6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiayuan Chen [ Upstream commit ad27ed7d2309419a129078d781504f486b1b469a ] bpf_xdp_link_update() calls dev_xdp_install() directly and skips dev_xdp_attach(), so the checks in dev_xdp_attach() do not run. A user can make an XDP link with a normal program and then swap in an offloaded or device-bound program with BPF_LINK_UPDATE, which puts it on the software path. dev_xdp_install() is the one place all three paths go through: "ip link set xdp" and BPF_LINK_CREATE reach it via dev_xdp_attach(), and BPF_LINK_UPDATE calls it directly. So move the program checks (offloaded, bound to another device, device-bound in generic mode, native vs generic, DEVMAP and CPUMAP) there, and keep only the netlink-flag check (XDP_FLAGS_UPDATE_IF_NOEXIST) in dev_xdp_attach(). Fixes: 026a4c28e1db3 ("bpf, xdp: Implement LINK_UPDATE for BPF XDP link") Signed-off-by: Jiayuan Chen Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/dev.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 9888affc68df3..8f507292f8ba4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9627,6 +9627,37 @@ static int dev_xdp_install(struct net_device *dev, enum bpf_xdp_mode mode, return -EBUSY; } + if (prog) { + enum bpf_xdp_mode other_mode = mode == XDP_MODE_SKB + ? XDP_MODE_DRV : XDP_MODE_SKB; + bool offload = mode == XDP_MODE_HW; + + if (!offload && dev_xdp_prog(dev, other_mode)) { + NL_SET_ERR_MSG(extack, "Native and generic XDP can't be active at the same time"); + return -EEXIST; + } + if (!offload && bpf_prog_is_offloaded(prog->aux)) { + NL_SET_ERR_MSG(extack, "Using offloaded program without HW_MODE flag is not supported"); + return -EINVAL; + } + if (bpf_prog_is_dev_bound(prog->aux) && !bpf_offload_dev_match(prog, dev)) { + NL_SET_ERR_MSG(extack, "Program bound to different device"); + return -EINVAL; + } + if (bpf_prog_is_dev_bound(prog->aux) && mode == XDP_MODE_SKB) { + NL_SET_ERR_MSG(extack, "Can't attach device-bound programs in generic mode"); + return -EINVAL; + } + if (prog->expected_attach_type == BPF_XDP_DEVMAP) { + NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device"); + return -EINVAL; + } + if (prog->expected_attach_type == BPF_XDP_CPUMAP) { + NL_SET_ERR_MSG(extack, "BPF_XDP_CPUMAP programs can not be attached to a device"); + return -EINVAL; + } + } + memset(&xdp, 0, sizeof(xdp)); xdp.command = mode == XDP_MODE_HW ? XDP_SETUP_PROG_HW : XDP_SETUP_PROG; xdp.extack = extack; -- 2.53.0