1cb8444f31
commit cfd0d84ba28c18b531648c9d4a35ecca89ad9901 upstream. In 4.13, commit74310e06be
("android: binder: Move buffer out of area shared with user space") fixed a kernel structure visibility issue. As part of that patch, sizeof(void *) was used as the buffer size for 0-length data payloads so the driver could detect abusive clients sending 0-length asynchronous transactions to a server by enforcing limits on async_free_size. Unfortunately, on the "free" side, the accounting of async_free_space did not add the sizeof(void *) back. The result was that up to 8-bytes of async_free_space were leaked on every async transaction of 8-bytes or less. These small transactions are uncommon, so this accounting issue has gone undetected for several years. The fix is to use "buffer_size" (the allocated buffer size) instead of "size" (the logical buffer size) when updating the async_free_space during the free operation. These are the same except for this corner case of asynchronous transactions with payloads < 8 bytes. Fixes:74310e06be
("android: binder: Move buffer out of area shared with user space") Signed-off-by: Todd Kjos <tkjos@google.com> Cc: stable@vger.kernel.org # 4.14+ Link: https://lore.kernel.org/r/20211220190150.2107077-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1290 lines
35 KiB
C
1290 lines
35 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* binder_alloc.c
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*
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* Android IPC Subsystem
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*
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* Copyright (C) 2007-2017 Google, Inc.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/list.h>
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#include <linux/sched/mm.h>
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#include <linux/module.h>
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#include <linux/rtmutex.h>
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#include <linux/rbtree.h>
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#include <linux/seq_file.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/list_lru.h>
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#include <linux/ratelimit.h>
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#include <asm/cacheflush.h>
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#include <linux/uaccess.h>
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#include <linux/highmem.h>
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#include <linux/sizes.h>
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#include "binder_alloc.h"
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#include "binder_trace.h"
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struct list_lru binder_alloc_lru;
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static DEFINE_MUTEX(binder_alloc_mmap_lock);
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enum {
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BINDER_DEBUG_USER_ERROR = 1U << 0,
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BINDER_DEBUG_OPEN_CLOSE = 1U << 1,
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BINDER_DEBUG_BUFFER_ALLOC = 1U << 2,
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BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3,
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};
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static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
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module_param_named(debug_mask, binder_alloc_debug_mask,
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uint, 0644);
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#define binder_alloc_debug(mask, x...) \
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do { \
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if (binder_alloc_debug_mask & mask) \
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pr_info_ratelimited(x); \
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} while (0)
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static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
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{
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return list_entry(buffer->entry.next, struct binder_buffer, entry);
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}
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static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
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{
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return list_entry(buffer->entry.prev, struct binder_buffer, entry);
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}
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static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
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struct binder_buffer *buffer)
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{
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if (list_is_last(&buffer->entry, &alloc->buffers))
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return alloc->buffer + alloc->buffer_size - buffer->user_data;
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return binder_buffer_next(buffer)->user_data - buffer->user_data;
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}
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static void binder_insert_free_buffer(struct binder_alloc *alloc,
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struct binder_buffer *new_buffer)
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{
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struct rb_node **p = &alloc->free_buffers.rb_node;
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struct rb_node *parent = NULL;
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struct binder_buffer *buffer;
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size_t buffer_size;
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size_t new_buffer_size;
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BUG_ON(!new_buffer->free);
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new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
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binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
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"%d: add free buffer, size %zd, at %pK\n",
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alloc->pid, new_buffer_size, new_buffer);
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while (*p) {
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parent = *p;
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buffer = rb_entry(parent, struct binder_buffer, rb_node);
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BUG_ON(!buffer->free);
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buffer_size = binder_alloc_buffer_size(alloc, buffer);
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if (new_buffer_size < buffer_size)
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p = &parent->rb_left;
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else
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p = &parent->rb_right;
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}
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rb_link_node(&new_buffer->rb_node, parent, p);
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rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
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}
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static void binder_insert_allocated_buffer_locked(
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struct binder_alloc *alloc, struct binder_buffer *new_buffer)
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{
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struct rb_node **p = &alloc->allocated_buffers.rb_node;
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struct rb_node *parent = NULL;
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struct binder_buffer *buffer;
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BUG_ON(new_buffer->free);
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while (*p) {
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parent = *p;
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buffer = rb_entry(parent, struct binder_buffer, rb_node);
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BUG_ON(buffer->free);
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if (new_buffer->user_data < buffer->user_data)
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p = &parent->rb_left;
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else if (new_buffer->user_data > buffer->user_data)
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p = &parent->rb_right;
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else
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BUG();
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}
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rb_link_node(&new_buffer->rb_node, parent, p);
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rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
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}
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static struct binder_buffer *binder_alloc_prepare_to_free_locked(
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struct binder_alloc *alloc,
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uintptr_t user_ptr)
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{
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struct rb_node *n = alloc->allocated_buffers.rb_node;
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struct binder_buffer *buffer;
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void __user *uptr;
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uptr = (void __user *)user_ptr;
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while (n) {
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buffer = rb_entry(n, struct binder_buffer, rb_node);
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BUG_ON(buffer->free);
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if (uptr < buffer->user_data)
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n = n->rb_left;
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else if (uptr > buffer->user_data)
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n = n->rb_right;
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else {
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/*
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* Guard against user threads attempting to
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* free the buffer when in use by kernel or
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* after it's already been freed.
