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

Daniel Borkmann says:

====================
pull-request: bpf 2020-04-15

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

We've added 10 non-merge commits during the last 3 day(s) which contain
a total of 11 files changed, 238 insertions(+), 95 deletions(-).

The main changes are:

1) Fix offset overflow for BPF_MEM BPF_DW insn mapping on arm32 JIT,
   from Luke Nelson and Xi Wang.

2) Prevent mprotect() to make frozen & mmap()'ed BPF map writeable
   again, from Andrii Nakryiko and Jann Horn.

3) Fix type of old_fd in bpf_xdp_set_link_opts to int in libbpf and add
   selftests, from Toke Høiland-Jørgensen.

4) Fix AF_XDP to check that headroom cannot be larger than the available
   space in the chunk, from Magnus Karlsson.

5) Fix reset of XDP prog when expected_fd is set, from David Ahern.

6) Fix a segfault in bpftool's struct_ops command when BTF is not
   available, from Daniel T. Lee.
====================

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

net/core/dev.c

@@ -8667,8 +8667,8 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
 	const struct net_device_ops *ops = dev->netdev_ops;
 	enum bpf_netdev_command query;
 	u32 prog_id, expected_id = 0;
-	struct bpf_prog *prog = NULL;
 	bpf_op_t bpf_op, bpf_chk;
+	struct bpf_prog *prog;
 	bool offload;
 	int err;
 
@@ -8734,6 +8734,7 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
 	} else {
 		if (!prog_id)
 			return 0;
+		prog = NULL;
 	}
 
 	err = dev_xdp_install(dev, bpf_op, extack, flags, prog);

net/xdp/xdp_umem.c

@@ -343,7 +343,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
 	unsigned int chunks, chunks_per_page;
 	u64 addr = mr->addr, size = mr->len;
-	int size_chk, err;
+	int err;
 
 	if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
 		/* Strictly speaking we could support this, if:
@@ -382,8 +382,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 			return -EINVAL;
 	}
 
-	size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM;
-	if (size_chk < 0)
+	if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
 		return -EINVAL;
 
 	umem->address = (unsigned long)addr;