xref: /llvm-project/clang/test/Sema/format-strings.c (revision d806cbc98df7baec96991170de5f5f9134a248e9)
1 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral %s
2 
3 #include <stdarg.h>
4 typedef __typeof(sizeof(int)) size_t;
5 typedef struct _FILE FILE;
6 int fprintf(FILE *, const char *restrict, ...);
7 int printf(const char *restrict, ...);
8 int snprintf(char *restrict, size_t, const char *restrict, ...);
9 int sprintf(char *restrict, const char *restrict, ...);
10 int vasprintf(char **, const char *, va_list);
11 int vfprintf(FILE *, const char *restrict, va_list);
12 int vprintf(const char *restrict, va_list);
13 int vsnprintf(char *, size_t, const char *, va_list);
14 int vsprintf(char *restrict, const char *restrict, va_list);
15 
16 char * global_fmt;
17 
18 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
19 
20   char * b;
21   va_list ap;
22   va_start(ap,buf);
23 
24   printf(s); // expected-warning {{format string is not a string literal}}
25   vprintf(s,ap); // // no-warning
26   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
27   vfprintf(fp,s,ap); // no-warning
28   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
29   vasprintf(&b,s,ap); // no-warning
30   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
31   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
32   __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
33   __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
34   vsprintf(buf,s,ap); // no-warning
35   vsnprintf(buf,2,s,ap); // no-warning
36   vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
37   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
38   __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
39 
40   // rdar://6079877
41   printf("abc"
42          "%*d", (unsigned) 1, 1); // expected-warning {{field width should have type 'int'}}
43   printf("abc\
44 def"
45          "%*d", (unsigned) 1, 1); // expected-warning {{field width should have type 'int'}}
46 
47 }
48 
49 void check_conditional_literal(const char* s, int i) {
50   printf(i == 1 ? "yes" : "no"); // no-warning
51   printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
52   printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
53   printf("yes" ?: "no %d", 1); // expected-warning{{more data arguments than '%' conversions}}
54 }
55 
56 void check_writeback_specifier()
57 {
58   int x;
59   char *b;
60 
61   printf("%n",&x); // expected-warning {{'%n' in format string discouraged}}
62   sprintf(b,"%d%%%n",1, &x); // expected-warning {{'%n' in format string dis}}
63 }
64 
65 void check_invalid_specifier(FILE* fp, char *buf)
66 {
67   printf("%s%lb%d","unix",10,20); // expected-warning {{lid conversion '%lb'}}
68   fprintf(fp,"%%%l"); // expected-warning {{lid conversion '%l'}}
69   sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // no-warning
70   snprintf(buf, 2, "%%%%%ld%;%d", 1, 2, 3); // expected-warning {{sion '%;'}}
71 }
72 
73 void check_null_char_string(char* b)
74 {
75   printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
76   snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
77   printf("%\0d",1); // expected-warning {{string contains '\0'}}
78 }
79 
80 void check_empty_format_string(char* buf, ...)
81 {
82   va_list ap;
83   va_start(ap,buf);
84   vprintf("",ap); // expected-warning {{format string is empty}}
85   sprintf(buf,""); // expected-warning {{format string is empty}}
86 }
87 
88 void check_wide_string(char* b, ...)
89 {
90   va_list ap;
91   va_start(ap,b);
92 
93   printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
94   vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
95 }
96 
97 void check_asterisk_precision_width(int x) {
98   printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
99   printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
100   printf("%*d",12,x); // no-warning
101   printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
102   printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
103 }
104 
105 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
106 
107 void test_myprintf() {
108   myprintf("%d", 17, 18); // okay
109 }
110 
111 void test_constant_bindings(void) {
112   const char * const s1 = "hello";
113   const char s2[] = "hello";
114   const char *s3 = "hello";
115   char * const s4 = "hello";
116   extern const char s5[];
117 
118   printf(s1); // no-warning
119   printf(s2); // no-warning
120   printf(s3); // expected-warning{{not a string literal}}
121   printf(s4); // expected-warning{{not a string literal}}
122   printf(s5); // expected-warning{{not a string literal}}
123 }
124 
125 
126 // Test what happens when -Wformat-security only.
127 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
128 #pragma GCC diagnostic warning "-Wformat-security"
129 
130 void test9(char *P) {
131   int x;
132   printf(P);   // expected-warning {{format string is not a string literal (potentially insecure)}}
133   printf(P, 42);
134   printf("%n", &x); // expected-warning {{use of '%n' in format string discouraged }}
135 }
136 
137 void torture(va_list v8) {
138   vprintf ("%*.*d", v8);  // no-warning
139 }
140 
141