| { |
| "raw_tracepoint_writable: reject variable offset", |
| .insns = { |
| /* r6 is our tp buffer */ |
| BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), |
| |
| BPF_LD_MAP_FD(BPF_REG_1, 0), |
| /* move the key (== 0) to r10-8 */ |
| BPF_MOV32_IMM(BPF_REG_0, 0), |
| BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), |
| BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), |
| BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0), |
| /* lookup in the map */ |
| BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, |
| BPF_FUNC_map_lookup_elem), |
| |
| /* exit clean if null */ |
| BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), |
| BPF_EXIT_INSN(), |
| |
| /* shift the buffer pointer to a variable location */ |
| BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0), |
| BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0), |
| /* clobber whatever's there */ |
| BPF_MOV64_IMM(BPF_REG_7, 4242), |
| BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0), |
| |
| BPF_MOV64_IMM(BPF_REG_0, 0), |
| BPF_EXIT_INSN(), |
| }, |
| .fixup_map_hash_8b = { 1, }, |
| .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, |
| .errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)", |
| .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, |
| }, |
