From 53ea2076d851ee37e4f3954c5ae569439b138248 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 2 Sep 2020 10:52:23 +0200 Subject: [PATCH] xsk: Fix possible segfault in xsk umem diagnostics Fix possible segfault in the xsk diagnostics code when dumping information about the umem. This can happen when a umem has been created, but the socket has not been bound yet. In this case, the xsk buffer pool does not exist yet and we cannot dump the information that was moved from the umem to the buffer pool. Fix this by testing for the existence of the buffer pool and if not there, do not dump any of that information. Fixes: c2d3d6a47462 ("xsk: Move queue_id, dev and need_wakeup to buffer pool") Fixes: 7361f9c3d719 ("xsk: Move fill and completion rings to buffer pool") Reported-by: syzbot+3f04d36b7336f7868066@syzkaller.appspotmail.com Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/1599036743-26454-1-git-send-email-magnus.karlsson@intel.com --- net/xdp/xsk_diag.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/net/xdp/xsk_diag.c b/net/xdp/xsk_diag.c index 5bd8ea9d206a..c014217f5fa7 100644 --- a/net/xdp/xsk_diag.c +++ b/net/xdp/xsk_diag.c @@ -59,22 +59,20 @@ static int xsk_diag_put_umem(const struct xdp_sock *xs, struct sk_buff *nlskb) du.num_pages = umem->npgs; du.chunk_size = umem->chunk_size; du.headroom = umem->headroom; - du.ifindex = pool->netdev ? pool->netdev->ifindex : 0; - du.queue_id = pool->queue_id; + du.ifindex = (pool && pool->netdev) ? pool->netdev->ifindex : 0; + du.queue_id = pool ? pool->queue_id : 0; du.flags = 0; if (umem->zc) du.flags |= XDP_DU_F_ZEROCOPY; du.refs = refcount_read(&umem->users); err = nla_put(nlskb, XDP_DIAG_UMEM, sizeof(du), &du); - - if (!err && pool->fq) + if (!err && pool && pool->fq) err = xsk_diag_put_ring(pool->fq, XDP_DIAG_UMEM_FILL_RING, nlskb); - if (!err && pool->cq) { - err = xsk_diag_put_ring(pool->cq, XDP_DIAG_UMEM_COMPLETION_RING, - nlskb); - } + if (!err && pool && pool->cq) + err = xsk_diag_put_ring(pool->cq, + XDP_DIAG_UMEM_COMPLETION_RING, nlskb); return err; }