ALIGN(tr->data_size, sizeof(void *)));
offp = off_start;
- if (copy_from_user(t->buffer->data, (const void __user *)(uintptr_t)
- tr->data.ptr.buffer, tr->data_size)) {
+ if (binder_alloc_copy_user_to_buffer(
+ &target_proc->alloc,
+ t->buffer, 0,
+ (const void __user *)
+ (uintptr_t)tr->data.ptr.buffer,
+ tr->data_size)) {
binder_user_error("%d:%d got transaction with invalid data ptr\n",
proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
return_error_line = __LINE__;
goto err_copy_data_failed;
}
- if (copy_from_user(offp, (const void __user *)(uintptr_t)
- tr->data.ptr.offsets, tr->offsets_size)) {
+ if (binder_alloc_copy_user_to_buffer(
+ &target_proc->alloc,
+ t->buffer,
+ ALIGN(tr->data_size, sizeof(void *)),
+ (const void __user *)
+ (uintptr_t)tr->data.ptr.offsets,
+ tr->offsets_size)) {
binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
proc->pid, thread->pid);
return_error = BR_FAILED_REPLY;
struct binder_buffer_object *bp =
to_binder_buffer_object(hdr);
size_t buf_left = sg_buf_end - sg_bufp;
+ binder_size_t sg_buf_offset = (uintptr_t)sg_bufp -
+ (uintptr_t)t->buffer->data;
if (bp->length > buf_left) {
binder_user_error("%d:%d got transaction with too large buffer\n",
return_error_line = __LINE__;
goto err_bad_offset;
}
- if (copy_from_user(sg_bufp,
- (const void __user *)(uintptr_t)
- bp->buffer, bp->length)) {
+ if (binder_alloc_copy_user_to_buffer(
+ &target_proc->alloc,
+ t->buffer,
+ sg_buf_offset,
+ (const void __user *)
+ (uintptr_t)bp->buffer,
+ bp->length)) {
binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
proc->pid, thread->pid);
return_error_param = -EFAULT;
#include <linux/list_lru.h>
#include <linux/ratelimit.h>
#include <asm/cacheflush.h>
+#include <linux/uaccess.h>
+#include <linux/highmem.h>
#include "binder_alloc.h"
#include "binder_trace.h"
}
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->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->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_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;
+}
projects / openwrt / staging / blogic.git / commitdiff