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*/
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if (!buffer->allow_user_free)
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return ERR_PTR(-EPERM);
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buffer->allow_user_free = 0;
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return buffer;
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}
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}
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return NULL;
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}
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/**
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* binder_alloc_prepare_to_free() - get buffer given user ptr
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* @alloc: binder_alloc for this proc
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* @user_ptr: User pointer to buffer data
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*
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* Validate userspace pointer to buffer data and return buffer corresponding to
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* that user pointer. Search the rb tree for buffer that matches user data
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* pointer.
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*
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* Return: Pointer to buffer or NULL
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*/
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struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
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uintptr_t user_ptr)
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{
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struct binder_buffer *buffer;
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mutex_lock(&alloc->mutex);
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buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
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mutex_unlock(&alloc->mutex);
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return buffer;
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}
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static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
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void __user *start, void __user *end)
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{
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void __user *page_addr;
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unsigned long user_page_addr;
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struct binder_lru_page *page;
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struct vm_area_struct *vma = NULL;
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struct mm_struct *mm = NULL;
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bool need_mm = false;
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binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
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"%d: %s pages %pK-%pK\n", alloc->pid,
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allocate ? "allocate" : "free", start, end);
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if (end <= start)
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return 0;
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trace_binder_update_page_range(alloc, allocate, start, end);
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if (allocate == 0)
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goto free_range;
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for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
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page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
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if (!page->page_ptr) {
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need_mm = true;
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break;
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}
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}
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if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
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mm = alloc->vma_vm_mm;
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if (mm) {
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mmap_read_lock(mm);
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vma = alloc->vma;
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}
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if (!vma && need_mm) {
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binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
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"%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
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alloc->pid);
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goto err_no_vma;
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}
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for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
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int ret;
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bool on_lru;
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size_t index;
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index = (page_addr - alloc->buffer) / PAGE_SIZE;
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page = &alloc->pages[index];
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if (page->page_ptr) {
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trace_binder_alloc_lru_start(alloc, index);
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on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
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WARN_ON(!on_lru);
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trace_binder_alloc_lru_end(alloc, index);
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continue;
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}
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if (WARN_ON(!vma))
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goto err_page_ptr_cleared;
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trace_binder_alloc_page_start(alloc, index);
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page->page_ptr = alloc_page(GFP_KERNEL |
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__GFP_HIGHMEM |
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__GFP_ZERO);
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if (!page->page_ptr) {
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pr_err("%d: binder_alloc_buf failed for page at %pK\n",
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alloc->pid, page_addr);
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goto err_alloc_page_failed;
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}
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page->alloc = alloc;
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INIT_LIST_HEAD(&page->lru);
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user_page_addr = (uintptr_t)page_addr;
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ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
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if (ret) {
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pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
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alloc->pid, user_page_addr);
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goto err_vm_insert_page_failed;
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}
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if (index + 1 > alloc->pages_high)
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alloc->pages_high = index + 1;
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trace_binder_alloc_page_end(alloc, index);
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}
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if (mm) {
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mmap_read_unlock(mm);
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mmput(mm);
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}
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return 0;
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free_range:
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for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
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bool ret;
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size_t index;
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index = (page_addr - alloc->buffer) / PAGE_SIZE;
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page = &alloc->pages[index];
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trace_binder_free_lru_start(alloc, index);
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ret = list_lru_add(&binder_alloc_lru, &page->lru);
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WARN_ON(!ret);
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trace_binder_free_lru_end(alloc, index);
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if (page_addr == start)
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break;
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continue;
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err_vm_insert_page_failed:
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__free_page(page->page_ptr);
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page->page_ptr = NULL;
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err_alloc_page_failed:
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err_page_ptr_cleared:
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if (page_addr == start)
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break;
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}
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err_no_vma:
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if (mm) {
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mmap_read_unlock(mm);
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mmput(mm);
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}
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return vma ? -ENOMEM : -ESRCH;
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}
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static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
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struct vm_area_struct *vma)
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{
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if (vma)
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alloc->vma_vm_mm = vma->vm_mm;
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/*
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* If we see alloc->vma is not NULL, buffer data structures set up
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* completely. Look at smp_rmb side binder_alloc_get_vma.
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* We also want to guarantee new alloc->vma_vm_mm is always visible
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* if alloc->vma is set.
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*/
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smp_wmb();
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alloc->vma = vma;
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}
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static inline struct vm_area_struct *binder_alloc_get_vma(
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struct binder_alloc *alloc)
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{
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struct vm_area_struct *vma = NULL;
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if (alloc->vma) {
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/* Look at description in binder_alloc_set_vma */
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smp_rmb();
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vma = alloc->vma;
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}
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return vma;
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}
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static void debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
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{
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/*
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* Find the amount and size of buffers allocated by the current caller;
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* The idea is that once we cross the threshold, whoever is responsible
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* for the low async space is likely to try to send another async txn,
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* and at some point we'll catch them in the act. This is more efficient
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* than keeping a map per pid.
