A kernel memory disclosure was introduced in aio_read_events_ring() in v3.10 by commit a31ad380bed817aa25f8830ad23e1a0480fef797. The changes made to aio_read_events_ring() failed to correctly limit the index into ctx->ring_pages[], allowing an attacked to cause the subsequent kmap() of an arbitrary page with a copy_to_user() to copy the contents into userspace. This vulnerability has been assigned CVE-2014-0206. Thanks to Mateusz and Petr for disclosing this issue.
This patch applies to v3.12+. A separate backport is needed for 3.10/3.11. Signed-off-by: Benjamin LaHaise <b...@kvack.org> Cc: Mateusz Guzik <mgu...@redhat.com> Cc: Petr Matousek <pmato...@redhat.com> Cc: Kent Overstreet <k...@daterainc.com> Cc: Jeff Moyer <jmo...@redhat.com> Cc: sta...@vger.kernel.org --- fs/aio.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/aio.c b/fs/aio.c index 6a9c7e4..955947e 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1063,6 +1063,9 @@ static long aio_read_events_ring(struct kioctx *ctx, if (head == tail) goto out; + head %= ctx->nr_events; + tail %= ctx->nr_events; + while (ret < nr) { long avail; struct io_event *ev; -- 1.8.2.1 -- "Thought is the essence of where you are now." -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/