTAG_PAGE);
+}
+
+void *pmalloc(struct gen_pool *pool, size_t size)
+{
+	void *retval, *chunk;
+	size_t chunk_size;
+
+	if (!size || !pool || ((struct pmalloc_data *)pool->data)->protected)
+		return NULL;
+	retval = (void *)gen_pool_alloc(pool, size);
+	if (retval)
+		return retval;
+	chunk_size = roundup(size, PAGE_SIZE);
+	chunk = vmalloc(chunk_size);
+	if (!chunk)
+		return NULL;
+	__pmalloc_tag_pages(chunk, size, PMALLOC_TAG_PAGE);
+	/* Locking is already done inside gen_pool_add_virt */
+	BUG_ON(gen_pool_add_virt(pool, (unsigned long)chunk,
+				(phys_addr_t)NULL, chunk_size, NUMA_NO_NODE));
+	return (void *)gen_pool_alloc(pool, size);
+}
+
+static void __page_protection(struct gen_pool *pool,
+			      struct gen_pool_chunk *chunk, void *data)
+{
+	unsigned long pages;
+
+	if (!data)
+		return;
+	pages = roundup(chunk->end_addr - chunk->start_addr + 1,
+			PAGE_SIZE) / PAGE_SIZE;
+	if (*(bool *)data)
+		set_memory_ro(chunk->start_addr, pages);
+	else
+		set_memory_rw(chunk->start_addr, pages);
+}
+
+static int __pmalloc_pool_protection(struct gen_pool *pool, bool protection)
+{
+	struct pmalloc_data *data;
+	struct gen_pool_chunk *chunk;
+
+	if (!pool)
+		return -EINVAL;
+	data = (struct pmalloc_data *)pool->data;
+	mutex_lock(&data->mutex);
+	BUG_ON(data->protected == protection);
+	data->protected = protection;
+	list_for_each_entry(chunk, &(pool)->chunks, next_chunk)
+		__page_protection(pool, chunk, &protection);
+	mutex_unlock(&data->mutex);
+	return 0;
+}
+
+int pmalloc_protect_pool(struct gen_pool *pool)
+{
+	return __pmalloc_pool_protection(pool, true);
+}
+
+
+bool pmalloc_pool_protected(struct gen_pool *pool)
+{
+	if (!pool)
+		return true;
+	return ((struct pmalloc_data *)pool->data)->protected;
+}
+
+
+int pmalloc_destroy_pool(struct gen_pool *pool)
+{
+	struct pmalloc_data *data;
+
+	if (!pool)
+		return -EINVAL;
+	data = (struct pmalloc_data *)pool->data;
+	mutex_lock(&data->mutex);
+	list_del(&data->node);
+	mutex_unlock(&data->mutex);
+	gen_pool_for_each_chunk(pool, __page_untag, NULL);
+	__pmalloc_disconnect(data);
+	__pmalloc_pool_protection(pool, false);
+	gen_pool_destroy(pool);
+	kfree(data);
+	return 0;
+}
+
+static const char msg[] = "Not a valid Pmalloc object.";
+const char *__pmalloc_check_object(const void *ptr, unsigned long n)
+{
+	unsigned long p;
+
+	p = (unsigned long)ptr;
+	n = p + n - 1;
+	for (; (PAGE_MASK & p) <= (PAGE_MASK & n); p += PAGE_SIZE) {
+		struct page *page;
+
+		if (!is_vmalloc_addr((void *)p))
+			return msg;
+		page = vmalloc_to_page((void *)p);
+		if (!(page && PagePmalloc(page)))
+			return msg;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(__pmalloc_check_object);
+
+
+/**
+ * When the sysfs is ready to receive registrations, connect all the
+ * pools previously created. Also enable further pools to be connected
+ * right away.
+ */
+static int __init pmalloc_late_init(void)
+{
+	struct pmalloc_data *data, *n;
+
+	pmalloc_kobject = kobject_create_and_add("pmalloc", kernel_kobj);
+	mutex_lock(&pmalloc_mutex);
+	pmalloc_list = &pmalloc_final_list;
+	list_for_each_entry_safe(data, n, &pmalloc_tmp_list, node) {
+		list_move(&data->node, &pmalloc_final_list);
+		__pmalloc_connect(data);
+	}
+	mutex_unlock(&pmalloc_mutex);
+	return 0;
+}
+late_initcall(pmalloc_late_init);
diff --git a/mm/usercopy.c b/mm/usercopy.c
index a9852b2..29bb691 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -195,22 +195,28 @@ static inline const char *check_page_span(const void *ptr, unsigned long n,
 	return NULL;
 }
 
+extern const char *__pmalloc_check_object(const void *ptr, unsigned long n);
+
 static inline const char *check_heap_object(const void *ptr, unsigned long n,
 					    bool to_user)
 {
 	struct page *page;
 
-	if (!virt_addr_valid(ptr))
-		return NULL;
-
-	page = virt_to_head_page(ptr);
-
-	/* Check slab allocator for flags and size. */
-	if (PageSlab(page))
-		return __check_heap_object(ptr, n, page);
+	if (virt_addr_valid(ptr)) {
+		page = virt_to_head_page(ptr);
 
+		/* Check slab allocator for flags and size. */
+		if (PageSlab(page))
+			return __check_heap_object(ptr, n, page);
 	/* Verify object does not incorrectly span multiple pages. */
-	return check_page_span(ptr, n, page, to_user);
+		return check_page_span(ptr, n, page, to_user);
+	}
+	if (likely(is_vmalloc_addr(ptr))) {
+		page = vmalloc_to_page(ptr);
+		if (unlikely(page && PagePmalloc(page)))
+			return __pmalloc_check_object(ptr, n);
+	}
+	return NULL;
 }
 
 /*
-- 
2.9.3

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[PATCH 2/3] LSM: Convert security_hook_heads into explicit array of struct list_head

[Igor Stoppa]

From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Commit 3dfc9b02864b19f4 ("LSM: Initialize security_hook_heads upon
registration.") treats "struct security_hook_heads" as an implicit array
of "struct list_head" so that we can eliminate code for static
initialization. Although we haven't encountered compilers which do not
treat sizeof(security_hook_heads) != sizeof(struct list_head) *
(sizeof(security_hook_heads) / sizeof(struct list_head)), Casey does not
like the assumption that a structure of N elements can be assumed to be
the same as an array of N elements.

Now that Kees found that randstruct complains about such casting

  security/security.c: In function 'security_init':
  security/security.c:59:20: note: found mismatched op0 struct pointer
    types: 'struct list_head' and 'struct security_hook_heads'

    struct list_head *list = (struct list_head *) &security_hook_heads;

and Christoph thinks that we should fix it rather than make randstruct
whitelist it, this patch fixes it.

