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linux/drivers/android/binder_alloc.h
Todd Kjos 0f966cba95 binder: add flag to clear buffer on txn complete
Add a per-transaction flag to indicate that the buffer
must be cleared when the transaction is complete to
prevent copies of sensitive data from being preserved
in memory.

Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20201120233743.3617529-1-tkjos@google.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 15:41:21 +01:00

181 lines
6.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2017 Google, Inc.
*/
#ifndef _LINUX_BINDER_ALLOC_H
#define _LINUX_BINDER_ALLOC_H
#include <linux/rbtree.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/rtmutex.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/list_lru.h>
#include <uapi/linux/android/binder.h>
extern struct list_lru binder_alloc_lru;
struct binder_transaction;
/**
* struct binder_buffer - buffer used for binder transactions
* @entry: entry alloc->buffers
* @rb_node: node for allocated_buffers/free_buffers rb trees
* @free: %true if buffer is free
* @clear_on_free: %true if buffer must be zeroed after use
* @allow_user_free: %true if user is allowed to free buffer
* @async_transaction: %true if buffer is in use for an async txn
* @debug_id: unique ID for debugging
* @transaction: pointer to associated struct binder_transaction
* @target_node: struct binder_node associated with this buffer
* @data_size: size of @transaction data
* @offsets_size: size of array of offsets
* @extra_buffers_size: size of space for other objects (like sg lists)
* @user_data: user pointer to base of buffer space
* @pid: pid to attribute the buffer to (caller)
*
* Bookkeeping structure for binder transaction buffers
*/
struct binder_buffer {
struct list_head entry; /* free and allocated entries by address */
struct rb_node rb_node; /* free entry by size or allocated entry */
/* by address */
unsigned free:1;
unsigned clear_on_free:1;
unsigned allow_user_free:1;
unsigned async_transaction:1;
unsigned debug_id:28;
struct binder_transaction *transaction;
struct binder_node *target_node;
size_t data_size;
size_t offsets_size;
size_t extra_buffers_size;
void __user *user_data;
int pid;
};
/**
* struct binder_lru_page - page object used for binder shrinker
* @page_ptr: pointer to physical page in mmap'd space
* @lru: entry in binder_alloc_lru
* @alloc: binder_alloc for a proc
*/
struct binder_lru_page {
struct list_head lru;
struct page *page_ptr;
struct binder_alloc *alloc;
};
/**
* struct binder_alloc - per-binder proc state for binder allocator
* @vma: vm_area_struct passed to mmap_handler
* (invarient after mmap)
* @tsk: tid for task that called init for this proc
* (invariant after init)
* @vma_vm_mm: copy of vma->vm_mm (invarient after mmap)
* @buffer: base of per-proc address space mapped via mmap
* @buffers: list of all buffers for this proc
* @free_buffers: rb tree of buffers available for allocation
* sorted by size
* @allocated_buffers: rb tree of allocated buffers sorted by address
* @free_async_space: VA space available for async buffers. This is
* initialized at mmap time to 1/2 the full VA space
* @pages: array of binder_lru_page
* @buffer_size: size of address space specified via mmap
* @pid: pid for associated binder_proc (invariant after init)
* @pages_high: high watermark of offset in @pages
*
* Bookkeeping structure for per-proc address space management for binder
* buffers. It is normally initialized during binder_init() and binder_mmap()
* calls. The address space is used for both user-visible buffers and for
* struct binder_buffer objects used to track the user buffers
*/
struct binder_alloc {
struct mutex mutex;
struct vm_area_struct *vma;
struct mm_struct *vma_vm_mm;
void __user *buffer;
struct list_head buffers;
struct rb_root free_buffers;
struct rb_root allocated_buffers;
size_t free_async_space;
struct binder_lru_page *pages;
size_t buffer_size;
uint32_t buffer_free;
int pid;
size_t pages_high;
};
#ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
void binder_selftest_alloc(struct binder_alloc *alloc);
#else
static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
#endif
enum lru_status binder_alloc_free_page(struct list_head *item,
struct list_lru_one *lru,
spinlock_t *lock, void *cb_arg);
extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
size_t data_size,
size_t offsets_size,
size_t extra_buffers_size,
int is_async,
int pid);
extern void binder_alloc_init(struct binder_alloc *alloc);
extern int binder_alloc_shrinker_init(void);
extern void binder_alloc_vma_close(struct binder_alloc *alloc);
extern struct binder_buffer *
binder_alloc_prepare_to_free(struct binder_alloc *alloc,
uintptr_t user_ptr);
extern void binder_alloc_free_buf(struct binder_alloc *alloc,
struct binder_buffer *buffer);
extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
struct vm_area_struct *vma);
extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
extern void binder_alloc_print_allocated(struct seq_file *m,
struct binder_alloc *alloc);
void binder_alloc_print_pages(struct seq_file *m,
struct binder_alloc *alloc);
/**
* binder_alloc_get_free_async_space() - get free space available for async
* @alloc: binder_alloc for this proc
*
* Return: the bytes remaining in the address-space for async transactions
*/
static inline size_t
binder_alloc_get_free_async_space(struct binder_alloc *alloc)
{
size_t free_async_space;
mutex_lock(&alloc->mutex);
free_async_space = alloc->free_async_space;
mutex_unlock(&alloc->mutex);
return free_async_space;
}
unsigned long
binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
struct binder_buffer *buffer,
binder_size_t buffer_offset,
const void __user *from,
size_t bytes);
int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
struct binder_buffer *buffer,
binder_size_t buffer_offset,
void *src,
size_t bytes);
int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
void *dest,
struct binder_buffer *buffer,
binder_size_t buffer_offset,
size_t bytes);
#endif /* _LINUX_BINDER_ALLOC_H */