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*/
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struct rb_node *n;
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struct binder_buffer *buffer;
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size_t total_alloc_size = 0;
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size_t num_buffers = 0;
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for (n = rb_first(&alloc->allocated_buffers); n != NULL;
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n = rb_next(n)) {
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buffer = rb_entry(n, struct binder_buffer, rb_node);
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if (buffer->pid != pid)
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continue;
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if (!buffer->async_transaction)
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continue;
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total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
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+ sizeof(struct binder_buffer);
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num_buffers++;
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}
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/*
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* Warn if this pid has more than 50 transactions, or more than 50% of
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* async space (which is 25% of total buffer size).
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*/
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if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
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binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
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"%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
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alloc->pid, pid, num_buffers, total_alloc_size);
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}
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}
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static struct binder_buffer *binder_alloc_new_buf_locked(
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struct binder_alloc *alloc,
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size_t data_size,
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size_t offsets_size,
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size_t extra_buffers_size,
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int is_async,
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int pid)
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{
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struct rb_node *n = alloc->free_buffers.rb_node;
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struct binder_buffer *buffer;
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size_t buffer_size;
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struct rb_node *best_fit = NULL;
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void __user *has_page_addr;
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void __user *end_page_addr;
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size_t size, data_offsets_size;
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int ret;
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if (!binder_alloc_get_vma(alloc)) {
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binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
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"%d: binder_alloc_buf, no vma\n",
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alloc->pid);
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return ERR_PTR(-ESRCH);
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}
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data_offsets_size = ALIGN(data_size, sizeof(void *)) +
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ALIGN(offsets_size, sizeof(void *));
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if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
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binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
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"%d: got transaction with invalid size %zd-%zd\n",
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alloc->pid, data_size, offsets_size);
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return ERR_PTR(-EINVAL);
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}
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size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
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if (size < data_offsets_size || size < extra_buffers_size) {
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binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
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"%d: got transaction with invalid extra_buffers_size %zd\n",
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alloc->pid, extra_buffers_size);
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return ERR_PTR(-EINVAL);
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}
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if (is_async &&
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alloc->free_async_space < size + sizeof(struct binder_buffer)) {
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binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
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"%d: binder_alloc_buf size %zd failed, no async space left\n",
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alloc->pid, size);
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return ERR_PTR(-ENOSPC);
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}
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/* Pad 0-size buffers so they get assigned unique addresses */
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size = max(size, sizeof(void *));
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while (n) {
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buffer = rb_entry(n, struct binder_buffer, rb_node);
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BUG_ON(!buffer->free);
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buffer_size = binder_alloc_buffer_size(alloc, buffer);
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if (size < buffer_size) {
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best_fit = n;
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n = n->rb_left;
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} else if (size > buffer_size)
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n = n->rb_right;
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else {
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best_fit = n;
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break;
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}
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}
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if (best_fit == NULL) {
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size_t allocated_buffers = 0;
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size_t largest_alloc_size = 0;
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size_t total_alloc_size = 0;
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size_t free_buffers = 0;
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size_t largest_free_size = 0;
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size_t total_free_size = 0;
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for (n = rb_first(&alloc->allocated_buffers); n != NULL;
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n = rb_next(n)) {
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buffer = rb_entry(n, struct binder_buffer, rb_node);
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buffer_size = binder_alloc_buffer_size(alloc, buffer);
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allocated_buffers++;
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total_alloc_size += buffer_size;
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if (buffer_size > largest_alloc_size)
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largest_alloc_size = buffer_size;
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}
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for (n = rb_first(&alloc->free_buffers); n != NULL;
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n = rb_next(n)) {
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buffer = rb_entry(n, struct binder_buffer, rb_node);
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buffer_size = binder_alloc_buffer_size(alloc, buffer);
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free_buffers++;
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total_free_size += buffer_size;
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if (buffer_size > largest_free_size)
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largest_free_size = buffer_size;
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}
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binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
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"%d: binder_alloc_buf size %zd failed, no address space\n",
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alloc->pid, size);
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binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
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"allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
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total_alloc_size, allocated_buffers,
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largest_alloc_size, total_free_size,
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free_buffers, largest_free_size);
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return ERR_PTR(-ENOSPC);
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}
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if (n == NULL) {
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buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
|
|
buffer_size = binder_alloc_buffer_size(alloc, buffer);
|
|
}
|
|
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
|
|
alloc->pid, size, buffer, buffer_size);
|
|
|
|
has_page_addr = (void __user *)
|
|
(((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
|
|
WARN_ON(n && buffer_size != size);
|
|
end_page_addr =
|
|
(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
|
|
if (end_page_addr > has_page_addr)
|
|
end_page_addr = has_page_addr;
|
|
ret = binder_update_page_range(alloc, 1, (void __user *)
|
|
PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
if (buffer_size != size) {
|
|
struct binder_buffer *new_buffer;
|
|
|
|
new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
|
|
if (!new_buffer) {
|
|
pr_err("%s: %d failed to alloc new buffer struct\n",
|
|
__func__, alloc->pid);
|
|
goto err_alloc_buf_struct_failed;
|
|
}
|
|
new_buffer->user_data = (u8 __user *)buffer->user_data + size;
|
|
list_add(&new_buffer->entry, &buffer->entry);
|
|
new_buffer->free = 1;
|
|
binder_insert_free_buffer(alloc, new_buffer);
|
|
}
|
|
|
|
rb_erase(best_fit, &alloc->free_buffers);
|
|
buffer->free = 0;
|
|
buffer->allow_user_free = 0;
|
|
binder_insert_allocated_buffer_locked(alloc, buffer);
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: binder_alloc_buf size %zd got %pK\n",
|
|
alloc->pid, size, buffer);
|
|
buffer->data_size = data_size;
|
|
buffer->offsets_size = offsets_size;
|
|
buffer->async_transaction = is_async;
|
|
buffer->extra_buffers_size = extra_buffers_size;
|
|
buffer->pid = pid;
|
|
if (is_async) {
|
|
alloc->free_async_space -= size + sizeof(struct binder_buffer);
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
|
|
"%d: binder_alloc_buf size %zd async free %zd\n",
|
|
alloc->pid, size, alloc->free_async_space);
|
|
if (alloc->free_async_space < alloc->buffer_size / 10) {
|
|
/*
|
|
* Start detecting spammers once we have less than 20%
|
|
* of async space left (which is less than 10% of total
|
|
* buffer size).
