type_val: ignore fake member assignments from uncasted calls
[smatch.git] / check_buffer_too_small_for_struct.c
blobe741fbd58bd61a05601aa9efff400472e2b4fe9f
1 /*
2 * Copyright (C) 2014 Oracle.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
18 #include "smatch.h"
20 static int my_id;
22 STATE(too_small);
24 static void match_assign(struct expression *expr)
26 struct symbol *left_type, *right_type;
27 struct expression *size_expr;
28 sval_t min_size;
30 left_type = get_type(expr->left);
31 if (!left_type || left_type->type != SYM_PTR)
32 return;
33 left_type = get_real_base_type(left_type);
34 if (!left_type || left_type->type != SYM_STRUCT)
35 return;
37 right_type = get_type(expr->right);
38 if (!right_type || right_type->type != SYM_PTR)
39 return;
40 right_type = get_real_base_type(right_type);
41 if (!right_type)
42 return;
43 if (right_type != &void_ctype && type_bits(right_type) != 8)
44 return;
46 size_expr = get_size_variable(expr->right);
47 if (!size_expr)
48 return;
50 get_absolute_min(size_expr, &min_size);
51 if (min_size.value >= type_bytes(left_type))
52 return;
54 set_state_expr(my_id, expr->left, &too_small);
57 static void match_dereferences(struct expression *expr)
59 struct symbol *left_type;
60 struct expression *right;
61 struct smatch_state *state;
62 char *name;
63 struct expression *size_expr;
64 sval_t min_size;
66 if (expr->type != EXPR_PREOP)
67 return;
69 expr = strip_expr(expr->unop);
70 state = get_state_expr(my_id, expr);
71 if (state != &too_small)
72 return;
74 left_type = get_type(expr);
75 if (!left_type || left_type->type != SYM_PTR)
76 return;
77 left_type = get_real_base_type(left_type);
78 if (!left_type || left_type->type != SYM_STRUCT)
79 return;
81 right = get_assigned_expr(expr);
82 size_expr = get_size_variable(right);
83 if (!size_expr)
84 return;
86 get_absolute_min(size_expr, &min_size);
87 if (min_size.value >= type_bytes(left_type))
88 return;
90 name = expr_to_str(right);
91 sm_msg("warn: is '%s' large enough for 'struct %s'? %s", name, left_type->ident ? left_type->ident->name : "<anon>", sval_to_str(min_size));
92 free_string(name);
93 set_state_expr(my_id, expr, &undefined);
96 void check_buffer_too_small_for_struct(int id)
98 my_id = id;
100 add_hook(&match_assign, ASSIGNMENT_HOOK);
101 add_hook(&match_dereferences, DEREF_HOOK);