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| author |   Ian Abbott <abbotti@mev.co.uk> | 2014-11-06 16:23:39 +0000 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-07 10:26:46 -0800 |
| commit | cf35d6e0475982667b0d2d318fb27be4b8849827 (patch) | |
| tree | 45f0b776d4f9497e793cbfa1f0afe59e85606004 /drivers/misc | |
| parent | char: misc: document behaviour of open() (diff) | |
| download | linux-dev-cf35d6e0475982667b0d2d318fb27be4b8849827.tar.xz linux-dev-cf35d6e0475982667b0d2d318fb27be4b8849827.zip | |
misc: genwqe: check for error from get_user_pages_fast()
`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>
Cc: <stable@vger.kernel.org> # 3.14.x # 3.15.x # 3.16.x # 3.17.x
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/genwqe/card_utils.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 7cb3b7e41739..1ca94e6fa8fb 100644 --- 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 *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) { |