|
|
*/
|
|
debug_low_async_space_locked(alloc, pid);
|
|
}
|
|
}
|
|
return buffer;
|
|
|
|
err_alloc_buf_struct_failed:
|
|
binder_update_page_range(alloc, 0, (void __user *)
|
|
PAGE_ALIGN((uintptr_t)buffer->user_data),
|
|
end_page_addr);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_new_buf() - Allocate a new binder buffer
|
|
* @alloc: binder_alloc for this proc
|
|
* @data_size: size of user data buffer
|
|
* @offsets_size: user specified buffer offset
|
|
* @extra_buffers_size: size of extra space for meta-data (eg, security context)
|
|
* @is_async: buffer for async transaction
|
|
* @pid: pid to attribute allocation to (used for debugging)
|
|
*
|
|
* Allocate a new buffer given the requested sizes. Returns
|
|
* the kernel version of the buffer pointer. The size allocated
|
|
* is the sum of the three given sizes (each rounded up to
|
|
* pointer-sized boundary)
|
|
*
|
|
* Return: The allocated buffer or %NULL if error
|
|
*/
|
|
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)
|
|
{
|
|
struct binder_buffer *buffer;
|
|
|
|
mutex_lock(&alloc->mutex);
|
|
buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
|
|
extra_buffers_size, is_async, pid);
|
|
mutex_unlock(&alloc->mutex);
|
|
return buffer;
|
|
}
|
|
|
|
static void __user *buffer_start_page(struct binder_buffer *buffer)
|
|
{
|
|
return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
|
|
}
|
|
|
|
static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
|
|
{
|
|
return (void __user *)
|
|
(((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
|
|
}
|
|
|
|
static void binder_delete_free_buffer(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer)
|
|
{
|
|
struct binder_buffer *prev, *next = NULL;
|
|
bool to_free = true;
|
|
|
|
BUG_ON(alloc->buffers.next == &buffer->entry);
|
|
prev = binder_buffer_prev(buffer);
|
|
BUG_ON(!prev->free);
|
|
if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
|
|
to_free = false;
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: merge free, buffer %pK share page with %pK\n",
|
|
alloc->pid, buffer->user_data,
|
|
prev->user_data);
|
|
}
|
|
|
|
if (!list_is_last(&buffer->entry, &alloc->buffers)) {
|
|
next = binder_buffer_next(buffer);
|
|
if (buffer_start_page(next) == buffer_start_page(buffer)) {
|
|
to_free = false;
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: merge free, buffer %pK share page with %pK\n",
|
|
alloc->pid,
|
|
buffer->user_data,
|
|
next->user_data);
|
|
}
|
|
}
|
|
|
|
if (PAGE_ALIGNED(buffer->user_data)) {
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: merge free, buffer start %pK is page aligned\n",
|
|
alloc->pid, buffer->user_data);
|
|
to_free = false;
|
|
}
|
|
|
|
if (to_free) {
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: merge free, buffer %pK do not share page with %pK or %pK\n",
|
|
alloc->pid, buffer->user_data,
|
|
prev->user_data,
|
|
next ? next->user_data : NULL);
|
|
binder_update_page_range(alloc, 0, buffer_start_page(buffer),
|
|
buffer_start_page(buffer) + PAGE_SIZE);
|
|
}
|
|
list_del(&buffer->entry);
|
|
kfree(buffer);
|
|
}
|
|
|
|
static void binder_free_buf_locked(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer)
|
|
{
|
|
size_t size, buffer_size;
|
|
|
|
buffer_size = binder_alloc_buffer_size(alloc, buffer);
|
|
|
|
size = ALIGN(buffer->data_size, sizeof(void *)) +
|
|
ALIGN(buffer->offsets_size, sizeof(void *)) +
|
|
ALIGN(buffer->extra_buffers_size, sizeof(void *));
|
|
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%d: binder_free_buf %pK size %zd buffer_size %zd\n",
|
|
alloc->pid, buffer, size, buffer_size);
|
|
|
|
BUG_ON(buffer->free);
|
|
BUG_ON(size > buffer_size);
|
|
BUG_ON(buffer->transaction != NULL);
|
|
BUG_ON(buffer->user_data < alloc->buffer);
|
|
BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
|
|
|
|
if (buffer->async_transaction) {
|
|
alloc->free_async_space += buffer_size + sizeof(struct binder_buffer);
|
|
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
|
|
"%d: binder_free_buf size %zd async free %zd\n",
|
|
alloc->pid, size, alloc->free_async_space);
|
|
}
|
|
|
|
binder_update_page_range(alloc, 0,
|
|
