Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Andrii Nakryiko says:

====================
pull-request: bpf 2021-07-15

The following pull-request contains BPF updates for your *net* tree.

We've added 9 non-merge commits during the last 5 day(s) which contain
a total of 9 files changed, 37 insertions(+), 15 deletions(-).

The main changes are:

1) Fix NULL pointer dereference in BPF_TEST_RUN for BPF_XDP_DEVMAP and
   BPF_XDP_CPUMAP programs, from Xuan Zhuo.

2) Fix use-after-free of net_device in XDP bpf_link, from Xuan Zhuo.

3) Follow-up fix to subprog poke descriptor use-after-free problem, from
   Daniel Borkmann and John Fastabend.

4) Fix out-of-range array access in s390 BPF JIT backend, from Colin Ian King.

5) Fix memory leak in BPF sockmap, from John Fastabend.

6) Fix for sockmap to prevent proc stats reporting bug, from John Fastabend
   and Jakub Sitnicki.

7) Fix NULL pointer dereference in bpftool, from Tobias Klauser.

8) AF_XDP documentation fixes, from Baruch Siach.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 4 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 7aeefc467ddc..8f1a47ad6781 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9712,14 +9712,17 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	struct net_device *dev;
 	int err, fd;
 
+	rtnl_lock();
 	dev = dev_get_by_index(net, attr->link_create.target_ifindex);
-	if (!dev)
+	if (!dev) {
+		rtnl_unlock();
 		return -EINVAL;
+	}
 
 	link = kzalloc(sizeof(*link), GFP_USER);
 	if (!link) {
 		err = -ENOMEM;
-		goto out_put_dev;
+		goto unlock;
 	}
 
 	bpf_link_init(&link->link, BPF_LINK_TYPE_XDP, &bpf_xdp_link_lops, prog);
@@ -9729,14 +9732,14 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err) {
 		kfree(link);
-		goto out_put_dev;
+		goto unlock;
 	}
 
-	rtnl_lock();
 	err = dev_xdp_attach_link(dev, NULL, link);
 	rtnl_unlock();
 
 	if (err) {
+		link->dev = NULL;
 		bpf_link_cleanup(&link_primer);
 		goto out_put_dev;
 	}
@@ -9746,6 +9749,9 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 	dev_put(dev);
 	return fd;
 
+unlock:
+	rtnl_unlock();
+
 out_put_dev:
 	dev_put(dev);
 	return err;