From f78331f74cacb33d87cd60376dacc5bd397959e2 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Tue, 3 Nov 2020 10:41:29 +0100 Subject: [PATCH] libbpf: Fix null dereference in xsk_socket__delete Fix a possible null pointer dereference in xsk_socket__delete that will occur if a null pointer is fed into the function. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Reported-by: Andrii Nakryiko Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1604396490-12129-2-git-send-email-magnus.karlsson@gmail.com --- tools/lib/bpf/xsk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index e3c98c007825..504b7a85d445 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -891,13 +891,14 @@ int xsk_umem__delete(struct xsk_umem *umem) void xsk_socket__delete(struct xsk_socket *xsk) { size_t desc_sz = sizeof(struct xdp_desc); - struct xsk_ctx *ctx = xsk->ctx; struct xdp_mmap_offsets off; + struct xsk_ctx *ctx; int err; if (!xsk) return; + ctx = xsk->ctx; if (ctx->prog_fd != -1) { xsk_delete_bpf_maps(xsk); close(ctx->prog_fd);