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1 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs %s
2 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs -fno-signed-char %s
3 
4 #include <stdarg.h>
5 #include <stddef.h>
6 #define __need_wint_t
7 #include <stddef.h> // For wint_t and wchar_t
8 
9 typedef struct _FILE FILE;
10 int fprintf(FILE *, const char *restrict, ...);
11 int printf(const char *restrict, ...); // expected-note{{passing argument to parameter here}}
12 int snprintf(char *restrict, size_t, const char *restrict, ...);
13 int sprintf(char *restrict, const char *restrict, ...);
14 int vasprintf(char **, const char *, va_list);
15 int asprintf(char **, const char *, ...);
16 int vfprintf(FILE *, const char *restrict, va_list);
17 int vprintf(const char *restrict, va_list);
18 int vsnprintf(char *, size_t, const char *, va_list);
19 int vsprintf(char *restrict, const char *restrict, va_list); // expected-note{{passing argument to parameter here}}
20 
21 int vscanf(const char *restrict format, va_list arg);
22 
23 char * global_fmt;
24 
check_string_literal(FILE * fp,const char * s,char * buf,...)25 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
26 
27   char * b;
28   va_list ap;
29   va_start(ap,buf);
30 
31   printf(s); // expected-warning {{format string is not a string literal}}
32   // expected-note@-1{{treat the string as an argument to avoid this}}
33   vprintf(s,ap); // expected-warning {{format string is not a string literal}}
34   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
35   // expected-note@-1{{treat the string as an argument to avoid this}}
36   vfprintf(fp,s,ap); // expected-warning {{format string is not a string literal}}
37   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
38   // expected-note@-1{{treat the string as an argument to avoid this}}
39   vasprintf(&b,s,ap); // expected-warning {{format string is not a string literal}}
40   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
41   // expected-note@-1{{treat the string as an argument to avoid this}}
42   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
43   // expected-note@-1{{treat the string as an argument to avoid this}}
44   __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
45   // expected-note@-1{{treat the string as an argument to avoid this}}
46   __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
47   // expected-note@-1{{treat the string as an argument to avoid this}}
48   vsprintf(buf,s,ap); // expected-warning {{format string is not a string lit}}
49   vsnprintf(buf,2,s,ap); // expected-warning {{format string is not a string lit}}
50   vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
51   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // expected-warning {{format string is not a string lit}}
52   __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
53 
54   vscanf(s, ap); // expected-warning {{format string is not a string literal}}
55 
56   const char *const fmt = "%d"; // FIXME -- defined here
57   printf(fmt, 1, 2); // expected-warning{{data argument not used}}
58 
59   // rdar://6079877
60   printf("abc"
61          "%*d", 1, 1); // no-warning
62   printf("abc\
63 def"
64          "%*d", 1, 1); // no-warning
65 
66   // <rdar://problem/6079850>, allow 'unsigned' (instead of 'int') to be used for both
67   // the field width and precision.  This deviates from C99, but is reasonably safe
68   // and is also accepted by GCC.
69   printf("%*d", (unsigned) 1, 1); // no-warning
70 }
71 
72 // When calling a non-variadic format function (vprintf, vscanf, NSLogv, ...),
73 // warn only if the format string argument is a parameter that is not itself
74 // declared as a format string with compatible format.
