diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2018-01-23 20:05:51 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-01-24 10:39:58 +0100 |
| commit | 31e95b61e172144bb2b626a291db1bdc0769275b (patch) | |
| tree | f64c8ada251c8120e8c8e40daa5b90d77be43228 /tools | |
| parent | 783687810e986a15ffbf86c516a1a48ff37f38f7 (diff) | |
| download | linux-31e95b61e172144bb2b626a291db1bdc0769275b.tar.bz2 | |
selftests/bpf: make 'dubious pointer arithmetic' test useful
mostly revert the previous workaround and make
'dubious pointer arithmetic' test useful again.
Use (ptr - ptr) << const instead of ptr << const to generate large scalar.
The rest stays as before commit 2b36047e7889.
Fixes: 2b36047e7889 ("selftests/bpf: fix test_align")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/test_align.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c index e19b410125eb..ff8bd7e3e50c 100644 --- a/tools/testing/selftests/bpf/test_align.c +++ b/tools/testing/selftests/bpf/test_align.c @@ -446,11 +446,9 @@ static struct bpf_align_test tests[] = { .insns = { PREP_PKT_POINTERS, BPF_MOV64_IMM(BPF_REG_0, 0), - /* ptr & const => unknown & const */ - BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), - BPF_ALU64_IMM(BPF_AND, BPF_REG_5, 0x40), - /* ptr << const => unknown << const */ - BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + /* (ptr - ptr) << 2 */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_3), + BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_2), BPF_ALU64_IMM(BPF_LSH, BPF_REG_5, 2), /* We have a (4n) value. Let's make a packet offset * out of it. First add 14, to make it a (4n+2) @@ -473,8 +471,26 @@ static struct bpf_align_test tests[] = { .prog_type = BPF_PROG_TYPE_SCHED_CLS, .result = REJECT, .matches = { - {4, "R5_w=pkt(id=0,off=0,r=0,imm=0)"}, - /* R5 bitwise operator &= on pointer prohibited */ + {4, "R5_w=pkt_end(id=0,off=0,imm=0)"}, + /* (ptr - ptr) << 2 == unknown, (4n) */ + {6, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc))"}, + /* (4n) + 14 == (4n+2). We blow our bounds, because + * the add could overflow. + */ + {7, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"}, + /* Checked s>=0 */ + {9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + /* packet pointer + nonnegative (4n+2) */ + {11, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + {13, "R4=pkt(id=1,off=4,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + /* NET_IP_ALIGN + (4n+2) == (4n), alignment is fine. + * We checked the bounds, but it might have been able + * to overflow if the packet pointer started in the + * upper half of the address space. + * So we did not get a 'range' on R6, and the access + * attempt will fail. + */ + {15, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, } }, { |