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Subject[PATCH 3.12 161/181] aio: fix kernel memory disclosure in io_getevents() introduced in v3.10
From: Benjamin LaHaise <>

3.12-stable review patch. If anyone has any objections, please let me know.


commit edfbbf388f293d70bf4b7c0bc38774d05e6f711a upstream.

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 <>
Cc: Mateusz Guzik <>
Cc: Petr Matousek <>
Cc: Kent Overstreet <>
Cc: Jeff Moyer <>
Signed-off-by: Jiri Slaby <>
fs/aio.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/aio.c b/fs/aio.c
index e609e15f36b9..0abde33de70e 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1066,6 +1066,9 @@ static long aio_read_events_ring(struct kioctx *ctx,
head %= ctx->nr_events;
tail %= ctx->nr_events;

+ head %= ctx->nr_events;
+ tail %= ctx->nr_events;
while (ret < nr) {
long avail;
struct io_event *ev;

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