75 __attribute__((__format__ (__printf__, 2, 4)))
check_string_literal2(FILE * fp,const char * s,char * buf,...)76 void check_string_literal2( FILE* fp, const char* s, char *buf, ... ) {
77   char * b;
78   va_list ap;
79   va_start(ap,buf);
80 
81   printf(s); // expected-warning {{format string is not a string literal}}
82   // expected-note@-1{{treat the string as an argument to avoid this}}
83   vprintf(s,ap); // no-warning
84   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
85   // expected-note@-1{{treat the string as an argument to avoid this}}
86   vfprintf(fp,s,ap); // no-warning
87   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
88   // expected-note@-1{{treat the string as an argument to avoid this}}
89   vasprintf(&b,s,ap); // no-warning
90   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
91   // expected-note@-1{{treat the string as an argument to avoid this}}
92   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
93   // expected-note@-1{{treat the string as an argument to avoid this}}
94   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
95 
96   vscanf(s, ap); // expected-warning {{format string is not a string literal}}
97 }
98 
check_conditional_literal(const char * s,int i)99 void check_conditional_literal(const char* s, int i) {
100   printf(i == 1 ? "yes" : "no"); // no-warning
101   printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
102   printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
103   // expected-note@-1{{treat the string as an argument to avoid this}}
104   printf("yes" ?: "no %d", 1); // expected-warning{{data argument not used by format string}}
105   printf(0 ? "yes %s" : "no %d", 1); // no-warning
106   printf(0 ? "yes %d" : "no %s", 1); // expected-warning{{format specifies type 'char *'}}
107 
108   printf(0 ? "yes" : "no %d", 1); // no-warning
109   printf(0 ? "yes %d" : "no", 1); // expected-warning{{data argument not used by format string}}
110   printf(1 ? "yes" : "no %d", 1); // expected-warning{{data argument not used by format string}}
111   printf(1 ? "yes %d" : "no", 1); // no-warning
112   printf(i ? "yes" : "no %d", 1); // no-warning
113   printf(i ? "yes %s" : "no %d", 1); // expected-warning{{format specifies type 'char *'}}
114   printf(i ? "yes" : "no %d", 1, 2); // expected-warning{{data argument not used by format string}}
115 
116   printf(i ? "%*s" : "-", i, s); // no-warning
117   printf(i ? "yes" : 0 ? "no %*d" : "dont know %d", 1, 2); // expected-warning{{data argument not used by format string}}
118   printf(i ? "%i\n" : "%i %s %s\n", i, s); // expected-warning{{more '%' conversions than data arguments}}
119 }
120 
check_writeback_specifier()121 void check_writeback_specifier()
122 {
123   int x;
124   char *b;
125   printf("%n", b); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
126   printf("%n", &x); // no-warning
127 
128   printf("%hhn", (signed char*)0); // no-warning
129   printf("%hhn", (char*)0); // no-warning
130   printf("%hhn", (unsigned char*)0); // no-warning
131   printf("%hhn", (int*)0); // expected-warning{{format specifies type 'signed char *' but the argument has type 'int *'}}
132 
133   printf("%hn", (short*)0); // no-warning
134   printf("%hn", (unsigned short*)0); // no-warning
135   printf("%hn", (int*)0); // expected-warning{{format specifies type 'short *' but the argument has type 'int *'}}
136 
137   printf("%n", (int*)0); // no-warning
138   printf("%n", (unsigned int*)0); // no-warning
139   printf("%n", (char*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
140 
141   printf("%ln", (long*)0); // no-warning
142   printf("%ln", (unsigned long*)0); // no-warning
143   printf("%ln", (int*)0); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
144 
145   printf("%lln", (long long*)0); // no-warning
146   printf("%lln", (unsigned long long*)0); // no-warning
147   printf("%lln", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
148 
149   printf("%qn", (long long*)0); // no-warning
150   printf("%qn", (unsigned long long*)0); // no-warning
151   printf("%qn", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
152 
153   printf("%Ln", 0); // expected-warning{{length modifier 'L' results in undefined behavior or no effect with 'n' conversion specifier}}
154   // expected-note@-1{{did you mean to use 'll'?}}
155 }
156 
check_invalid_specifier(FILE * fp,char * buf)157 void check_invalid_specifier(FILE* fp, char *buf)
158 {
159   printf("%s%lb%d","unix",10,20); // expected-warning {{invalid conversion specifier 'b'}}
160   fprintf(fp,"%%%l"); // expected-warning {{incomplete format specifier}}
161   sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
162   snprintf(buf, 2, "%%%%%ld%;%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}} expected-warning {{invalid conversion specifier ';'}}
163 }
164 
check_null_char_string(char * b)165 void check_null_char_string(char* b)
166 {
167   printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
168   snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
169   printf("%\0d",1); // expected-warning {{string contains '\0'}}
170 }
171 
check_empty_format_string(char * buf,...)172 void check_empty_format_string(char* buf, ...)