It would be possible to revert commit 3dfc9b02864b19f4, but this patch
converts security_hook_heads into an explicit array of struct list_head
by introducing an enum, due to reasons explained below.

Igor proposed a sealable memory allocator, and the LSM hooks
("struct security_hook_heads security_hook_heads" and
"struct security_hook_list ...[]") will benefit from that allocator via
protection using set_memory_ro()/set_memory_rw(), and that allocator
will remove CONFIG_SECURITY_WRITABLE_HOOKS config option. Thus, we will
likely be moving to that direction.

This means that these structures will be allocated at run time using
that allocator, and therefore the address of these structures will be
determined at run time rather than compile time.

But currently, LSM_HOOK_INIT() macro depends on the address of
security_hook_heads being known at compile time. If we use an enum
so that LSM_HOOK_INIT() macro does not need to know absolute address of
security_hook_heads, it will help us to use that allocator for LSM hooks.

As a result of introducing an enum, security_hook_heads becomes a local
variable. In order to pass 80 columns check by scripts/checkpatch.pl ,
rename security_hook_heads to hook_heads.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Rebased-by: Igor Stoppa <igor.stoppa@huawei.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Igor Stoppa <igor.stoppa@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
---
 include/linux/lsm_hooks.h | 420 +++++++++++++++++++++++-----------------------
 security/security.c       |  31 ++--
 2 files changed, 227 insertions(+), 224 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 3cc9d77..32f30fa 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1694,225 +1694,226 @@ union security_list_options {
 #endif /* CONFIG_AUDIT */
 };
 
