Commit edfbbf38 authored Jun 24, 2014 by Benjamin LaHaise

aio: fix kernel memory disclosure in io_getevents() introduced in v3.10



A kernel memory disclosure was introduced in aio_read_events_ring() in v3.10
by commit a31ad380.  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 <bcrl@kvack.org>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: stable@vger.kernel.org

parent f8567a38

fs/aio.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;

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