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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 20:14:02 -0700
commit0ea9bb58b2823f74ee99ad9efa63e0be5433354e (patch)
tree21733aba0a9d20e24784c8a48e6ca53876e6dbeb
parentb34e0e1319b31202eb142dcd9688cf7145a30bf6 (diff)
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. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/aio.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 36326dd295da..e609e15f36b9 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;