173 {
174   va_list ap;
175   va_start(ap,buf);
176   vprintf("",ap); // expected-warning {{format string is empty}}
177   sprintf(buf, "", 1); // expected-warning {{format string is empty}}
178 
179   // Don't warn about empty format strings when there are no data arguments.
180   // This can arise from macro expansions and non-standard format string
181   // functions.
182   sprintf(buf, ""); // no-warning
183 }
184 
check_wide_string(char * b,...)185 void check_wide_string(char* b, ...)
186 {
187   va_list ap;
188   va_start(ap,b);
189 
190   printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
191   vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
192 }
193 
check_asterisk_precision_width(int x)194 void check_asterisk_precision_width(int x) {
195   printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
196   printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
197   printf("%*d",12,x); // no-warning
198   printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
199   printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
200 }
201 
202 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
203 
test_myprintf()204 void test_myprintf() {
205   myprintf("%d", 17, 18); // okay
206 }
207 
test_constant_bindings(void)208 void test_constant_bindings(void) {
209   const char * const s1 = "hello";
210   const char s2[] = "hello";
211   const char *s3 = "hello";
212   char * const s4 = "hello";
213   extern const char s5[];
214 
215   printf(s1); // no-warning
216   printf(s2); // no-warning
217   printf(s3); // expected-warning{{not a string literal}}
218   // expected-note@-1{{treat the string as an argument to avoid this}}
219   printf(s4); // expected-warning{{not a string literal}}
220   // expected-note@-1{{treat the string as an argument to avoid this}}
221   printf(s5); // expected-warning{{not a string literal}}
222   // expected-note@-1{{treat the string as an argument to avoid this}}
223 }
224 
225 
226 // Test what happens when -Wformat-security only.
227 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
228 #pragma GCC diagnostic warning "-Wformat-security"
229 
test9(char * P)230 void test9(char *P) {
231   int x;
232   printf(P);   // expected-warning {{format string is not a string literal (potentially insecure)}}
233   // expected-note@-1{{treat the string as an argument to avoid this}}
234   printf(P, 42);
235 }
236 
torture(va_list v8)237 void torture(va_list v8) {
238   vprintf ("%*.*d", v8);  // no-warning
239 
240 }
241 
test10(int x,float f,int i,long long lli)242 void test10(int x, float f, int i, long long lli) {
243   printf("%s"); // expected-warning{{more '%' conversions than data arguments}}
244   printf("%@", 12); // expected-warning{{invalid conversion specifier '@'}}
245   printf("\0"); // expected-warning{{format string contains '\0' within the string body}}
246   printf("xs\0"); // expected-warning{{format string contains '\0' within the string body}}
247   printf("%*d\n"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
248   printf("%*.*d\n", x); // expected-warning{{'.*' specified field precision is missing a matching 'int' argument}}
249   printf("%*d\n", f, x); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
250   printf("%*.*d\n", x, f, x); // expected-warning{{field precision should have type 'int', but argument has type 'double'}}
251   printf("%**\n"); // expected-warning{{invalid conversion specifier '*'}}
252   printf("%d%d\n", x); // expected-warning{{more '%' conversions than data arguments}}
253   printf("%d\n", x, x); // expected-warning{{data argument not used by format string}}
254   printf("%W%d\n", x, x); // expected-warning{{invalid conversion specifier 'W'}}
255   printf("%"); // expected-warning{{incomplete format specifier}}
256   printf("%.d", x); // no-warning
257   printf("%.", x);  // expected-warning{{incomplete format specifier}}
258   printf("%f", 4); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
259   printf("%qd", lli); // no-warning
260   printf("%qd", x); // expected-warning{{format specifies type 'long long' but the argument has type 'int'}}
261   printf("%qp", (void *)0); // expected-warning{{length modifier 'q' results in undefined behavior or no effect with 'p' conversion specifier}}
262   printf("hhX %hhX", (unsigned char)10); // no-warning
263   printf("llX %llX", (long long) 10); // no-warning
264   // This is fine, because there is an implicit conversion to an int.
