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authorIan Abbott <abbotti@mev.co.uk>2014-11-06 16:23:39 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-16 06:59:31 -0800
commit7de4a0e7fe4390dfc3b42c1fdcd53104758cc33c (patch)
parente9820ed9a247ea5b018d71bf0af750acf0c02451 (diff)
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 <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 0 deletions
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,
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) {