1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "base/strings/safe_sprintf.h"
6 
7 #include <stddef.h>
8 #include <stdint.h>
9 #include <stdio.h>
10 #include <string.h>
11 
12 #include <limits>
13 #include <memory>
14 
15 #include "base/logging.h"
16 #include "base/macros.h"
17 #include "build/build_config.h"
18 #include "testing/gtest/include/gtest/gtest.h"
19 
20 // Death tests on Android are currently very flaky. No need to add more flaky
21 // tests, as they just make it hard to spot real problems.
22 // TODO(markus): See if the restrictions on Android can eventually be lifted.
23 #if defined(GTEST_HAS_DEATH_TEST) && !defined(OS_ANDROID)
24 #define ALLOW_DEATH_TEST
25 #endif
26 
27 namespace base {
28 namespace strings {
29 
TEST(SafeSPrintfTest,Empty)30 TEST(SafeSPrintfTest, Empty) {
31   char buf[2] = { 'X', 'X' };
32 
33   // Negative buffer size should always result in an error.
34   EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), ""));
35   EXPECT_EQ('X', buf[0]);
36   EXPECT_EQ('X', buf[1]);
37 
38   // Zero buffer size should always result in an error.
39   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, ""));
40   EXPECT_EQ('X', buf[0]);
41   EXPECT_EQ('X', buf[1]);
42 
43   // A one-byte buffer should always print a single NUL byte.
44   EXPECT_EQ(0, SafeSNPrintf(buf, 1, ""));
45   EXPECT_EQ(0, buf[0]);
46   EXPECT_EQ('X', buf[1]);
47   buf[0] = 'X';
48 
49   // A larger buffer should leave the trailing bytes unchanged.
50   EXPECT_EQ(0, SafeSNPrintf(buf, 2, ""));
51   EXPECT_EQ(0, buf[0]);
52   EXPECT_EQ('X', buf[1]);
53   buf[0] = 'X';
54 
55   // The same test using SafeSPrintf() instead of SafeSNPrintf().
56   EXPECT_EQ(0, SafeSPrintf(buf, ""));
57   EXPECT_EQ(0, buf[0]);
58   EXPECT_EQ('X', buf[1]);
59   buf[0] = 'X';
60 }
61 
TEST(SafeSPrintfTest,NoArguments)62 TEST(SafeSPrintfTest, NoArguments) {
63   // Output a text message that doesn't require any substitutions. This
64   // is roughly equivalent to calling strncpy() (but unlike strncpy(), it does
65   // always add a trailing NUL; it always deduplicates '%' characters).
66   static const char text[] = "hello world";
67   char ref[20], buf[20];
68   memset(ref, 'X', sizeof(ref));
69   memcpy(buf, ref, sizeof(buf));
70 
71   // A negative buffer size should always result in an error.
72   EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), text));
73   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
74 
75   // Zero buffer size should always result in an error.
76   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, text));
77   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
78 
79   // A one-byte buffer should always print a single NUL byte.
80   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 1, text));
81   EXPECT_EQ(0, buf[0]);
82   EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
83   memcpy(buf, ref, sizeof(buf));
84 
85   // A larger (but limited) buffer should always leave the trailing bytes
86   // unchanged.
87   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 2, text));
88   EXPECT_EQ(text[0], buf[0]);
89   EXPECT_EQ(0, buf[1]);
90   EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
91   memcpy(buf, ref, sizeof(buf));
92 
93   // A unrestricted buffer length should always leave the trailing bytes
94   // unchanged.
95   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
96             SafeSNPrintf(buf, sizeof(buf), text));
97   EXPECT_EQ(std::string(text), std::string(buf));
98   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
99                       sizeof(buf) - sizeof(text)));
100   memcpy(buf, ref, sizeof(buf));
101 
102   // The same test using SafeSPrintf() instead of SafeSNPrintf().
103   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, text));
104   EXPECT_EQ(std::string(text), std::string(buf));
105   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
106                       sizeof(buf) - sizeof(text)));
107   memcpy(buf, ref, sizeof(buf));
108 
109   // Check for deduplication of '%' percent characters.