265   printf("%d", (unsigned char) 10); // no-warning
266   printf("%d", (long long) 10); // expected-warning{{format specifies type 'int' but the argument has type 'long long'}}
267   printf("%Lf\n", (long double) 1.0); // no-warning
268   printf("%f\n", (long double) 1.0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
269   // The man page says that a zero precision is okay.
270   printf("%.0Lf", (long double) 1.0); // no-warning
271   printf("%c\n", "x"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
272   printf("%c\n", 1.23); // expected-warning{{format specifies type 'int' but the argument has type 'double'}}
273   printf("Format %d, is %! %f", 1, 2, 4.4); // expected-warning{{invalid conversion specifier '!'}}
274 }
275 
276 typedef unsigned char uint8_t;
277 
should_understand_small_integers()278 void should_understand_small_integers() {
279   printf("%hhu", (short) 10); // expected-warning{{format specifies type 'unsigned char' but the argument has type 'short'}}
280   printf("%hu\n", (unsigned char) 1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'unsigned char'}}
281   printf("%hu\n", (uint8_t)1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'uint8_t'}}
282 }
283 
test11(void * p,char * s)284 void test11(void *p, char *s) {
285   printf("%p", p); // no-warning
286   printf("%p", 123); // expected-warning{{format specifies type 'void *' but the argument has type 'int'}}
287   printf("%.4p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
288   printf("%+p", p); // expected-warning{{flag '+' results in undefined behavior with 'p' conversion specifier}}
289   printf("% p", p); // expected-warning{{flag ' ' results in undefined behavior with 'p' conversion specifier}}
290   printf("%0p", p); // expected-warning{{flag '0' results in undefined behavior with 'p' conversion specifier}}
291   printf("%s", s); // no-warning
292   printf("%+s", p); // expected-warning{{flag '+' results in undefined behavior with 's' conversion specifier}}
293   printf("% s", p); // expected-warning{{flag ' ' results in undefined behavior with 's' conversion specifier}}
294   printf("%0s", p); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
295 }
296 
test12(char * b)297 void test12(char *b) {
298   unsigned char buf[4];
299   printf ("%.4s\n", buf); // no-warning
300   printf ("%.4s\n", &buf); // expected-warning{{format specifies type 'char *' but the argument has type 'unsigned char (*)[4]'}}
301 
302   // Verify that we are checking asprintf
303   asprintf(&b, "%d", "asprintf"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
304 }
305 
test13(short x)306 void test13(short x) {
307   char bel = 007;
308   printf("bel: '0%hhd'\n", bel); // no-warning
309   printf("x: '0%hhd'\n", x); // expected-warning {{format specifies type 'char' but the argument has type 'short'}}
310 }
311 
312 typedef struct __aslclient *aslclient;
313 typedef struct __aslmsg *aslmsg;
314 int asl_log(aslclient asl, aslmsg msg, int level, const char *format, ...) __attribute__((__format__ (__printf__, 4, 5)));
test_asl(aslclient asl)315 void test_asl(aslclient asl) {
316   // Test case from <rdar://problem/7341605>.
317   asl_log(asl, 0, 3, "Error: %m"); // no-warning
318   asl_log(asl, 0, 3, "Error: %W"); // expected-warning{{invalid conversion specifier 'W'}}
319 }
320 
321 // <rdar://problem/7595366>
322 typedef enum { A } int_t;
f0(int_t x)323 void f0(int_t x) { printf("%d\n", x); }
324 
325 // Unicode test cases.  These are possibly specific to Mac OS X.  If so, they should
326 // eventually be moved into a separate test.
