| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 071/150] misc: genwqe: check for error from get_user_pages_fast() | Date | Tue, 13 Jan 2015 23:22:22 -0800 |
| |
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ian Abbott <abbotti@mev.co.uk>
commit cf35d6e0475982667b0d2d318fb27be4b8849827 upstream.
`genwqe_user_vmap()` calls `get_user_pages_fast()` and if the return value is less than the number of pages requested, it frees the pages and returns an error (`-EFAULT`). However, it fails to consider a negative error return value from `get_user_pages_fast()`. In that case, the test `if (rc < m->nr_pages)` will be false (due to promotion of `rc` to a large `unsigned int`) and the code will continue on to call `genwqe_map_pages()` with an invalid list of page pointers. Fix it by bailing out if `get_user_pages_fast()` returns a negative error value.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/misc/genwqe/card_utils.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -590,6 +590,8 @@ int genwqe_user_vmap(struct genwqe_dev * m->nr_pages, 1, /* write by caller */ m->page_list); /* ptrs to pages */ + if (rc < 0) + goto fail_get_user_pages; /* assumption: get_user_pages can be killed by signals. */ if (rc < m->nr_pages) {
|