(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
|
|
(void __user *)(((uintptr_t)
|
|
buffer->user_data + buffer_size) & PAGE_MASK));
|
|
|
|
rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
|
|
buffer->free = 1;
|
|
if (!list_is_last(&buffer->entry, &alloc->buffers)) {
|
|
struct binder_buffer *next = binder_buffer_next(buffer);
|
|
|
|
if (next->free) {
|
|
rb_erase(&next->rb_node, &alloc->free_buffers);
|
|
binder_delete_free_buffer(alloc, next);
|
|
}
|
|
}
|
|
if (alloc->buffers.next != &buffer->entry) {
|
|
struct binder_buffer *prev = binder_buffer_prev(buffer);
|
|
|
|
if (prev->free) {
|
|
binder_delete_free_buffer(alloc, buffer);
|
|
rb_erase(&prev->rb_node, &alloc->free_buffers);
|
|
buffer = prev;
|
|
}
|
|
}
|
|
binder_insert_free_buffer(alloc, buffer);
|
|
}
|
|
|
|
static void binder_alloc_clear_buf(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer);
|
|
/**
|
|
* binder_alloc_free_buf() - free a binder buffer
|
|
* @alloc: binder_alloc for this proc
|
|
* @buffer: kernel pointer to buffer
|
|
*
|
|
* Free the buffer allocated via binder_alloc_new_buf()
|
|
*/
|
|
void binder_alloc_free_buf(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer)
|
|
{
|
|
/*
|
|
* We could eliminate the call to binder_alloc_clear_buf()
|
|
* from binder_alloc_deferred_release() by moving this to
|
|
* binder_alloc_free_buf_locked(). However, that could
|
|
* increase contention for the alloc mutex if clear_on_free
|
|
* is used frequently for large buffers. The mutex is not
|
|
* needed for correctness here.
|
|
*/
|
|
if (buffer->clear_on_free) {
|
|
binder_alloc_clear_buf(alloc, buffer);
|
|
buffer->clear_on_free = false;
|
|
}
|
|
mutex_lock(&alloc->mutex);
|
|
binder_free_buf_locked(alloc, buffer);
|
|
mutex_unlock(&alloc->mutex);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_mmap_handler() - map virtual address space for proc
|
|
* @alloc: alloc structure for this proc
|
|
* @vma: vma passed to mmap()
|
|
*
|
|
* Called by binder_mmap() to initialize the space specified in
|
|
* vma for allocating binder buffers
|
|
*
|
|
* Return:
|
|
* 0 = success
|
|
* -EBUSY = address space already mapped
|
|
* -ENOMEM = failed to map memory to given address space
|
|
*/
|
|
int binder_alloc_mmap_handler(struct binder_alloc *alloc,
|
|
struct vm_area_struct *vma)
|
|
{
|
|
int ret;
|
|
const char *failure_string;
|
|
struct binder_buffer *buffer;
|
|
|
|
mutex_lock(&binder_alloc_mmap_lock);
|
|
if (alloc->buffer_size) {
|
|
ret = -EBUSY;
|
|
failure_string = "already mapped";
|
|
goto err_already_mapped;
|
|
}
|
|
alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
|
|
SZ_4M);
|
|
mutex_unlock(&binder_alloc_mmap_lock);
|
|
|
|
alloc->buffer = (void __user *)vma->vm_start;
|
|
|
|
alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
|
|
sizeof(alloc->pages[0]),
|
|
GFP_KERNEL);
|
|
if (alloc->pages == NULL) {
|
|
ret = -ENOMEM;
|
|
failure_string = "alloc page array";
|
|
goto err_alloc_pages_failed;
|
|
}
|
|
|
|
buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
|
|
if (!buffer) {
|
|
ret = -ENOMEM;
|
|
failure_string = "alloc buffer struct";
|
|
goto err_alloc_buf_struct_failed;
|
|
}
|
|
|
|
buffer->user_data = alloc->buffer;
|
|
list_add(&buffer->entry, &alloc->buffers);
|
|
buffer->free = 1;
|
|
binder_insert_free_buffer(alloc, buffer);
|
|
alloc->free_async_space = alloc->buffer_size / 2;
|
|
binder_alloc_set_vma(alloc, vma);
|
|
mmgrab(alloc->vma_vm_mm);
|
|
|
|
return 0;
|
|
|
|
err_alloc_buf_struct_failed:
|
|
kfree(alloc->pages);
|
|
alloc->pages = NULL;
|
|
err_alloc_pages_failed:
|
|
alloc->buffer = NULL;
|
|
mutex_lock(&binder_alloc_mmap_lock);
|
|
alloc->buffer_size = 0;
|
|
err_already_mapped:
|
|
mutex_unlock(&binder_alloc_mmap_lock);
|
|
binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
|
|
"%s: %d %lx-%lx %s failed %d\n", __func__,
|
|
alloc->pid, vma->vm_start, vma->vm_end,
|
|
failure_string, ret);
|
|
return ret;
|
|
}
|
|
|
|
|
|
void binder_alloc_deferred_release(struct binder_alloc *alloc)
|
|
{
|
|
struct rb_node *n;
|
|
int buffers, page_count;
|
|
struct binder_buffer *buffer;
|
|
|
|
buffers = 0;
|
|
mutex_lock(&alloc->mutex);
|
|