-struct security_hook_heads {
-	struct list_head binder_set_context_mgr;
-	struct list_head binder_transaction;
-	struct list_head binder_transfer_binder;
-	struct list_head binder_transfer_file;
-	struct list_head ptrace_access_check;
-	struct list_head ptrace_traceme;
-	struct list_head capget;
-	struct list_head capset;
-	struct list_head capable;
-	struct list_head quotactl;
-	struct list_head quota_on;
-	struct list_head syslog;
-	struct list_head settime;
-	struct list_head vm_enough_memory;
-	struct list_head bprm_set_creds;
-	struct list_head bprm_check_security;
-	struct list_head bprm_secureexec;
-	struct list_head bprm_committing_creds;
-	struct list_head bprm_committed_creds;
-	struct list_head sb_alloc_security;
-	struct list_head sb_free_security;
-	struct list_head sb_copy_data;
-	struct list_head sb_remount;
-	struct list_head sb_kern_mount;
-	struct list_head sb_show_options;
-	struct list_head sb_statfs;
-	struct list_head sb_mount;
-	struct list_head sb_umount;
-	struct list_head sb_pivotroot;
-	struct list_head sb_set_mnt_opts;
-	struct list_head sb_clone_mnt_opts;
-	struct list_head sb_parse_opts_str;
-	struct list_head dentry_init_security;
-	struct list_head dentry_create_files_as;
+enum security_hook_index {
+	LSM_binder_set_context_mgr,
+	LSM_binder_transaction,
+	LSM_binder_transfer_binder,
+	LSM_binder_transfer_file,
+	LSM_ptrace_access_check,
+	LSM_ptrace_traceme,
+	LSM_capget,
+	LSM_capset,
+	LSM_capable,
+	LSM_quotactl,
+	LSM_quota_on,
+	LSM_syslog,
+	LSM_settime,
+	LSM_vm_enough_memory,
+	LSM_bprm_set_creds,
+	LSM_bprm_check_security,
+	LSM_bprm_secureexec,
+	LSM_bprm_committing_creds,
+	LSM_bprm_committed_creds,
+	LSM_sb_alloc_security,
+	LSM_sb_free_security,
+	LSM_sb_copy_data,
+	LSM_sb_remount,
+	LSM_sb_kern_mount,
+	LSM_sb_show_options,
+	LSM_sb_statfs,
+	LSM_sb_mount,
+	LSM_sb_umount,
+	LSM_sb_pivotroot,
+	LSM_sb_set_mnt_opts,
+	LSM_sb_clone_mnt_opts,
+	LSM_sb_parse_opts_str,
+	LSM_dentry_init_security,
+	LSM_dentry_create_files_as,
 #ifdef CONFIG_SECURITY_PATH
-	struct list_head path_unlink;
-	struct list_head path_mkdir;
-	struct list_head path_rmdir;
-	struct list_head path_mknod;
-	struct list_head path_truncate;
-	struct list_head path_symlink;
-	struct list_head path_link;
-	struct list_head path_rename;
-	struct list_head path_chmod;
-	struct list_head path_chown;
-	struct list_head path_chroot;
+	LSM_path_unlink,
+	LSM_path_mkdir,
+	LSM_path_rmdir,
+	LSM_path_mknod,
+	LSM_path_truncate,
+	LSM_path_symlink,
+	LSM_path_link,
+	LSM_path_rename,
+	LSM_path_chmod,
+	LSM_path_chown,
+	LSM_path_chroot,
 #endif
-	struct list_head inode_alloc_security;
-	struct list_head inode_free_security;
-	struct list_head inode_init_security;
-	struct list_head inode_create;
-	struct list_head inode_link;
-	struct list_head inode_unlink;
-	struct list_head inode_symlink;
-	struct list_head inode_mkdir;
-	struct list_head inode_rmdir;
-	struct list_head inode_mknod;
-	struct list_head inode_rename;
-	struct list_head inode_readlink;
-	struct list_head inode_follow_link;
-	struct list_head inode_permission;
-	struct list_head inode_setattr;
-	struct list_head inode_getattr;
-	struct list_head inode_setxattr;
-	struct list_head inode_post_setxattr;
-	struct list_head inode_getxattr;
-	struct list_head inode_listxattr;
-	struct list_head inode_removexattr;
-	struct list_head inode_need_killpriv;
-	struct list_head inode_killpriv;
-	struct list_head inode_getsecurity;
-	struct list_head inode_setsecurity;
-	struct list_head inode_listsecurity;
-	struct list_head inode_getsecid;
-	struct list_head inode_copy_up;
-	struct list_head inode_copy_up_xattr;
-	struct list_head file_permission;
-	struct list_head file_alloc_security;
-	struct list_head file_free_security;
-	struct list_head file_ioctl;
-	struct list_head mmap_addr;
-	struct list_head mmap_file;
-	struct list_head file_mprotect;
-	struct list_head file_lock;
-	struct list_head file_fcntl;
-	struct list_head file_set_fowner;
-	struct list_head file_send_sigiotask;
-	struct list_head file_receive;
-	struct list_head file_open;
-	struct list_head task_create;
-	struct list_head task_alloc;
-	struct list_head task_free;
-	struct list_head cred_alloc_blank;
-	struct list_head cred_free;
-	struct list_head cred_prepare;
-	struct list_head cred_transfer;
-	struct list_head kernel_act_as;
-	struct list_head kernel_create_files_as;
-	struct list_head kernel_read_file;
-	struct list_head kernel_post_read_file;
-	struct list_head kernel_module_request;
-	struct list_head task_fix_setuid;
-	struct list_head task_setpgid;
-	struct list_head task_getpgid;
-	struct list_head task_getsid;
-	struct list_head task_getsecid;
-	struct list_head task_setnice;
-	struct list_head task_setioprio;
-	struct list_head task_getioprio;
-	struct list_head task_prlimit;
-	struct list_head task_setrlimit;
-	struct list_head task_setscheduler;
-	struct list_head task_getscheduler;
-	struct list_head task_movememory;
-	struct list_head task_kill;
-	struct list_head task_prctl;
-	struct list_head task_to_inode;
-	struct list_head ipc_permission;
-	struct list_head ipc_getsecid;
-	struct list_head msg_msg_alloc_security;
-	struct list_head msg_msg_free_security;
-	struct list_head msg_queue_alloc_security;
-	struct list_head msg_queue_free_security;
-	struct list_head msg_queue_associate;
-	struct list_head msg_queue_msgctl;
-	struct list_head msg_queue_msgsnd;
-	struct list_head msg_queue_msgrcv;
-	struct list_head shm_alloc_security;
-	struct list_head shm_free_security;
-	struct list_head shm_associate;
-	struct list_head shm_shmctl;
-	struct list_head shm_shmat;
-	struct list_head sem_alloc_security;
-	struct list_head sem_free_security;
-	struct list_head sem_associate;
-	struct list_head sem_semctl;
-	struct list_head sem_semop;
-	struct list_head netlink_send;
-	struct list_head d_instantiate;
-	struct list_head getprocattr;
-	struct list_head setprocattr;
-	struct list_head ismaclabel;
-	struct list_head secid_to_secctx;
-	struct list_head secctx_to_secid;
-	struct list_head release_secctx;
-	struct list_head inode_invalidate_secctx;
-	struct list_head inode_notifysecctx;
-	struct list_head inode_setsecctx;
-	struct list_head inode_getsecctx;
+	LSM_inode_alloc_security,
+	LSM_inode_free_security,
+	LSM_inode_init_security,
+	LSM_inode_create,
+	LSM_inode_link,
+	LSM_inode_unlink,
+	LSM_inode_symlink,
+	LSM_inode_mkdir,
+	LSM_inode_rmdir,
+	LSM_inode_mknod,
+	LSM_inode_rename,
+	LSM_inode_readlink,
+	LSM_inode_follow_link,
+	LSM_inode_permission,
+	LSM_inode_setattr,
+	LSM_inode_getattr,
+	LSM_inode_setxattr,
+	LSM_inode_post_setxattr,
+	LSM_inode_getxattr,
+	LSM_inode_listxattr,
+	LSM_inode_removexattr,
+	LSM_inode_need_killpriv,
+	LSM_inode_killpriv,
+	LSM_inode_getsecurity,
+	LSM_inode_setsecurity,
+	LSM_inode_listsecurity,
+	LSM_inode_getsecid,
+	LSM_inode_copy_up,
+	LSM_inode_copy_up_xattr,
+	LSM_file_permission,
+	LSM_file_alloc_security,
+	LSM_file_free_security,
+	LSM_file_ioctl,
+	LSM_mmap_addr,
+	LSM_mmap_file,
+	LSM_file_mprotect,
+	LSM_file_lock,
+	LSM_file_fcntl,
+	LSM_file_set_fowner,
+	LSM_file_send_sigiotask,
+	LSM_file_receive,
+	LSM_file_open,
+	LSM_task_create,
+	LSM_task_alloc,
+	LSM_task_free,
+	LSM_cred_alloc_blank,
+	LSM_cred_free,
+	LSM_cred_prepare,
+	LSM_cred_transfer,
+	LSM_kernel_act_as,
+	LSM_kernel_create_files_as,
+	LSM_kernel_read_file,
+	LSM_kernel_post_read_file,
+	LSM_kernel_module_request,
+	LSM_task_fix_setuid,
+	LSM_task_setpgid,
+	LSM_task_getpgid,
+	LSM_task_getsid,
+	LSM_task_getsecid,
+	LSM_task_setnice,
+	LSM_task_setioprio,
+	LSM_task_getioprio,
+	LSM_task_prlimit,
+	LSM_task_setrlimit,
+	LSM_task_setscheduler,
+	LSM_task_getscheduler,
+	LSM_task_movememory,
+	LSM_task_kill,
+	LSM_task_prctl,
+	LSM_task_to_inode,
+	LSM_ipc_permission,
+	LSM_ipc_getsecid,
+	LSM_msg_msg_alloc_security,
+	LSM_msg_msg_free_security,
+	LSM_msg_queue_alloc_security,
+	LSM_msg_queue_free_security,
+	LSM_msg_queue_associate,
+	LSM_msg_queue_msgctl,
+	LSM_msg_queue_msgsnd,
+	LSM_msg_queue_msgrcv,
+	LSM_shm_alloc_security,
+	LSM_shm_free_security,
+	LSM_shm_associate,
+	LSM_shm_shmctl,
+	LSM_shm_shmat,
+	LSM_sem_alloc_security,
+	LSM_sem_free_security,
+	LSM_sem_associate,
+	LSM_sem_semctl,
+	LSM_sem_semop,
+	LSM_netlink_send,
+	LSM_d_instantiate,
+	LSM_getprocattr,
+	LSM_setprocattr,
+	LSM_ismaclabel,
+	LSM_secid_to_secctx,
+	LSM_secctx_to_secid,
+	LSM_release_secctx,
+	LSM_inode_invalidate_secctx,
+	LSM_inode_notifysecctx,
+	LSM_inode_setsecctx,
+	LSM_inode_getsecctx,
 #ifdef CONFIG_SECURITY_NETWORK
-	struct list_head unix_stream_connect;
-	struct list_head unix_may_send;
-	struct list_head socket_create;
-	struct list_head socket_post_create;
-	struct list_head socket_bind;
-	struct list_head socket_connect;
-	struct list_head socket_listen;
-	struct list_head socket_accept;
-	struct list_head socket_sendmsg;
-	struct list_head socket_recvmsg;
-	struct list_head socket_getsockname;
-	struct list_head socket_getpeername;
-	struct list_head socket_getsockopt;
-	struct list_head socket_setsockopt;
-	struct list_head socket_shutdown;
-	struct list_head socket_sock_rcv_skb;
-	struct list_head socket_getpeersec_stream;
-	struct list_head socket_getpeersec_dgram;
-	struct list_head sk_alloc_security;
-	struct list_head sk_free_security;
-	struct list_head sk_clone_security;
-	struct list_head sk_getsecid;
-	struct list_head sock_graft;
-	struct list_head inet_conn_request;
-	struct list_head inet_csk_clone;
-	struct list_head inet_conn_established;
-	struct list_head secmark_relabel_packet;
-	struct list_head secmark_refcount_inc;
-	struct list_head secmark_refcount_dec;
-	struct list_head req_classify_flow;
-	struct list_head tun_dev_alloc_security;
-	struct list_head tun_dev_free_security;
-	struct list_head tun_dev_create;
-	struct list_head tun_dev_attach_queue;
-	struct list_head tun_dev_attach;
-	struct list_head tun_dev_open;
+	LSM_unix_stream_connect,
+	LSM_unix_may_send,
+	LSM_socket_create,
+	LSM_socket_post_create,
+	LSM_socket_bind,
+	LSM_socket_connect,
+	LSM_socket_listen,
+	LSM_socket_accept,
+	LSM_socket_sendmsg,
+	LSM_socket_recvmsg,
+	LSM_socket_getsockname,
+	LSM_socket_getpeername,
+	LSM_socket_getsockopt,
+	LSM_socket_setsockopt,
+	LSM_socket_shutdown,
+	LSM_socket_sock_rcv_skb,
+	LSM_socket_getpeersec_stream,
+	LSM_socket_getpeersec_dgram,
+	LSM_sk_alloc_security,
+	LSM_sk_free_security,
+	LSM_sk_clone_security,
+	LSM_sk_getsecid,
+	LSM_sock_graft,
+	LSM_inet_conn_request,
+	LSM_inet_csk_clone,
+	LSM_inet_conn_established,
+	LSM_secmark_relabel_packet,
+	LSM_secmark_refcount_inc,
+	LSM_secmark_refcount_dec,
+	LSM_req_classify_flow,
+	LSM_tun_dev_alloc_security,
+	LSM_tun_dev_free_security,
+	LSM_tun_dev_create,
+	LSM_tun_dev_attach_queue,
+	LSM_tun_dev_attach,
+	LSM_tun_dev_open,
 #endif	/* CONFIG_SECURITY_NETWORK */
 #ifdef CONFIG_SECURITY_INFINIBAND
-	struct list_head ib_pkey_access;
-	struct list_head ib_endport_manage_subnet;
-	struct list_head ib_alloc_security;
-	struct list_head ib_free_security;
+	LSM_ib_pkey_access,
+	LSM_ib_endport_manage_subnet,
+	LSM_ib_alloc_security,
+	LSM_ib_free_security,
 #endif	/* CONFIG_SECURITY_INFINIBAND */
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
-	struct list_head xfrm_policy_alloc_security;
-	struct list_head xfrm_policy_clone_security;
-	struct list_head xfrm_policy_free_security;
-	struct list_head xfrm_policy_delete_security;
-	struct list_head xfrm_state_alloc;
-	struct list_head xfrm_state_alloc_acquire;
-	struct list_head xfrm_state_free_security;
-	struct list_head xfrm_state_delete_security;
-	struct list_head xfrm_policy_lookup;
-	struct list_head xfrm_state_pol_flow_match;
-	struct list_head xfrm_decode_session;
+	LSM_xfrm_policy_alloc_security,
+	LSM_xfrm_policy_clone_security,
+	LSM_xfrm_policy_free_security,
+	LSM_xfrm_policy_delete_security,
+	LSM_xfrm_state_alloc,
+	LSM_xfrm_state_alloc_acquire,
+	LSM_xfrm_state_free_security,
+	LSM_xfrm_state_delete_security,
+	LSM_xfrm_policy_lookup,
+	LSM_xfrm_state_pol_flow_match,
+	LSM_xfrm_decode_session,
 #endif	/* CONFIG_SECURITY_NETWORK_XFRM */
 #ifdef CONFIG_KEYS
-	struct list_head key_alloc;
-	struct list_head key_free;
-	struct list_head key_permission;
-	struct list_head key_getsecurity;
+	LSM_key_alloc,
+	LSM_key_free,
+	LSM_key_permission,
+	LSM_key_getsecurity,
 #endif	/* CONFIG_KEYS */
 #ifdef CONFIG_AUDIT
-	struct list_head audit_rule_init;
-	struct list_head audit_rule_known;
-	struct list_head audit_rule_match;
-	struct list_head audit_rule_free;
+	LSM_audit_rule_init,
+	LSM_audit_rule_known,
+	LSM_audit_rule_match,
+	LSM_audit_rule_free,
 #endif /* CONFIG_AUDIT */
+	LSM_MAX_HOOK_INDEX,
 };
 
