From: Ian Abbott Date: Thu, 6 Nov 2014 16:23:39 +0000 (+0000) Subject: misc: genwqe: check for error from get_user_pages_fast() X-Git-Tag: v3.14.29~41 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7de4a0e7fe4390dfc3b42c1fdcd53104758cc33c;p=platform%2Fkernel%2Flinux-stable.git misc: genwqe: check for error from get_user_pages_fast() 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 6b1a6ef9f1a8..0c3a64708409 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -490,6 +490,8 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr, 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) {