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authorMagnus Karlsson <magnus.karlsson@intel.com>2019-10-21 10:16:58 +0200
committerAlexei Starovoitov <ast@kernel.org>2019-10-23 20:22:11 -0700
commit2afd23f78f39da84937006ecd24aa664a4ab052b (patch)
tree3c042b80af88bd4aa97fd25a7069935153817be4
parent3b4d9eb2ee74dd5ea7fa36cffb0ca7f5bc4924da (diff)
xsk: Fix registration of Rx-only sockets
Having Rx-only AF_XDP sockets can potentially lead to a crash in the system by a NULL pointer dereference in xsk_umem_consume_tx(). This function iterates through a list of all sockets tied to a umem and checks if there are any packets to send on the Tx ring. Rx-only sockets do not have a Tx ring, so this will cause a NULL pointer dereference. This will happen if you have registered one or more Rx-only sockets to a umem and the driver is checking the Tx ring even on Rx, or if the XDP_SHARED_UMEM mode is used and there is a mix of Rx-only and other sockets tied to the same umem. Fixed by only putting sockets with a Tx component on the list that xsk_umem_consume_tx() iterates over. Fixes: ac98d8aab61b ("xsk: wire upp Tx zero-copy functions") Reported-by: Kal Cutter Conley <kal.conley@dectris.com> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Link: https://lore.kernel.org/bpf/1571645818-16244-1-git-send-email-magnus.karlsson@intel.com
-rw-r--r--net/xdp/xdp_umem.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 16d5f353163a..3049af269fbf 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -27,6 +27,9 @@ void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
{
unsigned long flags;
+ if (!xs->tx)
+ return;
+
spin_lock_irqsave(&umem->xsk_list_lock, flags);
list_add_rcu(&xs->list, &umem->xsk_list);
spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
@@ -36,6 +39,9 @@ void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
{
unsigned long flags;
+ if (!xs->tx)
+ return;
+
spin_lock_irqsave(&umem->xsk_list_lock, flags);
list_del_rcu(&xs->list);
spin_unlock_irqrestore(&umem->xsk_list_lock, flags);