327 
test_unicode_conversions(wchar_t * s)328 void test_unicode_conversions(wchar_t *s) {
329   printf("%S", s); // no-warning
330   printf("%s", s); // expected-warning{{format specifies type 'char *' but the argument has type 'wchar_t *'}}
331   printf("%C", s[0]); // no-warning
332   printf("%c", s[0]);
333   // FIXME: This test reports inconsistent results. On Windows, '%C' expects
334   // 'unsigned short'.
335   // printf("%C", 10);
336   printf("%S", "hello"); // expected-warning{{but the argument has type 'char *'}}
337 }
338 
339 // Mac OS X supports positional arguments in format strings.
340 // This is an IEEE extension (IEEE Std 1003.1).
341 // FIXME: This is probably not portable everywhere.
test_positional_arguments()342 void test_positional_arguments() {
343   printf("%0$", (int)2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
344   printf("%1$*0$d", (int) 2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
345   printf("%1$d", (int) 2); // no-warning
346   printf("%1$d", (int) 2, 2); // expected-warning{{data argument not used by format string}}
347   printf("%1$d%1$f", (int) 2); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
348   printf("%1$2.2d", (int) 2); // no-warning
349   printf("%2$*1$.2d", (int) 2, (int) 3); // no-warning
350   printf("%2$*8$d", (int) 2, (int) 3); // expected-warning{{specified field width is missing a matching 'int' argument}}
351   printf("%%%1$d", (int) 2); // no-warning
352   printf("%1$d%%", (int) 2); // no-warning
353 }
354 
355 // PR 6697 - Handle format strings where the data argument is not adjacent to the format string
356 void myprintf_PR_6697(const char *format, int x, ...) __attribute__((__format__(printf,1, 3)));
test_pr_6697()357 void test_pr_6697() {
358   myprintf_PR_6697("%s\n", 1, "foo"); // no-warning
359   myprintf_PR_6697("%s\n", 1, (int)0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
360   // FIXME: Not everything should clearly support positional arguments,
361   // but we need a way to identify those cases.
362   myprintf_PR_6697("%1$s\n", 1, "foo"); // no-warning
363   myprintf_PR_6697("%2$s\n", 1, "foo"); // expected-warning{{data argument position '2' exceeds the number of data arguments (1)}}
364   myprintf_PR_6697("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (1)}}
365   myprintf_PR_6697("%1$s\n", 1, (int) 0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
366 }
367 
rdar8026030(FILE * fp)368 void rdar8026030(FILE *fp) {
369   fprintf(fp, "\%"); // expected-warning{{incomplete format specifier}}
370 }
371 
bug7377_bad_length_mod_usage()372 void bug7377_bad_length_mod_usage() {
373   // Bad length modifiers
374   printf("%hhs", "foo"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
375   printf("%1$zp", (void *)0); // expected-warning{{length modifier 'z' results in undefined behavior or no effect with 'p' conversion specifier}}
376   printf("%ls", L"foo"); // no-warning
377   printf("%#.2Lf", (long double)1.234); // no-warning
378 
379   // Bad flag usage
380   printf("%#p", (void *) 0); // expected-warning{{flag '#' results in undefined behavior with 'p' conversion specifier}}
381   printf("%0d", -1); // no-warning
382   printf("%#n", (int *) 0); // expected-warning{{flag '#' results in undefined behavior with 'n' conversion specifier}}
383   printf("%-n", (int *) 0); // expected-warning{{flag '-' results in undefined behavior with 'n' conversion specifier}}
384   printf("%-p", (void *) 0); // no-warning
385 
386   // Bad optional amount use
387   printf("%.2c", 'a'); // expected-warning{{precision used with 'c' conversion specifier, resulting in undefined behavior}}
388   printf("%1n", (int *) 0); // expected-warning{{field width used with 'n' conversion specifier, resulting in undefined behavior}}
389   printf("%.9n", (int *) 0); // expected-warning{{precision used with 'n' conversion specifier, resulting in undefined behavior}}
390 
391   // Ignored flags
392   printf("% +f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
393   printf("%+ f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
394   printf("%0-f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
395   printf("%-0f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
396   printf("%-+f", 1.23); // no-warning
397 }
398 
399 // PR 7981 - handle '%lc' (wint_t)
400 
pr7981(wint_t c,wchar_t c2)401 void pr7981(wint_t c, wchar_t c2) {
402   printf("%lc", c); // no-warning
403   printf("%lc", 1.0); // expected-warning{{the argument has type 'double'}}
404   printf("%lc", (char) 1); // no-warning
405   printf("%lc", &c); // expected-warning{{the argument has type 'wint_t *'}}
406   // If wint_t and wchar_t are the same width and wint_t is signed where
407   // wchar_t is unsigned, an implicit conversion isn't possible.