 /*
@@ -1921,8 +1922,8 @@ struct security_hook_heads {
  */
 struct security_hook_list {
 	struct list_head		list;
-	struct list_head		*head;
 	union security_list_options	hook;
+	enum security_hook_index	idx;
 	char				*lsm;
 };
 
@@ -1933,9 +1934,8 @@ struct security_hook_list {
  * text involved.
  */
 #define LSM_HOOK_INIT(HEAD, HOOK) \
-	{ .head = &security_hook_heads.HEAD, .hook = { .HEAD = HOOK } }
+	{ .idx = LSM_##HEAD, .hook = { .HEAD = HOOK } }
 
-extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
diff --git a/security/security.c b/security/security.c
index 3013237..44c47b6 100644
--- a/security/security.c
+++ b/security/security.c
@@ -34,7 +34,8 @@
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
-struct security_hook_heads security_hook_heads __lsm_ro_after_init;
+static struct list_head hook_heads[LSM_MAX_HOOK_INDEX]
+	__lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
 char *lsm_names;
@@ -59,12 +60,10 @@ static void __init do_security_initcalls(void)
  */
 int __init security_init(void)
 {
-	int i;
-	struct list_head *list = (struct list_head *) &security_hook_heads;
+	enum security_hook_index i;
 
-	for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct list_head);
-	     i++)
-		INIT_LIST_HEAD(&list[i]);
+	for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
+		INIT_LIST_HEAD(&hook_heads[i]);
 	pr_info("Security Framework initialized\n");
 
 	/*
@@ -161,8 +160,12 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	int i;
 
 	for (i = 0; i < count; i++) {
+		enum security_hook_index idx = hooks[i].idx;
+
 		hooks[i].lsm = lsm;
-		list_add_tail_rcu(&hooks[i].list, hooks[i].head);
+		/* Can't hit this BUG_ON() unless LSM_HOOK_INIT() is broken. */
+		BUG_ON(idx < 0 || idx >= LSM_MAX_HOOK_INDEX);
+		list_add_tail_rcu(&hooks[i].list, &hook_heads[idx]);
 	}
 	if (lsm_append(lsm, &lsm_names) < 0)
 		panic("%s - Cannot get early memory.\n", __func__);
@@ -200,7 +203,7 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
 	do {							\
 		struct security_hook_list *P;			\
 								\
-		list_for_each_entry(P, &security_hook_heads.FUNC, list)	\
+		list_for_each_entry(P, &hook_heads[LSM_##FUNC], list)	\
 			P->hook.FUNC(__VA_ARGS__);		\
 	} while (0)
 
