selftests/bpf: Offloaded prog after non-offloaded should not cause BUG

Check what happens if non-offloaded dev bound BPF
program is followed by offloaded dev bound program.
Test case adapated from syzbot report [1].

[1] https://lore.kernel.org/bpf/000000000000d97f3c060479c4f8@google.com/

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230912005539.2248244-3-eddyz87@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Eduard Zingerman 2023-09-12 03:55:38 +03:00 committed by Martin KaFai Lau
parent 1a49f4195d
commit e4c3116473
1 changed files with 61 additions and 0 deletions

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// SPDX-License-Identifier: GPL-2.0
#include <net/if.h>
#include <test_progs.h>
#include <network_helpers.h>
#define LOCAL_NETNS "xdp_dev_bound_only_netns"
static int load_dummy_prog(char *name, __u32 ifindex, __u32 flags)
{
struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN() };
LIBBPF_OPTS(bpf_prog_load_opts, opts);
opts.prog_flags = flags;
opts.prog_ifindex = ifindex;
return bpf_prog_load(BPF_PROG_TYPE_XDP, name, "GPL", insns, ARRAY_SIZE(insns), &opts);
}
/* A test case for bpf_offload_netdev->offload handling bug:
* - create a veth device (does not support offload);
* - create a device bound XDP program with BPF_F_XDP_DEV_BOUND_ONLY flag
* (such programs are not offloaded);
* - create a device bound XDP program without flags (such programs are offloaded).
* This might lead to 'BUG: kernel NULL pointer dereference'.
*/
void test_xdp_dev_bound_only_offdev(void)
{
struct nstoken *tok = NULL;
__u32 ifindex;
int fd1 = -1;
int fd2 = -1;
SYS(out, "ip netns add " LOCAL_NETNS);
tok = open_netns(LOCAL_NETNS);
if (!ASSERT_OK_PTR(tok, "open_netns"))
goto out;
SYS(out, "ip link add eth42 type veth");
ifindex = if_nametoindex("eth42");
if (!ASSERT_NEQ(ifindex, 0, "if_nametoindex")) {
perror("if_nametoindex");
goto out;
}
fd1 = load_dummy_prog("dummy1", ifindex, BPF_F_XDP_DEV_BOUND_ONLY);
if (!ASSERT_GE(fd1, 0, "load_dummy_prog #1")) {
perror("load_dummy_prog #1");
goto out;
}
/* Program with ifindex is considered offloaded, however veth
* does not support offload => error should be reported.
*/
fd2 = load_dummy_prog("dummy2", ifindex, 0);
ASSERT_EQ(fd2, -EINVAL, "load_dummy_prog #2 (offloaded)");
out:
close(fd1);
close(fd2);
close_netns(tok);
/* eth42 was added inside netns, removing the netns will
* also remove eth42 veth pair.
*/
SYS_NOFAIL("ip netns del " LOCAL_NETNS);
}