xref: /llvm-project/clang/test/Sema/format-strings.c (revision c3bdff7c8c9c0faa49cf0fc7683ff977ca3a1df9)
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 asprintf(char **, const char *, ...);
12 int vfprintf(FILE *, const char *restrict, va_list);
13 int vprintf(const char *restrict, va_list);
14 int vsnprintf(char *, size_t, const char *, va_list);
15 int vsprintf(char *restrict, const char *restrict, va_list);
16 
17 char * global_fmt;
18 
19 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
20 
21   char * b;
22   va_list ap;
23   va_start(ap,buf);
24 
25   printf(s); // expected-warning {{format string is not a string literal}}
26   vprintf(s,ap); // // no-warning
27   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
28   vfprintf(fp,s,ap); // no-warning
29   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
30   vasprintf(&b,s,ap); // no-warning
31   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
32   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
33   __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
34   __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
35   vsprintf(buf,s,ap); // no-warning
36   vsnprintf(buf,2,s,ap); // no-warning
37   vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
38   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
39   __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
40 
41   // rdar://6079877
42   printf("abc"
43          "%*d", 1, 1); // no-warning
44   printf("abc\
45 def"
46          "%*d", 1, 1); // no-warning
47 
48   // <rdar://problem/6079850>, allow 'unsigned' (instead of 'int') to be used for both
49   // the field width and precision.  This deviates from C99, but is reasonably safe
50   // and is also accepted by GCC.
51   printf("%*d", (unsigned) 1, 1); // no-warning
52 }
53 
54 void check_conditional_literal(const char* s, int i) {
55   printf(i == 1 ? "yes" : "no"); // no-warning
56   printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
57   printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
58   printf("yes" ?: "no %d", 1); // expected-warning{{more data arguments than format specifiers}}
59 }
60 
61 void check_writeback_specifier()
62 {
63   int x;
64   char *b;
65 
66   printf("%n",&x); // expected-warning {{'%n' in format string discouraged}}
67   sprintf(b,"%d%%%n",1, &x); // expected-warning {{'%n' in format string dis}}
68 }
69 
70 void check_invalid_specifier(FILE* fp, char *buf)
71 {
72   printf("%s%lb%d","unix",10,20); // expected-warning {{invalid conversion specifier 'b'}}
73   fprintf(fp,"%%%l"); // expected-warning {{incomplete format specifier}}
74   sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // expected-warning{{conversion specifies type 'long' but the argument has type 'int'}}
75   snprintf(buf, 2, "%%%%%ld%;%d", 1, 2, 3); // expected-warning{{conversion specifies type 'long' but the argument has type 'int'}} expected-warning {{invalid conversion specifier ';'}}
76 }
77 
78 void check_null_char_string(char* b)
79 {
80   printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
81   snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
82   printf("%\0d",1); // expected-warning {{string contains '\0'}}
83 }
84 
85 void check_empty_format_string(char* buf, ...)
86 {
87   va_list ap;
88   va_start(ap,buf);
89   vprintf("",ap); // expected-warning {{format string is empty}}
90   sprintf(buf,""); // expected-warning {{format string is empty}}
91 }
92 
93 void check_wide_string(char* b, ...)
94 {
95   va_list ap;
96   va_start(ap,b);
97 
98   printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
99   vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
100 }
101 
102 void check_asterisk_precision_width(int x) {
103   printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
104   printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
105   printf("%*d",12,x); // no-warning
106   printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
107   printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
108 }
109 
110 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
111 
112 void test_myprintf() {
113   myprintf("%d", 17, 18); // okay
114 }
115 
116 void test_constant_bindings(void) {
117   const char * const s1 = "hello";
118   const char s2[] = "hello";
119   const char *s3 = "hello";
120   char * const s4 = "hello";
121   extern const char s5[];
122 
123   printf(s1); // no-warning
124   printf(s2); // no-warning
125   printf(s3); // expected-warning{{not a string literal}}
126   printf(s4); // expected-warning{{not a string literal}}
127   printf(s5); // expected-warning{{not a string literal}}
128 }
129 
130 
131 // Test what happens when -Wformat-security only.
132 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
133 #pragma GCC diagnostic warning "-Wformat-security"
134 
135 void test9(char *P) {
136   int x;
137   printf(P);   // expected-warning {{format string is not a string literal (potentially insecure)}}
138   printf(P, 42);
139   printf("%n", &x); // expected-warning {{use of '%n' in format string discouraged }}
140 }
141 
142 void torture(va_list v8) {
143   vprintf ("%*.*d", v8);  // no-warning
144 
145 }
146 
147 void test10(int x, float f, int i) {
148   printf("%@", 12); // expected-warning{{invalid conversion specifier '@'}}
149   printf("\0"); // expected-warning{{format string contains '\0' within the string body}}
150   printf("xs\0"); // expected-warning{{format string contains '\0' within the string body}}
151   printf("%*d\n"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
152   printf("%*.*d\n", x); // expected-warning{{'.*' specified field precision is missing a matching 'int' argument}}
153   printf("%*d\n", f, x); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
154   printf("%*.*d\n", x, f, x); // expected-warning{{field precision should have type 'int', but argument has type 'double'}}
155   printf("%**\n"); // expected-warning{{invalid conversion specifier '*'}}
156   printf("%n", &i); // expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
157   printf("%d%d\n", x); // expected-warning{{more '%' conversions than data arguments}}
158   printf("%d\n", x, x); // expected-warning{{more data arguments than format specifiers}}
159   printf("%W%d%Z\n", x, x, x); // expected-warning{{invalid conversion specifier 'W'}} expected-warning{{invalid conversion specifier 'Z'}}
160   printf("%"); // expected-warning{{incomplete format specifier}}
161   printf("%.d", x); // no-warning
162   printf("%.", x);  // expected-warning{{incomplete format specifier}}
163 }
164 
165 typedef struct __aslclient *aslclient;
166 typedef struct __aslmsg *aslmsg;
167 int asl_log(aslclient asl, aslmsg msg, int level, const char *format, ...) __attribute__((__format__ (__printf__, 4, 5)));
168 void test_asl(aslclient asl) {
169   // Test case from <rdar://problem/7341605>.
170   asl_log(asl, 0, 3, "Error: %m"); // no-warning
171   asl_log(asl, 0, 3, "Error: %W"); // expected-warning{{invalid conversion specifier 'W'}}
172 }
173