@@ -209,7 +212,7 @@ EXPORT_SYMBOL(unregister_lsm_notifier);
 	do {							\
 		struct security_hook_list *P;			\
 								\
-		list_for_each_entry(P, &security_hook_heads.FUNC, list) { \
+		list_for_each_entry(P, &hook_heads[LSM_##FUNC], list) {	\
 			RC = P->hook.FUNC(__VA_ARGS__);		\
 			if (RC != 0)				\
 				break;				\
@@ -316,7 +319,7 @@ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
 	 * agree that it should be set it will. If any module
 	 * thinks it should not be set it won't.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) {
+	list_for_each_entry(hp, &hook_heads[LSM_vm_enough_memory], list) {
 		rc = hp->hook.vm_enough_memory(mm, pages);
 		if (rc <= 0) {
 			cap_sys_admin = 0;
@@ -809,7 +812,7 @@ int security_inode_getsecurity(struct inode *inode, const char *name, void **buf
 	/*
 	 * Only one module will provide an attribute with a given name.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) {
+	list_for_each_entry(hp, &hook_heads[LSM_inode_getsecurity], list) {
 		rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc);
 		if (rc != -EOPNOTSUPP)
 			return rc;
@@ -827,7 +830,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void
 	/*
 	 * Only one module will provide an attribute with a given name.
 	 */
-	list_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) {
+	list_for_each_entry(hp, &hook_heads[LSM_inode_setsecurity], list) {
 		rc = hp->hook.inode_setsecurity(inode, name, value, size,
 								flags);
 		if (rc != -EOPNOTSUPP)
@@ -1135,7 +1138,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 	int rc = -ENOSYS;
 	struct security_hook_list *hp;
 
-	list_for_each_entry(hp, &security_hook_heads.task_prctl, list) {
+	list_for_each_entry(hp, &hook_heads[LSM_task_prctl], list) {
 		thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5);
 		if (thisrc != -ENOSYS) {
 			rc = thisrc;
@@ -1638,7 +1641,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
 	 * For speed optimization, we explicitly break the loop rather than
 	 * using the macro
 	 */
-	list_for_each_entry(hp, &security_hook_heads.xfrm_state_pol_flow_match,
+	list_for_each_entry(hp, &hook_heads[LSM_xfrm_state_pol_flow_match],
 				list) {
 		rc = hp->hook.xfrm_state_pol_flow_match(x, xp, fl);
 		break;
-- 
2.9.3

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[PATCH 3/3] Make LSM Writable Hooks a command line option

[Igor Stoppa]

This patch shows how it is possible to take advantage of pmalloc:
instead of using the build-time option __lsm_ro_after_init, to decide if
it is possible to keep the hooks modifiable, now this becomes a
boot-time decision, based on the kernel command line.

This patch relies on:

"Convert security_hook_heads into explicit array of struct list_head"
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

to break free from the static constraint imposed by the previous
hardening model, based on __ro_after_init.

The default value is disabled, unless SE Linux debugging is turned on.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/security.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/security/security.c b/security/security.c
index 44c47b6..c7b4670 100644
--- a/security/security.c
+++ b/security/security.c
@@ -27,6 +27,7 @@
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
 #include <linux/string.h>
+#include <linux/pmalloc.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -34,10 +35,19 @@
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
-static struct list_head hook_heads[LSM_MAX_HOOK_INDEX]
-	__lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
+static int dynamic_lsm = IS_ENABLED(CONFIG_SECURITY_SELINUX_DISABLE);
+
+static __init int set_dynamic_lsm(char *str)
+{
+	get_option(&str, &dynamic_lsm);
+	return 0;
+}
+early_param("dynamic_lsm", set_dynamic_lsm);
+
+static struct list_head *hook_heads;
+static struct gen_pool *sec_pool;
 char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
@@ -62,6 +72,11 @@ int __init security_init(void)
 {
 	enum security_hook_index i;
 
+	sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER);
+	BUG_ON(!sec_pool);
+	hook_heads = pmalloc(sec_pool,
+			     sizeof(struct list_head) * LSM_MAX_HOOK_INDEX);
+	BUG_ON(!hook_heads);
 	for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
 		INIT_LIST_HEAD(&hook_heads[i]);
 	pr_info("Security Framework initialized\n");
@@ -77,7 +92,8 @@ int __init security_init(void)
 	 * Load all the remaining security modules.
 	 */
 	do_security_initcalls();
-
+	if (!dynamic_lsm)
+		pmalloc_protect_pool(sec_pool);
 	return 0;
 }
 
-- 
2.9.3

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Re: [PATCH 1/3] Protectable memory support

[Jerome Glisse]

On Wed, Jul 05, 2017 at 04:46:26PM +0300, Igor Stoppa wrote:
> The MMU available in many systems running Linux can often provide R/O
> protection to the memory pages it handles.
> 
> However, the MMU-based protection works efficiently only when said pages
> contain exclusively data that will not need further modifications.
> 
> Statically allocated variables can be segregated into a dedicated
> section, but this does not sit very well with dynamically allocated ones.
> 
> Dynamic allocation does not provide, currently, any means for grouping
> variables in memory pages that would contain exclusively data suitable
> for conversion to read only access mode.
> 
> The allocator here provided (pmalloc - protectable memory allocator)
> introduces the concept of pools of protectable memory.
> 
> A module can request a pool and then refer any allocation request to the
> pool handler it has received.
> 
> Once all the chunks of memory associated to a specific pool are
> initialized, the pool can be protected.
> 
> After this point, the pool can only be destroyed (it is up to the module
> to avoid any further references to the memory from the pool, after
> the destruction is invoked).
> 
> The latter case is mainly meant for releasing memory, when a module is
> unloaded.
> 
> A module can have as many pools as needed, for example to support the
> protection of data that is initialized in sufficiently distinct phases.
> 
> Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
> ---
>  arch/Kconfig                   |   1 +
>  include/linux/page-flags.h     |   2 +
>  include/linux/pmalloc.h        | 127 +++++++++++++++
>  include/trace/events/mmflags.h |   1 +
>  lib/Kconfig                    |   1 +
>  mm/Makefile                    |   1 +
>  mm/pmalloc.c                   | 356 +++++++++++++++++++++++++++++++++++++++++
>  mm/usercopy.c                  |  24 +--
>  8 files changed, 504 insertions(+), 9 deletions(-)
>  create mode 100644 include/linux/pmalloc.h
>  create mode 100644 mm/pmalloc.c
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 6c00e5b..9d16b51 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -228,6 +228,7 @@ config GENERIC_IDLE_POLL_SETUP
>  
>  # Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
>  config ARCH_HAS_SET_MEMORY
> +	select GENERIC_ALLOCATOR
>  	bool
>  
>  # Select if arch init_task initializer is different to init/init_task.c
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 6b5818d..acc0723 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -81,6 +81,7 @@ enum pageflags {
>  	PG_active,
>  	PG_waiters,		/* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
>  	PG_slab,
> +	PG_pmalloc,
>  	PG_owner_priv_1,	/* Owner use. If pagecache, fs may use*/
>  	PG_arch_1,
>  	PG_reserved,
> @@ -274,6 +275,7 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
>  	TESTCLEARFLAG(Active, active, PF_HEAD)
>  __PAGEFLAG(Slab, slab, PF_NO_TAIL)
>  __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
> +__PAGEFLAG(Pmalloc, pmalloc, PF_NO_TAIL)
>  PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
>  
>  /* Xen */


