| /* | |
| * Buggy verifier accepted the program below while not patching BPF_PSEUDO_FUNC | |
| * load instruction to contain a real address. Which resulted in a function call | |
| * to a bogus address. | |
| */ | |
| { | |
| "BPF_PSEUDO_FUNC reference to the main program", | |
| .insns = { | |
| /* r6 = bpf_map_lookup_elem(&timer_map, &(int){0}); */ | |
| BPF_ST_MEM(BPF_W, BPF_REG_10, -4, 0), | |
| BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), | |
| BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), | |
| BPF_LD_MAP_FD(BPF_REG_1, 0), | |
| BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), | |
| BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10), | |
| BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), | |
| /* bpf_timer_init(r6, &timer_map, 0); */ | |
| BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), | |
| BPF_LD_MAP_FD(BPF_REG_2, 0), | |
| BPF_MOV64_IMM(BPF_REG_3, 0), | |
| BPF_EMIT_CALL(BPF_FUNC_timer_init), | |
| /* bpf_timer_set_callback(r6, <insn #0>); */ | |
| BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), | |
| BPF_RAW_INSN(BPF_LD | BPF_IMM | BPF_DW, BPF_REG_2, BPF_PSEUDO_FUNC, 0, -15), | |
| BPF_RAW_INSN(0, 0, 0, 0, 0), | |
| BPF_EMIT_CALL(BPF_FUNC_timer_set_callback), | |
| BPF_MOV64_IMM(BPF_REG_0, 0), | |
| BPF_EXIT_INSN(), | |
| }, | |
| .prog_type = BPF_PROG_TYPE_TRACEPOINT, | |
| .fixup_map_timer = { 3, 9 }, | |
| .result = REJECT, | |
| .errstr = "callback function cannot be the main program", | |
| .func_info = { { 0, 4 /* main_prog */ } }, | |
| .func_info_cnt = 1, | |
| .btf_strings = "\0int\0ctx\0main_prog", | |
| .btf_types = { | |
| /* 1: int */ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), | |
| /* 2: void* */ BTF_PTR_ENC(0), | |
| /* 3: int __(void *) */ BTF_FUNC_PROTO_ENC(1, 1), | |
| BTF_FUNC_PROTO_ARG_ENC(5, 2), | |
| /* 4: main_prog */ BTF_FUNC_ENC(9, 3), | |
| BTF_END_RAW | |
| } | |
| }, |