408 #if defined(__WINT_UNSIGNED__) || !defined(__WCHAR_UNSIGNED__) ||   \
409   __WINT_WIDTH__ > __WCHAR_WIDTH__
410   printf("%lc", c2); // no-warning
411 #endif
412 }
413 
414 // <rdar://problem/8269537> -Wformat-security says NULL is not a string literal
rdar8269537()415 void rdar8269537() {
416   // This is likely to crash in most cases, but -Wformat-nonliteral technically
417   // doesn't warn in this case.
418   printf(0); // no-warning
419 }
420 
421 // Handle functions with multiple format attributes.
422 extern void rdar8332221_vprintf_scanf(const char *, va_list, const char *, ...)
423      __attribute__((__format__(__printf__, 1, 0)))
424      __attribute__((__format__(__scanf__, 3, 4)));
425 
rdar8332221(va_list ap,int * x,long * y)426 void rdar8332221(va_list ap, int *x, long *y) {
427   rdar8332221_vprintf_scanf("%", ap, "%d", x); // expected-warning{{incomplete format specifier}}
428 }
429 
430 // PR8641
pr8641()431 void pr8641() {
432   printf("%#x\n", 10);
433   printf("%#X\n", 10);
434 }
435 
posix_extensions()436 void posix_extensions() {
437   // Test %'d, "thousands grouping".
438   // <rdar://problem/8816343>
439   printf("%'d\n", 123456789); // no-warning
440   printf("%'i\n", 123456789); // no-warning
441   printf("%'f\n", (float) 1.0); // no-warning
442   printf("%'p\n", (void*) 0); // expected-warning{{results in undefined behavior with 'p' conversion specifier}}
443 }
444 
445 // PR8486
446 //
447 // Test what happens when -Wformat is on, but -Wformat-security is off.
448 #pragma GCC diagnostic warning "-Wformat"
449 #pragma GCC diagnostic ignored "-Wformat-security"
450 
pr8486()451 void pr8486() {
452   printf("%s", 1); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
453 }
454 
455 // PR9314
456 // Don't warn about string literals that are PreDefinedExprs, e.g. __func__.
pr9314()457 void pr9314() {
458   printf(__PRETTY_FUNCTION__); // no-warning
459   printf(__func__); // no-warning
460 }
461 
462 int printf(const char * restrict, ...) __attribute__((__format__ (__printf__, 1, 2)));
463 
rdar9612060(void)464 void rdar9612060(void) {
465   printf("%s", 2); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
466 }
467 
check_char(unsigned char x,signed char y)468 void check_char(unsigned char x, signed char y) {
469   printf("%c", y); // no-warning
470   printf("%hhu", x); // no-warning
471   printf("%hhi", y); // no-warning
472   printf("%hhi", x); // no-warning
473   printf("%c", x); // no-warning
474   printf("%hhu", y); // no-warning
475 }
476 
477 // Test suppression of individual warnings.
478 
test_suppress_invalid_specifier()479 void test_suppress_invalid_specifier() {
480 #pragma clang diagnostic push
481 #pragma clang diagnostic ignored "-Wformat-invalid-specifier"
482   printf("%@", 12); // no-warning
483 #pragma clang diagnostic pop
484 }
485 
486 // Make sure warnings are on for next test.
