diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 182b16a91084..c66f238c538d 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -474,6 +474,13 @@ struct bpf_verifier_env { /* longest register parentage chain walked for liveness marking */ u32 longest_mark_read_walk; bpfptr_t fd_array; + + /* bit mask to keep track of whether a register has been accessed + * since the last time the function state was printed + */ + u32 scratched_regs; + /* Same as scratched_regs but for stack slots */ + u64 scratched_stack_slots; }; __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f0604796132f..ded6e816dcd9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -609,6 +609,44 @@ static const char *kernel_type_name(const struct btf* btf, u32 id) return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off); } +static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno) +{ + env->scratched_regs |= 1U << regno; +} + +static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi) +{ + env->scratched_stack_slots |= 1UL << spi; +} + +static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno) +{ + return (env->scratched_regs >> regno) & 1; +} + +static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno) +{ + return (env->scratched_stack_slots >> regno) & 1; +} + +static bool verifier_state_scratched(const struct bpf_verifier_env *env) +{ + return env->scratched_regs || env->scratched_stack_slots; +} + +static void mark_verifier_state_clean(struct bpf_verifier_env *env) +{ + env->scratched_regs = 0U; + env->scratched_stack_slots = 0UL; +} + +/* Used for printing the entire verifier state. */ +static void mark_verifier_state_scratched(struct bpf_verifier_env *env) +{ + env->scratched_regs = ~0U; + env->scratched_stack_slots = ~0UL; +} + /* The reg state of a pointer or a bounded scalar was saved when * it was spilled to the stack. */ @@ -624,7 +662,8 @@ static void scrub_spilled_slot(u8 *stype) } static void print_verifier_state(struct bpf_verifier_env *env, - const struct bpf_func_state *state) + const struct bpf_func_state *state, + bool print_all) { const struct bpf_reg_state *reg; enum bpf_reg_type t; @@ -637,6 +676,8 @@ static void print_verifier_state(struct bpf_verifier_env *env, t = reg->type; if (t == NOT_INIT) continue; + if (!print_all && !reg_scratched(env, i)) + continue; verbose(env, " R%d", i); print_liveness(env, reg->live); verbose(env, "=%s", reg_type_str[t]); @@ -726,6 +767,8 @@ static void print_verifier_state(struct bpf_verifier_env *env, types_buf[BPF_REG_SIZE] = 0; if (!valid) continue; + if (!print_all && !stack_slot_scratched(env, i)) + continue; verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE); print_liveness(env, state->stack[i].spilled_ptr.live); if (is_spilled_reg(&state->stack[i])) { @@ -751,6 +794,7 @@ static void print_verifier_state(struct bpf_verifier_env *env, if (state->in_async_callback_fn) verbose(env, " async_cb"); verbose(env, "\n"); + mark_verifier_state_clean(env); } /* copy array src of length n * size bytes to dst. dst is reallocated if it's too @@ -1541,6 +1585,7 @@ static void init_func_state(struct bpf_verifier_env *env, state->frameno = frameno; state->subprogno = subprogno; init_reg_state(env, state); + mark_verifier_state_scratched(env); } /* Similar to push_stack(), but for async callbacks */ @@ -2228,6 +2273,8 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, return -EINVAL; } + mark_reg_scratched(env, regno); + reg = ®s[regno]; rw64 = is_reg64(env, insn, regno, reg, t); if (t == SRC_OP) { @@ -2678,7 +2725,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno, reg->precise = true; } if (env->log.level & BPF_LOG_LEVEL) { - print_verifier_state(env, func); + print_verifier_state(env, func, false); verbose(env, "parent %s regs=%x stack=%llx marks\n", new_marks ? "didn't have" : "already had", reg_mask, stack_mask); @@ -2837,6 +2884,7 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env, env->insn_aux_data[insn_idx].sanitize_stack_spill = true; } + mark_stack_slot_scratched(env, spi); if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) && !register_is_null(reg) && env->bpf_capable) { if (dst_reg != BPF_REG_FP) { @@ -2958,6 +3006,7 @@ static int check_stack_write_var_off(struct bpf_verifier_env *env, slot = -i - 1; spi = slot / BPF_REG_SIZE; stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; + mark_stack_slot_scratched(env, spi); if (!env->allow_ptr_leaks && *stype != NOT_INIT @@ -3376,7 +3425,7 @@ static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno, * to make sure our theoretical access will be safe. */ if (env->log.level & BPF_LOG_LEVEL) - print_verifier_state(env, state); + print_verifier_state(env, state, false); /* The minimum value is only important with signed * comparisons where we can't assume the floor of a @@ -6011,9 +6060,9 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn if (env->log.level & BPF_LOG_LEVEL) { verbose(env, "caller:\n"); - print_verifier_state(env, caller); + print_verifier_state(env, caller, true); verbose(env, "callee:\n"); - print_verifier_state(env, callee); + print_verifier_state(env, callee, true); } return 0; } @@ -6228,9 +6277,9 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) *insn_idx = callee->callsite + 1; if (env->log.level & BPF_LOG_LEVEL) { verbose(env, "returning from callee:\n"); - print_verifier_state(env, callee); + print_verifier_state(env, callee, true); verbose(env, "to caller at %d:\n", *insn_idx); - print_verifier_state(env, caller); + print_verifier_state(env, caller, true); } /* clear everything in the callee */ free_func_state(callee); @@ -8249,12 +8298,12 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, /* Got here implies adding two SCALAR_VALUEs */ if (WARN_ON_ONCE(ptr_reg)) { - print_verifier_state(env, state); + print_verifier_state(env, state, true); verbose(env, "verifier internal error: unexpected ptr_reg\n"); return -EINVAL; } if (WARN_ON(!src_reg)) { - print_verifier_state(env, state); + print_verifier_state(env, state, true); verbose(env, "verifier internal error: no src_reg\n"); return -EINVAL; } @@ -9389,7 +9438,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, return -EACCES; } if (env->log.level & BPF_LOG_LEVEL) - print_verifier_state(env, this_branch->frame[this_branch->curframe]); + print_verifier_state(env, this_branch->frame[this_branch->curframe], false); return 0; } @@ -11259,14 +11308,17 @@ static int do_check(struct bpf_verifier_env *env) if (env->log.level & BPF_LOG_LEVEL2 || (env->log.level & BPF_LOG_LEVEL && do_print_state)) { - if (env->log.level & BPF_LOG_LEVEL2) - verbose(env, "%d:", env->insn_idx); - else + if (env->log.level & BPF_LOG_LEVEL2) { + if (verifier_state_scratched(env)) + verbose(env, "%d:", env->insn_idx); + } else { verbose(env, "\nfrom %d to %d%s:", env->prev_insn_idx, env->insn_idx, env->cur_state->speculative ? " (speculative execution)" : ""); - print_verifier_state(env, state->frame[state->curframe]); + } + print_verifier_state(env, state->frame[state->curframe], + false); do_print_state = false; } @@ -11488,6 +11540,7 @@ static int do_check(struct bpf_verifier_env *env) if (err) return err; process_bpf_exit: + mark_verifier_state_scratched(env); update_branch_counts(env, env->cur_state); err = pop_stack(env, &prev_insn_idx, &env->insn_idx, pop_log); @@ -14148,6 +14201,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr) } } + mark_verifier_state_clean(env); + if (IS_ERR(btf_vmlinux)) { /* Either gcc or pahole or kernel are broken. */ verbose(env, "in-kernel BTF is malformed\n"); diff --git a/tools/testing/selftests/bpf/prog_tests/align.c b/tools/testing/selftests/bpf/prog_tests/align.c index 837f67c6bfda..aeb2080a67f7 100644 --- a/tools/testing/selftests/bpf/prog_tests/align.c +++ b/tools/testing/selftests/bpf/prog_tests/align.c @@ -39,8 +39,8 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {1, "R1=ctx(id=0,off=0,imm=0)"}, - {1, "R10=fp0"}, + {0, "R1=ctx(id=0,off=0,imm=0)"}, + {0, "R10=fp0"}, {1, "R3_w=inv2"}, {2, "R3_w=inv4"}, {3, "R3_w=inv8"}, @@ -67,8 +67,8 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {1, "R1=ctx(id=0,off=0,imm=0)"}, - {1, "R10=fp0"}, + {0, "R1=ctx(id=0,off=0,imm=0)"}, + {0, "R10=fp0"}, {1, "R3_w=inv1"}, {2, "R3_w=inv2"}, {3, "R3_w=inv4"}, @@ -96,8 +96,8 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {1, "R1=ctx(id=0,off=0,imm=0)"}, - {1, "R10=fp0"}, + {0, "R1=ctx(id=0,off=0,imm=0)"}, + {0, "R10=fp0"}, {1, "R3_w=inv4"}, {2, "R3_w=inv8"}, {3, "R3_w=inv10"}, @@ -118,8 +118,8 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {1, "R1=ctx(id=0,off=0,imm=0)"}, - {1, "R10=fp0"}, + {0, "R1=ctx(id=0,off=0,imm=0)"}, + {0, "R10=fp0"}, {1, "R3_w=inv7"}, {2, "R3_w=inv7"}, {3, "R3_w=inv14"}, @@ -161,13 +161,13 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {7, "R0_w=pkt(id=0,off=8,r=8,imm=0)"}, + {6, "R0_w=pkt(id=0,off=8,r=8,imm=0)"}, {7, "R3_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, {8, "R3_w=inv(id=0,umax_value=510,var_off=(0x0; 0x1fe))"}, {9, "R3_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, {10, "R3_w=inv(id=0,umax_value=2040,var_off=(0x0; 0x7f8))"}, {11, "R3_w=inv(id=0,umax_value=4080,var_off=(0x0; 0xff0))"}, - {18, "R3=pkt_end(id=0,off=0,imm=0)"}, + {13, "R3_w=pkt_end(id=0,off=0,imm=0)"}, {18, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, {19, "R4_w=inv(id=0,umax_value=8160,var_off=(0x0; 0x1fe0))"}, {20, "R4_w=inv(id=0,umax_value=4080,var_off=(0x0; 0xff0))"}, @@ -234,10 +234,10 @@ static struct bpf_align_test tests[] = { }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, .matches = { - {4, "R5_w=pkt(id=0,off=0,r=0,imm=0)"}, + {3, "R5_w=pkt(id=0,off=0,r=0,imm=0)"}, {5, "R5_w=pkt(id=0,off=14,r=0,imm=0)"}, {6, "R4_w=pkt(id=0,off=14,r=0,imm=0)"}, - {10, "R2=pkt(id=0,off=0,r=18,imm=0)"}, + {9, "R2=pkt(id=0,off=0,r=18,imm=0)"}, {10, "R5=pkt(id=0,off=14,r=18,imm=0)"}, {10, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, {14, "R4_w=inv(id=0,umax_value=65535,var_off=(0x0; 0xffff))"}, @@ -296,7 +296,7 @@ static struct bpf_align_test tests[] = { /* Calculated offset in R6 has unknown value, but known * alignment of 4. */ - {8, "R2_w=pkt(id=0,off=0,r=8,imm=0)"}, + {6, "R2_w=pkt(id=0,off=0,r=8,imm=0)"}, {8, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, /* Offset is added to packet pointer R5, resulting in * known fixed offset, and variable offset from R6. @@ -386,7 +386,7 @@ static struct bpf_align_test tests[] = { /* Calculated offset in R6 has unknown value, but known * alignment of 4. */ - {8, "R2_w=pkt(id=0,off=0,r=8,imm=0)"}, + {6, "R2_w=pkt(id=0,off=0,r=8,imm=0)"}, {8, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, /* Adding 14 makes R6 be (4n+2) */ {9, "R6_w=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, @@ -458,7 +458,7 @@ static struct bpf_align_test tests[] = { /* Checked s>=0 */ {9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"}, /* packet pointer + nonnegative (4n+2) */ - {11, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"}, + {12, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"}, {13, "R4_w=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