So i don't think we want to waste a page flag on this. The struct 
page flags field is already full AFAIK (see page-flags-layout.h)

Moreover there is easier way to tag such page. So my understanding
is that pmalloc() is always suppose to be in vmalloc area. From
the look of it all you do is check that there is a valid page behind
the vmalloc vaddr and you check for the PG_malloc flag of that page.

Why do you need to check the PG_malloc flag for the page ? Isn't the
fact that there is a page behind the vmalloc vaddr enough ? If not
enough wouldn't checking the pte flags of the page enough ? ie if
the page is read only inside vmalloc than it would be for sure some
pmalloc area.

Other way to distinguish between regular vmalloc and pmalloc can be
to carveout a region of vmalloc for pmalloc purpose. Issue is that
it might be hard to find right size for such carveout.

Yet another way is to use some of the free struct page fields ie
when a page is allocated for vmalloc i think most of struct page
fields are unuse (mapping, index, lru, ...). It would be better
to use those rather than adding a page flag.


Everything else looks good to me, thought i am unsure on how much
useful such feature is but i am not familiar too much with security
side of thing.


Cheers,
Jerome

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Re: [PATCH 1/3] Protectable memory support

[Igor Stoppa]

On 06/07/17 19:27, Jerome Glisse wrote:
> On Wed, Jul 05, 2017 at 04:46:26PM +0300, Igor Stoppa wrote:

[...]

>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
>> index 6b5818d..acc0723 100644
>> --- a/include/linux/page-flags.h
>> +++ b/include/linux/page-flags.h
>> @@ -81,6 +81,7 @@ enum pageflags {
>>  	PG_active,
>>  	PG_waiters,		/* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
>>  	PG_slab,
>> +	PG_pmalloc,
>>  	PG_owner_priv_1,	/* Owner use. If pagecache, fs may use*/
>>  	PG_arch_1,
>>  	PG_reserved,
>> @@ -274,6 +275,7 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
>>  	TESTCLEARFLAG(Active, active, PF_HEAD)
>>  __PAGEFLAG(Slab, slab, PF_NO_TAIL)
>>  __PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
>> +__PAGEFLAG(Pmalloc, pmalloc, PF_NO_TAIL)
>>  PAGEFLAG(Checked, checked, PF_NO_COMPOUND)	   /* Used by some filesystems */
>>  
>>  /* Xen */
> 
> 
> So i don't think we want to waste a page flag on this. The struct 
> page flags field is already full AFAIK (see page-flags-layout.h)

okay, I do not have any specific need to have a page flag, if there is
an equally effective way to identify pages that are served by pmalloc.
I just replicated what seemed to be the typical way.

> Moreover there is easier way to tag such page. So my understanding
> is that pmalloc() is always suppose to be in vmalloc area. 

At least for now, yes.
I need to have some sort of memory-provider backend.
I tried to use a dedicated memory zone and kmalloc [1] but it was
explained to me that it would have been a bad idea.
So I defaulted to vmalloc and so far it didn't rise any objection.

> From
> the look of it all you do is check that there is a valid page behind
> the vmalloc vaddr and you check for the PG_malloc flag of that page.
> 
> Why do you need to check the PG_malloc flag for the page ? Isn't the
> fact that there is a page behind the vmalloc vaddr enough ? If not
> enough wouldn't checking the pte flags of the page enough ? ie if
> the page is read only inside vmalloc than it would be for sure some
> pmalloc area.

I had similar discussion with Kees Cook [2].
The reason why he asked me to differentiate between pmalloc and vmalloc
is that, from security perspective, there is a certain amount of
information associated to the fact that a page was obtained through
pmalloc. Checking only for pmalloc, would discard such information and
relax the constraint enforced from hardened user copy.

> Other way to distinguish between regular vmalloc and pmalloc can be
> to carveout a region of vmalloc for pmalloc purpose. Issue is that
> it might be hard to find right size for such carveout.

Yes, I considered that, but I'd prefer to avoid it, because then I
either have to fix the maximum size of such region or start managing the
creation of pools of pools. I'm not a big fan of such idea.

> Yet another way is to use some of the free struct page fields ie
> when a page is allocated for vmalloc i think most of struct page
> fields are unuse (mapping, index, lru, ...). It would be better
> to use those rather than adding a page flag.

Like introducing an unnamed union? Some sort of vmalloc_page_subtype?
If that is what you are proposing, I agree that it would work in a
similar fashion as what I have now, but without introducing the overhead
of the extra page flag.

@Kees: would this be ok from a hardened usercopy perspective?

> Everything else looks good to me, thought i am unsure on how much
> useful such feature is but i am not familiar too much with security
> side of thing.

The other 2 patches from the patchset give an example of how to turn a
compile time decision (locking down after init or not the lsm hooks)
into a boot time option.

I also want to move the SE Linux policy db to use pmalloc as allocator,
once pmalloc is merged.

But it seemed better to first get pmalloc merged and only after start
the policy db rework.

thanks, igor

[1] https://lkml.org/lkml/2017/5/4/517
[2] https://lkml.org/lkml/2017/5/23/1406

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Re: [PATCH 1/3] Protectable memory support

[Jerome Glisse]

On Fri, Jul 07, 2017 at 11:42:09AM +0300, Igor Stoppa wrote:
> On 06/07/17 19:27, Jerome Glisse wrote:
> > On Wed, Jul 05, 2017 at 04:46:26PM +0300, Igor Stoppa wrote:

[...]

> > Yet another way is to use some of the free struct page fields ie
> > when a page is allocated for vmalloc i think most of struct page
> > fields are unuse (mapping, index, lru, ...). It would be better
> > to use those rather than adding a page flag.
> 
> Like introducing an unnamed union? Some sort of vmalloc_page_subtype?
> If that is what you are proposing, I agree that it would work in a
> similar fashion as what I have now, but without introducing the overhead
> of the extra page flag.