BUG_ON(alloc->vma);
|
|
|
|
while ((n = rb_first(&alloc->allocated_buffers))) {
|
|
buffer = rb_entry(n, struct binder_buffer, rb_node);
|
|
|
|
/* Transaction should already have been freed */
|
|
BUG_ON(buffer->transaction);
|
|
|
|
if (buffer->clear_on_free) {
|
|
binder_alloc_clear_buf(alloc, buffer);
|
|
buffer->clear_on_free = false;
|
|
}
|
|
binder_free_buf_locked(alloc, buffer);
|
|
buffers++;
|
|
}
|
|
|
|
while (!list_empty(&alloc->buffers)) {
|
|
buffer = list_first_entry(&alloc->buffers,
|
|
struct binder_buffer, entry);
|
|
WARN_ON(!buffer->free);
|
|
|
|
list_del(&buffer->entry);
|
|
WARN_ON_ONCE(!list_empty(&alloc->buffers));
|
|
kfree(buffer);
|
|
}
|
|
|
|
page_count = 0;
|
|
if (alloc->pages) {
|
|
int i;
|
|
|
|
for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
|
|
void __user *page_addr;
|
|
bool on_lru;
|
|
|
|
if (!alloc->pages[i].page_ptr)
|
|
continue;
|
|
|
|
on_lru = list_lru_del(&binder_alloc_lru,
|
|
&alloc->pages[i].lru);
|
|
page_addr = alloc->buffer + i * PAGE_SIZE;
|
|
binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
|
|
"%s: %d: page %d at %pK %s\n",
|
|
__func__, alloc->pid, i, page_addr,
|
|
on_lru ? "on lru" : "active");
|
|
__free_page(alloc->pages[i].page_ptr);
|
|
page_count++;
|
|
}
|
|
kfree(alloc->pages);
|
|
}
|
|
mutex_unlock(&alloc->mutex);
|
|
if (alloc->vma_vm_mm)
|
|
mmdrop(alloc->vma_vm_mm);
|
|
|
|
binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
|
|
"%s: %d buffers %d, pages %d\n",
|
|
__func__, alloc->pid, buffers, page_count);
|
|
}
|
|
|
|
static void print_binder_buffer(struct seq_file *m, const char *prefix,
|
|
struct binder_buffer *buffer)
|
|
{
|
|
seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
|
|
prefix, buffer->debug_id, buffer->user_data,
|
|
buffer->data_size, buffer->offsets_size,
|
|
buffer->extra_buffers_size,
|
|
buffer->transaction ? "active" : "delivered");
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_print_allocated() - print buffer info
|
|
* @m: seq_file for output via seq_printf()
|
|
* @alloc: binder_alloc for this proc
|
|
*
|
|
* Prints information about every buffer associated with
|
|
* the binder_alloc state to the given seq_file
|
|
*/
|
|
void binder_alloc_print_allocated(struct seq_file *m,
|
|
struct binder_alloc *alloc)
|
|
{
|
|
struct rb_node *n;
|
|
|
|
mutex_lock(&alloc->mutex);
|
|
for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
|
|
print_binder_buffer(m, " buffer",
|
|
rb_entry(n, struct binder_buffer, rb_node));
|
|
mutex_unlock(&alloc->mutex);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_print_pages() - print page usage
|
|
* @m: seq_file for output via seq_printf()
|
|
* @alloc: binder_alloc for this proc
|
|
*/
|
|
void binder_alloc_print_pages(struct seq_file *m,
|
|
struct binder_alloc *alloc)
|
|
{
|
|
struct binder_lru_page *page;
|
|
int i;
|
|
int active = 0;
|
|
int lru = 0;
|
|
int free = 0;
|
|
|
|
mutex_lock(&alloc->mutex);
|
|
/*
|
|
* Make sure the binder_alloc is fully initialized, otherwise we might
|
|
* read inconsistent state.
|
|
*/
|
|
if (binder_alloc_get_vma(alloc) != NULL) {
|
|
for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
|
|
page = &alloc->pages[i];
|
|
if (!page->page_ptr)
|
|
free++;
|
|
else if (list_empty(&page->lru))
|
|
active++;
|
|
else
|
|
lru++;
|
|
}
|
|
}
|
|
mutex_unlock(&alloc->mutex);
|
|
seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
|
|
seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_get_allocated_count() - return count of buffers
|
|
* @alloc: binder_alloc for this proc
|
|
*
|
|
* Return: count of allocated buffers
|
|
*/
|
|
int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
|
|
{
|
|
struct rb_node *n;
|
|
int count = 0;
|
|
|
|
mutex_lock(&alloc->mutex);
|
|
for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
|
|
count++;
|
|
mutex_unlock(&alloc->mutex);
|
|
return count;
|
|
}
|
|
|
|
|
|
/**
|
|
* binder_alloc_vma_close() - invalidate address space
|
|
* @alloc: binder_alloc for this proc
|
|
*
|
|
* Called from binder_vma_close() when releasing address space.
|
|
* Clears alloc->vma to prevent new incoming transactions from
|
|
* allocating more buffers.
