Commit 48a2d422 authored by Roman Kiryanov's avatar Roman Kiryanov Committed by Greg Kroah-Hartman
Browse files

platform: goldfish: pipe: Prevent memory corruption from several threads... 


platform: goldfish: pipe: Prevent memory corruption from several threads writing to the same variable

Move the "pages" buffer into "struct goldfish_pipe". Since we are
locking the mutex on the pipe in transfer_max_buffers, other threads
willnot be able to write into it, but other pipe instances could be
served because they have its own buffer.

Signed-off-by: default avatarRoman Kiryanov <rkir@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9b9a4a3f

drivers/platform/goldfish/goldfish_pipe.c

+14 −10
Original line number Diff line number Diff line
@@ -163,6 +163,9 @@ struct goldfish_pipe { 


	/* Pointer to the parent goldfish_pipe_dev instance */

	struct goldfish_pipe_dev *dev;



	/* A buffer of pages, too large to fit into a stack frame */

	struct page *pages[MAX_BUFFERS_PER_COMMAND];

};



/* The global driver data. Holds a reference to the i/o page used to
@@ -340,21 +343,23 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe, 
				s32 *consumed_size,

				int *status)

{

	static struct page *pages[MAX_BUFFERS_PER_COMMAND];

	unsigned long first_page = address & PAGE_MASK;

	unsigned int iter_last_page_size;

	int pages_count = pin_user_pages(first_page, last_page,

					 last_page_size, is_write,

					 pages, &iter_last_page_size);



	if (pages_count < 0)

		return pages_count;

	int pages_count;



	/* Serialize access to the pipe command buffers */

	if (mutex_lock_interruptible(&pipe->lock))

		return -ERESTARTSYS;



	populate_rw_params(pages, pages_count, address, address_end,

	pages_count = pin_user_pages(first_page, last_page,

				     last_page_size, is_write,

				     pipe->pages, &iter_last_page_size);

	if (pages_count < 0) {

		mutex_unlock(&pipe->lock);

		return pages_count;

	}



	populate_rw_params(pipe->pages, pages_count, address, address_end,

			   first_page, last_page, iter_last_page_size, is_write,

			   pipe->command_buffer);
@@ -364,10 +369,9 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe, 


	*consumed_size = pipe->command_buffer->rw_params.consumed_size;



	release_user_pages(pages, pages_count, is_write, *consumed_size);

	release_user_pages(pipe->pages, pages_count, is_write, *consumed_size);



	mutex_unlock(&pipe->lock);



	return 0;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE