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

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
...@@ -163,6 +163,9 @@ struct goldfish_pipe { ...@@ -163,6 +163,9 @@ struct goldfish_pipe {
/* Pointer to the parent goldfish_pipe_dev instance */ /* Pointer to the parent goldfish_pipe_dev instance */
struct goldfish_pipe_dev *dev; 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 /* 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, ...@@ -340,21 +343,23 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe,
s32 *consumed_size, s32 *consumed_size,
int *status) int *status)
{ {
static struct page *pages[MAX_BUFFERS_PER_COMMAND];
unsigned long first_page = address & PAGE_MASK; unsigned long first_page = address & PAGE_MASK;
unsigned int iter_last_page_size; unsigned int iter_last_page_size;
int pages_count = pin_user_pages(first_page, last_page, int pages_count;
last_page_size, is_write,
pages, &iter_last_page_size);
if (pages_count < 0)
return pages_count;
/* Serialize access to the pipe command buffers */ /* Serialize access to the pipe command buffers */
if (mutex_lock_interruptible(&pipe->lock)) if (mutex_lock_interruptible(&pipe->lock))
return -ERESTARTSYS; 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, first_page, last_page, iter_last_page_size, is_write,
pipe->command_buffer); pipe->command_buffer);
...@@ -364,10 +369,9 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe, ...@@ -364,10 +369,9 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe,
*consumed_size = pipe->command_buffer->rw_params.consumed_size; *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); mutex_unlock(&pipe->lock);
return 0; return 0;
} }
......
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