|
|
*/
|
|
void binder_alloc_vma_close(struct binder_alloc *alloc)
|
|
{
|
|
binder_alloc_set_vma(alloc, NULL);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_free_page() - shrinker callback to free pages
|
|
* @item: item to free
|
|
* @lock: lock protecting the item
|
|
* @cb_arg: callback argument
|
|
*
|
|
* Called from list_lru_walk() in binder_shrink_scan() to free
|
|
* up pages when the system is under memory pressure.
|
|
*/
|
|
enum lru_status binder_alloc_free_page(struct list_head *item,
|
|
struct list_lru_one *lru,
|
|
spinlock_t *lock,
|
|
void *cb_arg)
|
|
__must_hold(lock)
|
|
{
|
|
struct mm_struct *mm = NULL;
|
|
struct binder_lru_page *page = container_of(item,
|
|
struct binder_lru_page,
|
|
lru);
|
|
struct binder_alloc *alloc;
|
|
uintptr_t page_addr;
|
|
size_t index;
|
|
struct vm_area_struct *vma;
|
|
|
|
alloc = page->alloc;
|
|
if (!mutex_trylock(&alloc->mutex))
|
|
goto err_get_alloc_mutex_failed;
|
|
|
|
if (!page->page_ptr)
|
|
goto err_page_already_freed;
|
|
|
|
index = page - alloc->pages;
|
|
page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
|
|
|
|
mm = alloc->vma_vm_mm;
|
|
if (!mmget_not_zero(mm))
|
|
goto err_mmget;
|
|
if (!mmap_read_trylock(mm))
|
|
goto err_mmap_read_lock_failed;
|
|
vma = binder_alloc_get_vma(alloc);
|
|
|
|
list_lru_isolate(lru, item);
|
|
spin_unlock(lock);
|
|
|
|
if (vma) {
|
|
trace_binder_unmap_user_start(alloc, index);
|
|
|
|
zap_page_range(vma, page_addr, PAGE_SIZE);
|
|
|
|
trace_binder_unmap_user_end(alloc, index);
|
|
}
|
|
mmap_read_unlock(mm);
|
|
mmput_async(mm);
|
|
|
|
trace_binder_unmap_kernel_start(alloc, index);
|
|
|
|
__free_page(page->page_ptr);
|
|
page->page_ptr = NULL;
|
|
|
|
trace_binder_unmap_kernel_end(alloc, index);
|
|
|
|
spin_lock(lock);
|
|
mutex_unlock(&alloc->mutex);
|
|
return LRU_REMOVED_RETRY;
|
|
|
|
err_mmap_read_lock_failed:
|
|
mmput_async(mm);
|
|
err_mmget:
|
|
err_page_already_freed:
|
|
mutex_unlock(&alloc->mutex);
|
|
err_get_alloc_mutex_failed:
|
|
return LRU_SKIP;
|
|
}
|
|
|
|
static unsigned long
|
|
binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
|
|
{
|
|
unsigned long ret = list_lru_count(&binder_alloc_lru);
|
|
return ret;
|
|
}
|
|
|
|
static unsigned long
|
|
binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
|
|
{
|
|
unsigned long ret;
|
|
|
|
ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
|
|
NULL, sc->nr_to_scan);
|
|
return ret;
|
|
}
|
|
|
|
static struct shrinker binder_shrinker = {
|
|
.count_objects = binder_shrink_count,
|
|
.scan_objects = binder_shrink_scan,
|
|
.seeks = DEFAULT_SEEKS,
|
|
};
|
|
|
|
/**
|
|
* binder_alloc_init() - called by binder_open() for per-proc initialization
|
|
* @alloc: binder_alloc for this proc
|
|
*
|
|
* Called from binder_open() to initialize binder_alloc fields for
|
|
* new binder proc
|
|
*/
|
|
void binder_alloc_init(struct binder_alloc *alloc)
|
|
{
|
|
alloc->pid = current->group_leader->pid;
|
|
mutex_init(&alloc->mutex);
|
|
INIT_LIST_HEAD(&alloc->buffers);
|
|
}
|
|
|
|
int binder_alloc_shrinker_init(void)
|
|
{
|
|
int ret = list_lru_init(&binder_alloc_lru);
|
|
|
|
if (ret == 0) {
|
|
ret = register_shrinker(&binder_shrinker);
|
|
if (ret)
|
|
list_lru_destroy(&binder_alloc_lru);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* check_buffer() - verify that buffer/offset is safe to access
|
|
* @alloc: binder_alloc for this proc
|
|
* @buffer: binder buffer to be accessed
|
|
* @offset: offset into @buffer data
|
|
* @bytes: bytes to access from offset
|
|
*
|
|
* Check that the @offset/@bytes are within the size of the given
|
|
* @buffer and that the buffer is currently active and not freeable.
|
|
* Offsets must also be multiples of sizeof(u32). The kernel is
|
|
* allowed to touch the buffer in two cases:
|
|
*
|
|
* 1) when the buffer is being created:
|
|
* (buffer->free == 0 && buffer->allow_user_free == 0)
|
|
* 2) when the buffer is being torn down:
|
|
* (buffer->free == 0 && buffer->transaction == NULL).
|
|
*
|
|
* Return: true if the buffer is safe to access
|
|
*/
|
|
static inline bool check_buffer(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer,
|
|
binder_size_t offset, size_t bytes)
|
|
{
|
|
size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
|
|
|
|
return buffer_size >= bytes &&
|
|
offset <= buffer_size - bytes &&
|
|
IS_ALIGNED(offset, sizeof(u32)) &&
|
|
!buffer->free &&
|
|
(!buffer->allow_user_free || !buffer->transaction);
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_get_page() - get kernel pointer for given buffer offset
|
|
* @alloc: binder_alloc for this proc
|
|
* @buffer: binder buffer to be accessed
|
|
* @buffer_offset: offset into @buffer data
|
|
* @pgoffp: address to copy final page offset to
|
|
*
|
|
* Lookup the struct page corresponding to the address
|
|
* at @buffer_offset into @buffer->user_data. If @pgoffp is not
|
|
* NULL, the byte-offset into the page is written there.
|
|
*
|
|
* The caller is responsible to ensure that the offset points
|
|
* to a valid address within the @buffer and that @buffer is
|
|
* not freeable by the user. Since it can't be freed, we are
|
|
* guaranteed that the corresponding elements of @alloc->pages[]
|
|
* cannot change.
|
|
*
|
|
* Return: struct page
|
|
*/
|
|
static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer,
|
|
binder_size_t buffer_offset,
|
|
pgoff_t *pgoffp)
|
|
{
|
|
binder_size_t buffer_space_offset = buffer_offset +
|
|
(buffer->user_data - alloc->buffer);
|
|
pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
|
|
size_t index = buffer_space_offset >> PAGE_SHIFT;
|
|
struct binder_lru_page *lru_page;
|
|
|
|
lru_page = &alloc->pages[index];
|
|
*pgoffp = pgoff;
|
|
return lru_page->page_ptr;
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_clear_buf() - zero out buffer
|
|
* @alloc: binder_alloc for this proc
|
|
* @buffer: binder buffer to be cleared
|
|
*
|
|
* memset the given buffer to 0
|
|
*/
|
|
static void binder_alloc_clear_buf(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer)
|
|
{
|
|
size_t bytes = binder_alloc_buffer_size(alloc, buffer);
|
|
binder_size_t buffer_offset = 0;
|
|
|
|
while (bytes) {
|
|
unsigned long size;
|
|
struct page *page;
|
|
pgoff_t pgoff;
|
|
void *kptr;
|
|
|
|
page = binder_alloc_get_page(alloc, buffer,
|
|
buffer_offset, &pgoff);
|
|
size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
|
|
kptr = kmap(page) + pgoff;
|
|
memset(kptr, 0, size);
|
|
kunmap(page);
|
|
bytes -= size;
|
|
buffer_offset += size;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* binder_alloc_copy_user_to_buffer() - copy src user to tgt user
|
|
* @alloc: binder_alloc for this proc
|
|
* @buffer: binder buffer to be accessed
|
|
* @buffer_offset: offset into @buffer data
|
|
* @from: userspace pointer to source buffer
|
|
* @bytes: bytes to copy
|
|
*
|
|
* Copy bytes from source userspace to target buffer.
|
|
*
|
|
* Return: bytes remaining to be copied
|
|
*/
|
|
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)
|
|
{
|
|
if (!check_buffer(alloc, buffer, buffer_offset, bytes))
|
|
return bytes;
|
|
|
|
while (bytes) {
|
|
unsigned long size;
|
|
unsigned long ret;
|
|
struct page *page;
|
|
pgoff_t pgoff;
|
|
void *kptr;
|
|
|
|
page = binder_alloc_get_page(alloc, buffer,
|
|
buffer_offset, &pgoff);
|
|
size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
|
|
kptr = kmap(page) + pgoff;
|
|
ret = copy_from_user(kptr, from, size);
|
|
kunmap(page);
|
|
if (ret)
|
|
return bytes - size + ret;
|
|
bytes -= size;
|
|
from += size;
|
|
buffer_offset += size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
|
|
bool to_buffer,
|
|
struct binder_buffer *buffer,
|
|
binder_size_t buffer_offset,
|
|
void *ptr,
|
|
size_t bytes)
|
|
{
|
|
/* All copies must be 32-bit aligned and 32-bit size */
|
|
if (!check_buffer(alloc, buffer, buffer_offset, bytes))
|
|
return -EINVAL;
|
|
|
|
while (bytes) {
|
|
unsigned long size;
|
|
struct page *page;
|
|
pgoff_t pgoff;
|
|
void *tmpptr;
|
|
void *base_ptr;
|
|
|
|
page = binder_alloc_get_page(alloc, buffer,
|
|
buffer_offset, &pgoff);
|
|
size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
|
|
base_ptr = kmap_atomic(page);
|
|
tmpptr = base_ptr + pgoff;
|
|
if (to_buffer)
|
|
memcpy(tmpptr, ptr, size);
|
|
else
|
|
memcpy(ptr, tmpptr, size);
|
|
/*
|
|
* kunmap_atomic() takes care of flushing the cache
|
|
* if this device has VIVT cache arch
|
|
*/
|
|
kunmap_atomic(base_ptr);
|
|
bytes -= size;
|
|
pgoff = 0;
|
|
ptr = ptr + size;
|
|
buffer_offset += size;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
|
|
struct binder_buffer *buffer,
|
|
binder_size_t buffer_offset,
|
|
void *src,
|
|
size_t bytes)
|
|
{
|
|
return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
|
|
src, 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)
|
|
{
|
|
return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
|
|
dest, bytes);
|
|
}
|
|
|