diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/test_align.c | 66 |
1 files changed, 64 insertions, 2 deletions
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c index 74cc4a6b8ed0..b0816830a937 100644 --- a/tools/testing/selftests/bpf/test_align.c +++ b/tools/testing/selftests/bpf/test_align.c @@ -441,6 +441,62 @@ static struct bpf_align_test tests[] = { {23, "R5=pkt(id=2,off=0,r=4,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, }, }, + { + .descr = "dubious pointer arithmetic", + .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), + 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) + */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + /* Then make sure it's nonnegative */ + BPF_JMP_IMM(BPF_JSGE, BPF_REG_5, 0, 1), + BPF_EXIT_INSN(), + /* Add it to packet pointer */ + BPF_MOV64_REG(BPF_REG_6, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_5), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_6), + 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_4, BPF_REG_6, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = REJECT, + .matches = { + {4, "R5=pkt(id=0,off=0,r=0,imm=0)"}, + /* ptr & 0x40 == either 0 or 0x40 */ + {5, "R5=inv(id=0,umax_value=64,var_off=(0x0; 0x40))"}, + /* ptr << 2 == unknown, (4n) */ + {7, "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))"}, + /* Checked s>=0 */ + {10, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + /* packet pointer + nonnegative (4n+2) */ + {12, "R6=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))"}, + /* 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. + */ + {16, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + } + }, }; static int probe_filter_length(const struct bpf_insn *fp) @@ -470,10 +526,15 @@ static int do_test_single(struct bpf_align_test *test) fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER, prog, prog_len, 1, "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 2); - if (fd_prog < 0) { + if (fd_prog < 0 && test->result != REJECT) { printf("Failed to load program.\n"); printf("%s", bpf_vlog); ret = 1; + } else if (fd_prog >= 0 && test->result == REJECT) { + printf("Unexpected success to load!\n"); + printf("%s", bpf_vlog); + ret = 1; + close(fd_prog); } else { ret = 0; /* We make a local copy so that we can strtok() it */ @@ -506,7 +567,8 @@ static int do_test_single(struct bpf_align_test *test) break; } } - close(fd_prog); + if (fd_prog >= 0) + close(fd_prog); } return ret; } |