No need to introduce unamed union or anything. Just use one of the
existing field for install you can make page->mapping point to the
pmalloc pool structure. Or you can store a unique key value.

I believe there is enough unuse field that for vmalloc pages that
you should find one you can use. Just add some documentation in
mm_types.h so people are aware of alternate use for the field you
are using.

Jerome

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Re: [PATCH 1/3] Protectable memory support

[Igor Stoppa]

On 07/07/17 21:48, Jerome Glisse wrote:

> I believe there is enough unuse field that for vmalloc pages that
> you should find one you can use. Just add some documentation in
> mm_types.h so people are aware of alternate use for the field you
> are using.


I ended up using page->private and the corresponding bit.
Because page-private is an opaque field, specifically reserved for the
allocator, I think it should not be necessary to modify mm_types.h

The reworked patch is here:
https://marc.info/?l=linux-mm&m=149969928920772&w=2

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thanks, igor

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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1123 bytes --]

Hi Igor,

[auto build test ERROR on linus/master]
[cannot apply to v4.12]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Igor-Stoppa/mm-security-ro-protection-for-dynamic-data/20170711-084116
config: score-spct6600_defconfig (attached as .config)
compiler: score-elf-gcc (GCC) 4.9.1 20140622 (prerelease)
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=score 

All errors (new ones prefixed by >>):

   security/security.o: In function `security_init':
>> security.c:(.init.text+0x68): undefined reference to `pmalloc_create_pool'
>> security.c:(.init.text+0x98): undefined reference to `pmalloc'
>> security.c:(.init.text+0x150): undefined reference to `pmalloc_protect_pool'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 7884 bytes --]

[PATCH 3/3] Make LSM Writable Hooks a command line option

[Igor Stoppa]

This patch shows how it is possible to take advantage of pmalloc:
instead of using the build-time option __lsm_ro_after_init, to decide if
it is possible to keep the hooks modifiable, now this becomes a
boot-time decision, based on the kernel command line.

This patch relies on:

"Convert security_hook_heads into explicit array of struct list_head"
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

to break free from the static constraint imposed by the previous
hardening model, based on __ro_after_init.

The default value is disabled, unless SE Linux debugging is turned on.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/security.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/security/security.c b/security/security.c
index 44c47b6..c7b4670 100644
--- a/security/security.c
+++ b/security/security.c
@@ -27,6 +27,7 @@
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
 #include <linux/string.h>
+#include <linux/pmalloc.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -34,10 +35,19 @@
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
-static struct list_head hook_heads[LSM_MAX_HOOK_INDEX]
-	__lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
+static int dynamic_lsm = IS_ENABLED(CONFIG_SECURITY_SELINUX_DISABLE);
+
+static __init int set_dynamic_lsm(char *str)
+{
+	get_option(&str, &dynamic_lsm);
+	return 0;
+}
+early_param("dynamic_lsm", set_dynamic_lsm);
+
+static struct list_head *hook_heads;
+static struct gen_pool *sec_pool;
 char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
@@ -62,6 +72,11 @@ int __init security_init(void)
 {
 	enum security_hook_index i;
 
+	sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER);
+	BUG_ON(!sec_pool);
+	hook_heads = pmalloc(sec_pool,
+			     sizeof(struct list_head) * LSM_MAX_HOOK_INDEX);
+	BUG_ON(!hook_heads);
 	for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
 		INIT_LIST_HEAD(&hook_heads[i]);
 	pr_info("Security Framework initialized\n");
@@ -77,7 +92,8 @@ int __init security_init(void)
 	 * Load all the remaining security modules.
 	 */
 	do_security_initcalls();
-
+	if (!dynamic_lsm)
+		pmalloc_protect_pool(sec_pool);
 	return 0;
 }
 
-- 
2.9.3

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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[Igor Stoppa]

Resending my reply, I mistakenly used the wrong mail account yesterday
and my reply didn't et to the ml.

On 27/06/17 20:51, Christoph Hellwig wrote:
> On Tue, Jun 27, 2017 at 08:33:23PM +0300, Igor Stoppa wrote:

[...]

>> The default value is disabled, unless SE Linux debugging is turned on.
> 
> Can we please just force it to be read-only?

I'm sorry, I'm not quite sure I understand your comment.

I'm trying to replicate the behavior of __lsm_ro_after_init:

line 1967 @ [1]   - Did I get it wrong?

thanks, igor



[1]
https://kernel.googlesource.com/pub/scm/linux/kernel/git/jmorris/linux-security/+/5965453d5e3fb425e6f9d6b4fec403bda3f33107/include/linux/lsm_hooks.h

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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[igor.stoppa]

[-- Attachment #1: Type: text/plain, Size: 604 bytes --]

On 27 June 2017 at 20:51, Christoph Hellwig <hch@infradead.org> wrote:

> On Tue, Jun 27, 2017 at 08:33:23PM +0300, Igor Stoppa wrote:
>
> [...]


> > The default value is disabled, unless SE Linux debugging is turned on.
>
> Can we please just force it to be read-only?
>

I'm sorry, I'm not quite sure I understand your comment.

I'm trying to replicate the behavior of __lsm_ro_after_init:

line 1967 @ [1]   - Did I get it wrong?

thanks, igor



[1]
https://kernel.googlesource.com/pub/scm/linux/kernel/git/jmorris/linux-security/+/5965453d5e3fb425e6f9d6b4fec403bda3f33107/include/linux/lsm_hooks.h

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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[Christoph Hellwig]

On Tue, Jun 27, 2017 at 08:33:23PM +0300, Igor Stoppa wrote:
> From: Igor Stoppa <igor.stoppa@gmail.com>
> 
> This patch shows how it is possible to take advantage of pmalloc:
> instead of using the build-time option __lsm_ro_after_init, to decide if
> it is possible to keep the hooks modifiable, now this becomes a
> boot-time decision, based on the kernel command line.
> 
> This patch relies on:
> 
> "Convert security_hook_heads into explicit array of struct list_head"
> Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> to break free from the static constraint imposed by the previous
> hardening model, based on __ro_after_init.
> 
> The default value is disabled, unless SE Linux debugging is turned on.

Can we please just force it to be read-only?

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[PATCH 3/3] Make LSM Writable Hooks a command line option

[Igor Stoppa]

From: Igor Stoppa <igor.stoppa@gmail.com>

This patch shows how it is possible to take advantage of pmalloc:
instead of using the build-time option __lsm_ro_after_init, to decide if
it is possible to keep the hooks modifiable, now this becomes a
boot-time decision, based on the kernel command line.

This patch relies on:

"Convert security_hook_heads into explicit array of struct list_head"
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

to break free from the static constraint imposed by the previous
hardening model, based on __ro_after_init.

