From: Alexei Starovoitov <ast@kernel.org>
Date: Tue, 23 Jan 2018 20:05:51 -0800
Subject: selftests/bpf: make 'dubious pointer arithmetic' test useful
Patch-mainline: v4.16-rc1
Git-commit: 31e95b61e172144bb2b626a291db1bdc0769275b
References: bsc#1083647
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>
Acked-by: Gary Lin <glin@suse.com>
---
tools/testing/selftests/bpf/test_align.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
--- 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)
@@ -473,20 +471,18 @@ 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)"},
- /* ptr & 0x40 == either 0 or 0x40 */
- {5, "R5_w=inv(id=0,umax_value=64,var_off=(0x0; 0x40))"},
- /* ptr << 2 == unknown, (4n) */
- {7, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc))"},
+ {4, "R5=pkt_end(id=0,off=0,imm=0)"},
+ /* (ptr - ptr) << 2 == unknown, (4n) */
+ {6, "R5=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.
*/
- {8, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"},
+ {7, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"},
/* Checked s>=0 */
- {10, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+ {9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
/* packet pointer + nonnegative (4n+2) */
- {12, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
- {14, "R4=pkt(id=1,off=4,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+ {11, "R6=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
@@ -494,7 +490,7 @@ static struct bpf_align_test tests[] = {
* So we did not get a 'range' on R6, and the access
* attempt will fail.
*/
- {16, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+ {15, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
}
},
{