Patch "RDMA/ucma: Fix use-after-free access in ucma_close" has been added to the 4.4-stable tree

Patch "RDMA/ucma: Fix use-after-free access in ucma_close" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    RDMA/ucma: Fix use-after-free access in ucma_close

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rdma-ucma-fix-use-after-free-access-in-ucma_close.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ed65a4dc22083e73bac599ded6a262318cad7baf Mon Sep 17 00:00:00 2001
From: Leon Romanovsky <leonro@mellanox.com>
Date: Mon, 19 Mar 2018 14:20:15 +0200
Subject: RDMA/ucma: Fix use-after-free access in ucma_close

From: Leon Romanovsky <leonro@mellanox.com>

commit ed65a4dc22083e73bac599ded6a262318cad7baf upstream.

The error in ucma_create_id() left ctx in the list of contexts belong
to ucma file descriptor. The attempt to close this file descriptor causes
to use-after-free accesses while iterating over such list.

Fixes: 75216638572f ("RDMA/cma: Export rdma cm interface to userspace")
Reported-by: <syzbot+dcfd344365a56fbebd0f@syzkaller.appspotmail.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/core/ucma.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -494,6 +494,9 @@ err1:
 	mutex_lock(&mut);
 	idr_remove(&ctx_idr, ctx->id);
 	mutex_unlock(&mut);
+	mutex_lock(&file->mut);
+	list_del(&ctx->list);
+	mutex_unlock(&file->mut);
 	kfree(ctx);
 	return ret;
 }


Patches currently in stable-queue which might be from leonro@mellanox.com are

queue-4.4/rdma-ucma-check-af-family-prior-resolving-address.patch
queue-4.4/rdma-ucma-don-t-allow-join-attempts-for-unsupported-af-family.patch
queue-4.4/rdma-ucma-check-that-device-is-connected-prior-to-access-it.patch
queue-4.4/rdma-ucma-fix-use-after-free-access-in-ucma_close.patch
queue-4.4/rdma-ucma-ensure-that-cm_id-exists-prior-to-access-it.patch
queue-4.4/rdma-ucma-check-that-device-exists-prior-to-accessing-it.patch