487 #pragma GCC diagnostic warning "-Wformat"
488 #pragma GCC diagnostic warning "-Wformat-security"
489 
490 // Test that the printf call site is where the warning is attached.  If the
491 // format string is somewhere else, point to it in a note.
pr9751()492 void pr9751() {
493   const char kFormat1[] = "%d %d \n"; // expected-note{{format string is defined here}}}
494   printf(kFormat1, 0); // expected-warning{{more '%' conversions than data arguments}}
495   printf("%d %s\n", 0); // expected-warning{{more '%' conversions than data arguments}}
496 
497   const char kFormat2[] = "%18$s\n"; // expected-note{{format string is defined here}}
498   printf(kFormat2, 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
499   printf("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
500 
501   const char kFormat4[] = "%y"; // expected-note{{format string is defined here}}
502   printf(kFormat4, 5); // expected-warning{{invalid conversion specifier 'y'}}
503   printf("%y", 5); // expected-warning{{invalid conversion specifier 'y'}}
504 
505   const char kFormat5[] = "%."; // expected-note{{format string is defined here}}
506   printf(kFormat5, 5); // expected-warning{{incomplete format specifier}}
507   printf("%.", 5); // expected-warning{{incomplete format specifier}}
508 
509   const char kFormat6[] = "%s"; // expected-note{{format string is defined here}}
510   printf(kFormat6, 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
511   printf("%s", 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
512 
513   const char kFormat7[] = "%0$"; // expected-note{{format string is defined here}}
514   printf(kFormat7, 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
515   printf("%0$", 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
516 
517   const char kFormat8[] = "%1$d %d"; // expected-note{{format string is defined here}}
518   printf(kFormat8, 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
519   printf("%1$d %d", 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
520 
521   const char kFormat9[] = ""; // expected-note{{format string is defined here}}
522   printf(kFormat9, 4, 4); // expected-warning{{format string is empty}}
523   printf("", 4, 4); // expected-warning{{format string is empty}}
524 
525   const char kFormat10[] = "\0%d"; // expected-note{{format string is defined here}}
526   printf(kFormat10, 4); // expected-warning{{format string contains '\0' within the string body}}
527   printf("\0%d", 4); // expected-warning{{format string contains '\0' within the string body}}
528 
529   const char kFormat11[] = "%*d"; // expected-note{{format string is defined here}}
530   printf(kFormat11); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
531   printf("%*d"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
532 
533   const char kFormat12[] = "%*d"; // expected-note{{format string is defined here}}
534   printf(kFormat12, 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
535   printf("%*d", 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
536 
537   const char kFormat13[] = "%.3p"; // expected-note{{format string is defined here}}
538   void *p;
539   printf(kFormat13, p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
540   printf("%.3p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
541 
542   const char kFormat14[] = "%0s"; // expected-note{{format string is defined here}}
543   printf(kFormat14, "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
544   printf("%0s", "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
545 
546   const char kFormat15[] = "%hhs"; // expected-note{{format string is defined here}}
547   printf(kFormat15, "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
548   printf("%hhs", "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
549 
550   const char kFormat16[] = "%-0d"; // expected-note{{format string is defined here}}
551   printf(kFormat16, 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
552   printf("%-0d", 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
553 
554   // Make sure that the "format string is defined here" note is not emitted
555   // when the original string is within the argument expression.
556   printf(1 ? "yes %d" : "no %d"); // expected-warning{{more '%' conversions than data arguments}}
557 
558   const char kFormat17[] = "%hu"; // expected-note{{format string is defined here}}}
559   printf(kFormat17, (int[]){0}); // expected-warning{{format specifies type 'unsigned short' but the argument}}
560 
561   printf("%a", (long double)0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
562 
563   // Test braced char[] initializers.
564   const char kFormat18[] = { "%lld" }; // expected-note{{format string is defined here}}
565   printf(kFormat18, 0); // expected-warning{{format specifies type}}
566 
567   // Make sure we point at the offending argument rather than the format string.
