diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 21 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 46 |
2 files changed, 62 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b7014606745b..59ed07b9b4ea 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -481,6 +481,13 @@ static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) regs[regno].max_value = BPF_REGISTER_MAX_RANGE; } +static void mark_reg_unknown_value_and_range(struct bpf_reg_state *regs, + u32 regno) +{ + mark_reg_unknown_value(regs, regno); + reset_reg_range_values(regs, regno); +} + enum reg_arg_type { SRC_OP, /* register is used as source operand */ DST_OP, /* register is used as destination operand */ @@ -532,6 +539,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type) switch (type) { case PTR_TO_MAP_VALUE: case PTR_TO_MAP_VALUE_OR_NULL: + case PTR_TO_MAP_VALUE_ADJ: case PTR_TO_STACK: case PTR_TO_CTX: case PTR_TO_PACKET: @@ -616,7 +624,8 @@ static int check_stack_read(struct bpf_verifier_state *state, int off, int size, } if (value_regno >= 0) /* have read misc data from the stack */ - mark_reg_unknown_value(state->regs, value_regno); + mark_reg_unknown_value_and_range(state->regs, + value_regno); return 0; } } @@ -825,7 +834,8 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, else err = check_map_access(env, regno, off, size); if (!err && t == BPF_READ && value_regno >= 0) - mark_reg_unknown_value(state->regs, value_regno); + mark_reg_unknown_value_and_range(state->regs, + value_regno); } else if (reg->type == PTR_TO_CTX) { enum bpf_reg_type reg_type = UNKNOWN_VALUE; @@ -837,7 +847,8 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, } err = check_ctx_access(env, off, size, t, ®_type); if (!err && t == BPF_READ && value_regno >= 0) { - mark_reg_unknown_value(state->regs, value_regno); + mark_reg_unknown_value_and_range(state->regs, + value_regno); /* note that reg.[id|off|range] == 0 */ state->regs[value_regno].type = reg_type; } @@ -870,7 +881,8 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, } err = check_packet_access(env, regno, off, size); if (!err && t == BPF_READ && value_regno >= 0) - mark_reg_unknown_value(state->regs, value_regno); + mark_reg_unknown_value_and_range(state->regs, + value_regno); } else { verbose("R%d invalid mem access '%s'\n", regno, reg_type_str[reg->type]); @@ -2744,7 +2756,6 @@ static int do_check(struct bpf_verifier_env *env) if (err) return err; - reset_reg_range_values(regs, insn->dst_reg); if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) { insn_idx++; diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index b7732e557bf9..e7b075819c08 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -3396,6 +3396,52 @@ static struct bpf_test tests[] = { .result = REJECT, .prog_type = BPF_PROG_TYPE_TRACEPOINT, }, + { + "map element value is preserved across register spilling", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + 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, 6), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 42), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -184), + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_3, 0, 42), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 leaks addr", + .result = ACCEPT, + .result_unpriv = REJECT, + }, + { + "map element value (adjusted) is preserved across register spilling", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + 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, 7), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, + offsetof(struct test_val, foo)), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 42), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -184), + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_3, 0, 42), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .result = ACCEPT, + .result_unpriv = REJECT, + }, }; static int probe_filter_length(const struct bpf_insn *fp) |