diff options
| -rw-r--r-- | tools/testing/selftests/bpf/test_align.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c index 62232e4d0332..74cc4a6b8ed0 100644 --- a/tools/testing/selftests/bpf/test_align.c +++ b/tools/testing/selftests/bpf/test_align.c @@ -374,6 +374,73 @@ static struct bpf_align_test tests[] = { {33, "R5=pkt(id=4,off=18,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"}, }, }, + { + .descr = "packet variable offset 2", + .insns = { + /* Create an unknown offset, (4n+2)-aligned */ + LOAD_UNKNOWN(BPF_REG_6), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14), + /* Add it to the packet pointer */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + /* Make a (4n) offset from the value we just read */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xff), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + /* Add it to the packet pointer */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + /* Calculated offset in R6 has unknown value, but known + * alignment of 4. + */ + {8, "R2=pkt(id=0,off=0,r=8,imm=0)"}, + {8, "R6=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Adding 14 makes R6 be (4n+2) */ + {9, "R6=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* Packet pointer has (4n+2) offset */ + {11, "R5=pkt(id=1,off=0,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + {13, "R4=pkt(id=1,off=4,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {15, "R5=pkt(id=1,off=0,r=4,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* Newly read value in R6 was shifted left by 2, so has + * known alignment of 4. + */ + {18, "R6=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Added (4n) to packet pointer's (4n+2) var_off, giving + * another (4n+2). + */ + {19, "R5=pkt(id=2,off=0,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + {21, "R4=pkt(id=2,off=4,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {23, "R5=pkt(id=2,off=0,r=4,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + }, + }, }; static int probe_filter_length(const struct bpf_insn *fp) |