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bianbu-linux-6.6/tools/testing/selftests/bpf/verifier/precise.c
Andrii Nakryiko c50c0b57a5 bpf: fix mark_all_scalars_precise use in mark_chain_precision 
When precision backtracking bails out due to some unsupported sequence
of instructions (e.g., stack access through register other than r10), we
need to mark all SCALAR registers as precise to be safe. Currently,
though, we mark SCALARs precise only starting from the state we detected
unsupported condition, which could be one of the parent states of the
actual current state. This will leave some registers potentially not
marked as precise, even though they should. So make sure we start
marking scalars as precise from current state (env->cur_state).

Further, we don't currently detect a situation when we end up with some
stack slots marked as needing precision, but we ran out of available
states to find the instructions that populate those stack slots. This is
akin the `i >= func->allocated_stack / BPF_REG_SIZE` check and should be
handled similarly by falling back to marking all SCALARs precise. Add
this check when we run out of states.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-05-04 22:35:35 -07:00

258 lines
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{
"precise: test 1",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_LD_MAP_FD(BPF_REG_6, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=scalar(umin=1, umax=8) */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.fixup_map_array_48b = { 1 },
.result = VERBOSE_ACCEPT,
.errstr =
"mark_precise: frame0: last_idx 26 first_idx 20\
mark_precise: frame0: regs=r2 stack= before 25\
mark_precise: frame0: regs=r2 stack= before 24\
mark_precise: frame0: regs=r2 stack= before 23\
mark_precise: frame0: regs=r2 stack= before 22\
mark_precise: frame0: regs=r2 stack= before 20\
mark_precise: frame0: parent state regs=r2 stack=:\
mark_precise: frame0: last_idx 19 first_idx 10\
mark_precise: frame0: regs=r2 stack= before 19\
mark_precise: frame0: regs=r9 stack= before 18\
mark_precise: frame0: regs=r8,r9 stack= before 17\
mark_precise: frame0: regs=r0,r9 stack= before 15\
mark_precise: frame0: regs=r0,r9 stack= before 14\
mark_precise: frame0: regs=r9 stack= before 13\
mark_precise: frame0: regs=r9 stack= before 12\
mark_precise: frame0: regs=r9 stack= before 11\
mark_precise: frame0: regs=r9 stack= before 10\
mark_precise: frame0: parent state regs= stack=:",
},
{
"precise: test 2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_LD_MAP_FD(BPF_REG_6, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=scalar(umin=1, umax=8) */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.fixup_map_array_48b = { 1 },
.result = VERBOSE_ACCEPT,
.flags = BPF_F_TEST_STATE_FREQ,
.errstr =
"26: (85) call bpf_probe_read_kernel#113\
mark_precise: frame0: last_idx 26 first_idx 22\
mark_precise: frame0: regs=r2 stack= before 25\
mark_precise: frame0: regs=r2 stack= before 24\
mark_precise: frame0: regs=r2 stack= before 23\
mark_precise: frame0: regs=r2 stack= before 22\
mark_precise: frame0: parent state regs=r2 stack=:\
mark_precise: frame0: last_idx 20 first_idx 20\
mark_precise: frame0: regs=r2 stack= before 20\
mark_precise: frame0: parent state regs=r2 stack=:\
mark_precise: frame0: last_idx 19 first_idx 17\
mark_precise: frame0: regs=r2 stack= before 19\
mark_precise: frame0: regs=r9 stack= before 18\
mark_precise: frame0: regs=r8,r9 stack= before 17\
mark_precise: frame0: parent state regs= stack=:",
},
{
"precise: cross frame pruning",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV64_IMM(BPF_REG_8, 1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV64_IMM(BPF_REG_9, 1),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.flags = BPF_F_TEST_STATE_FREQ,
.errstr = "!read_ok",
.result = REJECT,
},
{
"precise: ST insn causing spi > allocated_stack",
.insns = {
BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
BPF_JMP_IMM(BPF_JNE, BPF_REG_3, 123, 0),
BPF_ST_MEM(BPF_DW, BPF_REG_3, -8, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_MOV64_IMM(BPF_REG_0, -1),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.flags = BPF_F_TEST_STATE_FREQ,
.errstr = "mark_precise: frame0: last_idx 5 first_idx 5\
mark_precise: frame0: parent state regs=r4 stack=:\
mark_precise: frame0: last_idx 4 first_idx 2\
mark_precise: frame0: regs=r4 stack= before 4\
mark_precise: frame0: regs=r4 stack= before 3\
mark_precise: frame0: regs= stack=-8 before 2\
mark_precise: frame0: falling back to forcing all scalars precise\
force_precise: frame0: forcing r0 to be precise\
mark_precise: frame0: last_idx 5 first_idx 5\
mark_precise: frame0: parent state regs= stack=:",
.result = VERBOSE_ACCEPT,
.retval = -1,
},
{
"precise: STX insn causing spi > allocated_stack",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
BPF_JMP_IMM(BPF_JNE, BPF_REG_3, 123, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, -8),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_MOV64_IMM(BPF_REG_0, -1),
BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.flags = BPF_F_TEST_STATE_FREQ,
.errstr = "mark_precise: frame0: last_idx 6 first_idx 6\
mark_precise: frame0: parent state regs=r4 stack=:\
mark_precise: frame0: last_idx 5 first_idx 3\
mark_precise: frame0: regs=r4 stack= before 5\
mark_precise: frame0: regs=r4 stack= before 4\
mark_precise: frame0: regs= stack=-8 before 3\
mark_precise: frame0: falling back to forcing all scalars precise\
force_precise: frame0: forcing r0 to be precise\
force_precise: frame0: forcing r0 to be precise\
force_precise: frame0: forcing r0 to be precise\
force_precise: frame0: forcing r0 to be precise\
mark_precise: frame0: last_idx 6 first_idx 6\
mark_precise: frame0: parent state regs= stack=:",
.result = VERBOSE_ACCEPT,
.retval = -1,
},
{
"precise: mark_chain_precision for ARG_CONST_ALLOC_SIZE_OR_ZERO",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, offsetof(struct xdp_md, ingress_ifindex)),
BPF_LD_MAP_FD(BPF_REG_6, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_IMM(BPF_REG_2, 1),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_4, 0, 1),
BPF_MOV64_IMM(BPF_REG_2, 0x1000),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 42),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_submit),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map_ringbuf = { 1 },
.prog_type = BPF_PROG_TYPE_XDP,
.flags = BPF_F_TEST_STATE_FREQ,
.errstr = "invalid access to memory, mem_size=1 off=42 size=8",
.result = REJECT,
},
{
"precise: program doesn't prematurely prune branches",
.insns = {
BPF_ALU64_IMM(BPF_MOV, BPF_REG_6, 0x400),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_7, 0),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_8, 0),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_9, 0x80000000),
BPF_ALU64_IMM(BPF_MOD, BPF_REG_6, 0x401),
BPF_JMP_IMM(BPF_JA, 0, 0, 0),
BPF_JMP_REG(BPF_JLE, BPF_REG_6, BPF_REG_9, 2),
BPF_ALU64_IMM(BPF_MOD, BPF_REG_6, 1),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_9, 0),
BPF_JMP_REG(BPF_JLE, BPF_REG_6, BPF_REG_9, 1),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_6, 0),
BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 0),
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4),
BPF_LD_MAP_FD(BPF_REG_4, 0),
BPF_ALU64_REG(BPF_MOV, BPF_REG_1, BPF_REG_4),
BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_RSH, BPF_REG_6, 10),
BPF_ALU64_IMM(BPF_MUL, BPF_REG_6, 8192),
BPF_ALU64_REG(BPF_MOV, BPF_REG_1, BPF_REG_0),
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_6),
BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_3, 0),
BPF_EXIT_INSN(),
},
.fixup_map_array_48b = { 13 },
.prog_type = BPF_PROG_TYPE_XDP,
.result = REJECT,
.errstr = "register with unbounded min value is not allowed",
},
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