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authorBenjamin LaHaise <bcrl@kvack.org>2014-06-24 13:32:51 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-30 20:09:45 -0700
commitd36db46c2cba973557eb6138d22210c4e0cf17d6 (patch)
tree6f0e481de7b3cfe7321bd129e84013a34446b026 /fs/aio.c
parent6745cb91b5ec93a1b34221279863926fba43d0d7 (diff)
downloadlinux-linaro-stable-d36db46c2cba973557eb6138d22210c4e0cf17d6.tar.gz
aio: fix kernel memory disclosure in io_getevents() introduced in v3.10
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. [jmoyer@redhat.com: backported to 3.10] Signed-off-by: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Petr Matousek <pmatouse@redhat.com> Cc: Kent Overstreet <kmo@daterainc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 8d2c997a550c..ded94c4fa30d 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -717,6 +717,8 @@ static long aio_read_events_ring(struct kioctx *ctx,
if (head == ctx->tail)
goto out;
+ head %= ctx->nr_events;
+
while (ret < nr) {
long avail;
struct io_event *ev;