| Message ID | 20230912005539.2248244-3-eddyz87@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e4c31164737e9a00de1be6455e2c667ac5478b3c |
| Delegated to: | BPF |
| Headers | show |
| Series | Avoid dummy bpf_offload_netdev in __bpf_prog_dev_bound_init | expand |
On 9/11/23 5:55 PM, Eduard Zingerman wrote: > 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> > --- > .../bpf/prog_tests/xdp_dev_bound_only.c | 58 +++++++++++++++++++ > 1 file changed, 58 insertions(+) > create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c b/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c > new file mode 100644 > index 000000000000..5ee4c16d2e21 > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c > @@ -0,0 +1,58 @@ > +// 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" > + > +int load_dummy_prog(char *name, __u32 ifindex, __u32 flags) I added static. > +{ > + 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); Also added NULL check for tok. > + 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); > + SYS_NOFAIL("ip link delete eth42"); > + SYS_NOFAIL("ip netns del " LOCAL_NETNS); > + if (tok) close_netns() can handle NULL, so removed this tok check. Applied. Thanks for the fix and test! > + close_netns(tok); > +}
On Mon, 2023-09-11 at 23:26 -0700, Martin KaFai Lau wrote: > On 9/11/23 5:55 PM, Eduard Zingerman wrote: [...] > > +int load_dummy_prog(char *name, __u32 ifindex, __u32 flags) > > I added static. [...] > > + tok = open_netns(LOCAL_NETNS); > > Also added NULL check for tok. [...] > > + if (tok) > > close_netns() can handle NULL, so removed this tok check. > > Applied. Thanks for the fix and test! Sorry, I should have noticed these issues before sending. Thank you for fixing it up.
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c b/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c new file mode 100644 index 000000000000..5ee4c16d2e21 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c @@ -0,0 +1,58 @@ +// 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" + +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); + 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); + SYS_NOFAIL("ip link delete eth42"); + SYS_NOFAIL("ip netns del " LOCAL_NETNS); + if (tok) + close_netns(tok); +}
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> --- .../bpf/prog_tests/xdp_dev_bound_only.c | 58 +++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_dev_bound_only.c