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| author | Daniel Borkmann <daniel@iogearbox.net> | 2018-01-31 14:58:56 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-02-01 18:43:56 +0300 |
| commit | 65073a67331de3d2cce35607807ddec284e75e81 (patch) | |
| tree | aa39697a25f7b47548ca227b13d866558c9b98ce /tools | |
| parent | 62a06994ced17f295fc51ea0815580ee7ccb668d (diff) | |
| download | linux-65073a67331de3d2cce35607807ddec284e75e81.tar.xz | |
bpf: fix null pointer deref in bpf_prog_test_run_xdp
syzkaller was able to generate the following XDP program ...
(18) r0 = 0x0
(61) r5 = *(u32 *)(r1 +12)
(04) (u32) r0 += (u32) 0
(95) exit
... and trigger a NULL pointer dereference in ___bpf_prog_run()
via bpf_prog_test_run_xdp() where this was attempted to run.
Reason is that recent xdp_rxq_info addition to XDP programs
updated all drivers, but not bpf_prog_test_run_xdp(), where
xdp_buff is set up. Thus when context rewriter does the deref
on the netdev it's NULL at runtime. Fix it by using xdp_rxq
from loopback dev. __netif_get_rx_queue() helper can also be
reused in various other locations later on.
Fixes: 02dd3291b2f0 ("bpf: finally expose xdp_rxq_info to XDP bpf-programs")
Reported-by: syzbot+1eb094057b338eb1fc00@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 697bd83de295..c0f16e93f9bd 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -7780,6 +7780,20 @@ static struct bpf_test tests[] = { .result = REJECT, }, { + "XDP, using ifindex from netdev", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct xdp_md, ingress_ifindex)), + BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 1, 1), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_XDP, + .retval = 1, + }, + { "meta access, test1", .insns = { BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, |