Patch "RDMA/uverbs: Check port number supplied by user verbs cmds" has been added to the 4.12-stable tree

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

RDMA/uverbs: Check port number supplied by user verbs cmds

to the 4.12-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-uverbs-check-port-number-supplied-by-user-verbs-cmds.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Boris Pismenny <[email protected]>
Date: Tue, 27 Jun 2017 15:09:13 +0300
Subject: RDMA/uverbs: Check port number supplied by user verbs cmds

From: Boris Pismenny <[email protected]>

commit 5ecce4c9b17bed4dc9cb58bfb10447307569b77b upstream.

The ib_uverbs_create_ah() ind ib_uverbs_modify_qp() calls receive the port number from user input as part of its attributes and assumes it is valid. Down on the stack, that parameter is used to access kernel data structures. If the value is invalid, the kernel accesses memory it should not. To prevent this, verify the port number before using it.

BUG: KASAN: use-after-free in ib_uverbs_create_ah+0x6d5/0x7b0
Read of size 4 at addr ffff880018d67ab8 by task syz-executor/313

BUG: KASAN: slab-out-of-bounds in modify_qp.isra.4+0x19d0/0x1ef0
Read of size 4 at addr ffff88006c40ec58 by task syz-executor/819

---
 drivers/infiniband/core/uverbs_cmd.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -1931,6 +1931,11 @@ static int modify_qp(struct ib_uverbs_fi
 		goto out;
 	}
 
+	if (!rdma_is_port_valid(qp->device, cmd->base.port_num)) {
+		ret = -EINVAL;
+		goto release_qp;
+	}
+
 	attr->qp_state		  = cmd->base.qp_state;
 	attr->cur_qp_state	  = cmd->base.cur_qp_state;
 	attr->path_mtu		  = cmd->base.path_mtu;

@@ -2541,6 +2546,9 @@ ssize_t ib_uverbs_create_ah(struct ib_uv
 	if (copy_from_user(&cmd, buf, sizeof cmd))
 		return -EFAULT;
 
+	if (!rdma_is_port_valid(ib_dev, cmd.attr.port_num))
+		return -EINVAL;
+
 	INIT_UDATA(&udata, buf + sizeof(cmd),
 		   (unsigned long)cmd.response + sizeof(resp),
 		   in_len - sizeof(cmd), out_len - sizeof(resp));

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/rdma-uverbs-check-port-number-supplied-by-user-verbs-cmds.patch