The default value is disabled, unless SE Linux debugging is turned on.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/security.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/security/security.c b/security/security.c
index 44c47b6..c7b4670 100644
--- a/security/security.c
+++ b/security/security.c
@@ -27,6 +27,7 @@
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
 #include <linux/string.h>
+#include <linux/pmalloc.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -34,10 +35,19 @@
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
-static struct list_head hook_heads[LSM_MAX_HOOK_INDEX]
-	__lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
+static int dynamic_lsm = IS_ENABLED(CONFIG_SECURITY_SELINUX_DISABLE);
+
+static __init int set_dynamic_lsm(char *str)
+{
+	get_option(&str, &dynamic_lsm);
+	return 0;
+}
+early_param("dynamic_lsm", set_dynamic_lsm);
+
+static struct list_head *hook_heads;
+static struct gen_pool *sec_pool;
 char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
@@ -62,6 +72,11 @@ int __init security_init(void)
 {
 	enum security_hook_index i;
 
+	sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER);
+	BUG_ON(!sec_pool);
+	hook_heads = pmalloc(sec_pool,
+			     sizeof(struct list_head) * LSM_MAX_HOOK_INDEX);
+	BUG_ON(!hook_heads);
 	for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
 		INIT_LIST_HEAD(&hook_heads[i]);
 	pr_info("Security Framework initialized\n");
@@ -77,7 +92,8 @@ int __init security_init(void)
 	 * Load all the remaining security modules.
 	 */
 	do_security_initcalls();
-
+	if (!dynamic_lsm)
+		pmalloc_protect_pool(sec_pool);
 	return 0;
 }
 
-- 
2.9.3

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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2268 bytes --]

Hi Igor,

[auto build test ERROR on mmotm/master]
[cannot apply to linus/master linux/master v4.12-rc7 next-20170626]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Igor-Stoppa/ro-protection-for-dynamic-data/20170627-103230
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: tile-tilegx_defconfig (attached as .config)
compiler: tilegx-linux-gcc (GCC) 4.6.2
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=tile 

All errors (new ones prefixed by >>):

   init/built-in.o: In function `start_kernel':
   init/main.c:678: undefined reference to `pmalloc_init'
   security/built-in.o: In function `security_init':
>> security/security.c:75: undefined reference to `pmalloc_create_pool'
>> security/security.c:77: undefined reference to `pmalloc'
>> security/security.c:96: undefined reference to `pmalloc_protect_pool'

vim +75 security/security.c

    69	 * This should be called early in the kernel initialization sequence.
    70	 */
    71	int __init security_init(void)
    72	{
    73		enum security_hook_index i;
    74	
  > 75		sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER);
    76		BUG_ON(!sec_pool);
  > 77		hook_heads = pmalloc(sec_pool,
    78				     sizeof(struct list_head) * LSM_MAX_HOOK_INDEX);
    79		BUG_ON(!hook_heads);
    80		for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
    81			INIT_LIST_HEAD(&hook_heads[i]);
    82		pr_info("Security Framework initialized\n");
    83	
    84		/*
    85		 * Load minor LSMs, with the capability module always first.
    86		 */
    87		capability_add_hooks();
    88		yama_add_hooks();
    89		loadpin_add_hooks();
    90	
    91		/*
    92		 * Load all the remaining security modules.
    93		 */
    94		do_security_initcalls();
    95		if (!dynamic_lsm)
  > 96			pmalloc_protect_pool(sec_pool);
    97		return 0;
    98	}
    99	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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Re: [PATCH 3/3] Make LSM Writable Hooks a command line option

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1486 bytes --]

Hi Igor,

[auto build test ERROR on mmotm/master]
[cannot apply to linus/master linux/master v4.12-rc7 next-20170626]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Igor-Stoppa/ro-protection-for-dynamic-data/20170627-103230
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 6.2.0
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=ia64 

All errors (new ones prefixed by >>):

   init/built-in.o: In function `start_kernel':
   (.init.text+0x1832): undefined reference to `pmalloc_init'
   mm/built-in.o: In function `__check_object_size':
   (.text+0x14f1b2): undefined reference to `__pmalloc_check_object'
   security/built-in.o: In function `security_init':
>> (.init.text+0x802): undefined reference to `pmalloc_create_pool'
   security/built-in.o: In function `security_init':
>> (.init.text+0x832): undefined reference to `pmalloc'
   security/built-in.o: In function `security_init':
>> (.init.text+0x9d2): undefined reference to `pmalloc_protect_pool'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 48169 bytes --]

[PATCH 3/3] Make LSM Writable Hooks a command line option

[Igor Stoppa]

From: Igor Stoppa <igor.stoppa@gmail.com>

This patch shows how it is possible to take advantage of pmalloc:
instead of using the build-time option __lsm_ro_after_init, to decide if
it is possible to keep the hooks modifiable, now this becomes a
boot-time decision, based on the kernel command line.

This patch relies on:

"Convert security_hook_heads into explicit array of struct list_head"
Author: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

to break free from the static constraint imposed by the previous
hardening model, based on __ro_after_init.

The default value is disabled, unless SE Linux debugging is turned on.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 security/security.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/security/security.c b/security/security.c
index 44c47b6..c7b4670 100644
--- a/security/security.c
+++ b/security/security.c
@@ -27,6 +27,7 @@
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
 #include <linux/string.h>
+#include <linux/pmalloc.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -34,10 +35,19 @@
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
-static struct list_head hook_heads[LSM_MAX_HOOK_INDEX]
-	__lsm_ro_after_init;
 static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
 
+static int dynamic_lsm = IS_ENABLED(CONFIG_SECURITY_SELINUX_DISABLE);
+
+static __init int set_dynamic_lsm(char *str)
+{
+	get_option(&str, &dynamic_lsm);
+	return 0;
+}
+early_param("dynamic_lsm", set_dynamic_lsm);
+
+static struct list_head *hook_heads;
+static struct gen_pool *sec_pool;
 char *lsm_names;
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
@@ -62,6 +72,11 @@ int __init security_init(void)
 {
 	enum security_hook_index i;
 
+	sec_pool = pmalloc_create_pool("security", PMALLOC_DEFAULT_ALLOC_ORDER);
+	BUG_ON(!sec_pool);
+	hook_heads = pmalloc(sec_pool,
+			     sizeof(struct list_head) * LSM_MAX_HOOK_INDEX);
+	BUG_ON(!hook_heads);
 	for (i = 0; i < LSM_MAX_HOOK_INDEX; i++)
 		INIT_LIST_HEAD(&hook_heads[i]);
 	pr_info("Security Framework initialized\n");
@@ -77,7 +92,8 @@ int __init security_init(void)
 	 * Load all the remaining security modules.
 	 */
 	do_security_initcalls();
-
+	if (!dynamic_lsm)
+		pmalloc_protect_pool(sec_pool);
 	return 0;
 }
 
-- 
2.9.3

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