568   const char kFormat19[] = "%d";  // expected-note{{format string is defined here}}
569   printf(kFormat19,
570          0.0); // expected-warning{{format specifies}}
571 }
572 
pr18905()573 void pr18905() {
574   const char s1[] = "s\0%s"; // expected-note{{format string is defined here}}
575   const char s2[1] = "s"; // expected-note{{format string is defined here}}
576   const char s3[2] = "s\0%s"; // expected-warning{{initializer-string for char array is too long}}
577   const char s4[10] = "s";
578   const char s5[0] = "%s"; // expected-warning{{initializer-string for char array is too long}}
579                            // expected-note@-1{{format string is defined here}}
580 
581   printf(s1); // expected-warning{{format string contains '\0' within the string body}}
582   printf(s2); // expected-warning{{format string is not null-terminated}}
583   printf(s3); // no-warning
584   printf(s4); // no-warning
585   printf(s5); // expected-warning{{format string is not null-terminated}}
586 }
587 
588 void __attribute__((format(strfmon,1,2))) monformat(const char *fmt, ...);
589 void __attribute__((format(strftime,1,0))) dateformat(const char *fmt);
590 
591 // Other formats
test_other_formats()592 void test_other_formats() {
593   char *str = "";
594   monformat("", 1); // expected-warning{{format string is empty}}
595   monformat(str); // expected-warning{{format string is not a string literal (potentially insecure)}}
596   dateformat(""); // expected-warning{{format string is empty}}
597   dateformat(str); // no-warning (using strftime non-literal is not unsafe)
598 }
599 
600 // Do not warn about unused arguments coming from system headers.
601 // <rdar://problem/11317765>
602 #include <format-unused-system-args.h>
test_unused_system_args(int x)603 void test_unused_system_args(int x) {
604   PRINT1("%d\n", x); // no-warning{{extra argument is system header is OK}}
605 }
606 
pr12761(char c)607 void pr12761(char c) {
608   // This should not warn even with -fno-signed-char.
609   printf("%hhx", c);
610 }
611 
612 
613 // Test that we correctly merge the format in both orders.
614 extern void test14_foo(const char *, const char *, ...)
615      __attribute__((__format__(__printf__, 1, 3)));
616 extern void test14_foo(const char *, const char *, ...)
617      __attribute__((__format__(__scanf__, 2, 3)));
618 
619 extern void test14_bar(const char *, const char *, ...)
620      __attribute__((__format__(__scanf__, 2, 3)));
621 extern void test14_bar(const char *, const char *, ...)
622      __attribute__((__format__(__printf__, 1, 3)));
623 
test14_zed(int * p)624 void test14_zed(int *p) {
625   test14_foo("%", "%d", p); // expected-warning{{incomplete format specifier}}
626   test14_bar("%", "%d", p); // expected-warning{{incomplete format specifier}}
627 }
628 
test_qualifiers(volatile int * vip,const int * cip,const volatile int * cvip)629 void test_qualifiers(volatile int *vip, const int *cip,
630                      const volatile int *cvip) {
631   printf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
632   printf("%n", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
633 
634   printf("%n", vip); // No warning.
635   printf("%p", cip); // No warning.
636   printf("%p", cvip); // No warning.
637 
638 
639   typedef int* ip_t;
640   typedef const int* cip_t;
641   printf("%n", (ip_t)0); // No warning.
642   printf("%n", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
643 }
644 
645 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
646 #pragma GCC diagnostic warning "-Wformat-security"
647 // <rdar://problem/14178260>
648 extern void test_format_security_extra_args(const char*, int, ...)
649     __attribute__((__format__(__printf__, 1, 3)));
test_format_security_pos(char * string)650 void test_format_security_pos(char* string) {
651   test_format_security_extra_args(string, 5); // expected-warning {{format string is not a string literal (potentially insecure)}}
652   // expected-note@-1{{treat the string as an argument to avoid this}}
653 }
654 #pragma GCC diagnostic warning "-Wformat-nonliteral"
655