110   EXPECT_EQ(1, SafeSPrintf(buf, "%%"));
111   EXPECT_EQ(2, SafeSPrintf(buf, "%%%%"));
112   EXPECT_EQ(2, SafeSPrintf(buf, "%%X"));
113   EXPECT_EQ(3, SafeSPrintf(buf, "%%%%X"));
114 #if defined(NDEBUG)
115   EXPECT_EQ(1, SafeSPrintf(buf, "%"));
116   EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
117   EXPECT_EQ(2, SafeSPrintf(buf, "%X"));
118   EXPECT_EQ(3, SafeSPrintf(buf, "%%%X"));
119 #elif defined(ALLOW_DEATH_TEST)
120   EXPECT_DEATH(SafeSPrintf(buf, "%"), "src.1. == '%'");
121   EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
122   EXPECT_DEATH(SafeSPrintf(buf, "%X"), "src.1. == '%'");
123   EXPECT_DEATH(SafeSPrintf(buf, "%%%X"), "src.1. == '%'");
124 #endif
125 }
126 
TEST(SafeSPrintfTest,OneArgument)127 TEST(SafeSPrintfTest, OneArgument) {
128   // Test basic single-argument single-character substitution.
129   const char text[] = "hello world";
130   const char fmt[]  = "hello%cworld";
131   char ref[20], buf[20];
132   memset(ref, 'X', sizeof(buf));
133   memcpy(buf, ref, sizeof(buf));
134 
135   // A negative buffer size should always result in an error.
136   EXPECT_EQ(-1, SafeSNPrintf(buf, static_cast<size_t>(-1), fmt, ' '));
137   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
138 
139   // Zero buffer size should always result in an error.
140   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, fmt, ' '));
141   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
142 
143   // A one-byte buffer should always print a single NUL byte.
144   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
145             SafeSNPrintf(buf, 1, fmt, ' '));
146   EXPECT_EQ(0, buf[0]);
147   EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
148   memcpy(buf, ref, sizeof(buf));
149 
150   // A larger (but limited) buffer should always leave the trailing bytes
151   // unchanged.
152   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
153             SafeSNPrintf(buf, 2, fmt, ' '));
154   EXPECT_EQ(text[0], buf[0]);
155   EXPECT_EQ(0, buf[1]);
156   EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
157   memcpy(buf, ref, sizeof(buf));
158 
159   // A unrestricted buffer length should always leave the trailing bytes
160   // unchanged.
161   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
162             SafeSNPrintf(buf, sizeof(buf), fmt, ' '));
163   EXPECT_EQ(std::string(text), std::string(buf));
164   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
165                       sizeof(buf) - sizeof(text)));
166   memcpy(buf, ref, sizeof(buf));
167 
168   // The same test using SafeSPrintf() instead of SafeSNPrintf().
169   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, fmt, ' '));
170   EXPECT_EQ(std::string(text), std::string(buf));
171   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
172                       sizeof(buf) - sizeof(text)));
173   memcpy(buf, ref, sizeof(buf));
174 
175   // Check for deduplication of '%' percent characters.
176   EXPECT_EQ(1, SafeSPrintf(buf, "%%", 0));
177   EXPECT_EQ(2, SafeSPrintf(buf, "%%%%", 0));
178   EXPECT_EQ(2, SafeSPrintf(buf, "%Y", 0));
179   EXPECT_EQ(2, SafeSPrintf(buf, "%%Y", 0));
180   EXPECT_EQ(3, SafeSPrintf(buf, "%%%Y", 0));
181   EXPECT_EQ(3, SafeSPrintf(buf, "%%%%Y", 0));
182 #if defined(NDEBUG)
183   EXPECT_EQ(1, SafeSPrintf(buf, "%", 0));
184   EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
185 #elif defined(ALLOW_DEATH_TEST)
186   EXPECT_DEATH(SafeSPrintf(buf, "%", 0), "ch");
187   EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
188 #endif
189 }
190 
TEST(SafeSPrintfTest,MissingArg)191 TEST(SafeSPrintfTest, MissingArg) {
192 #if defined(NDEBUG)
193   char buf[20];
194   EXPECT_EQ(3, SafeSPrintf(buf, "%c%c", 'A'));
195   EXPECT_EQ("A%c", std::string(buf));
196 #elif defined(ALLOW_DEATH_TEST)
197   char buf[20];
198   EXPECT_DEATH(SafeSPrintf(buf, "%c%c", 'A'), "cur_arg < max_args");
199 #endif
200 }
201 
TEST(SafeSPrintfTest,ASANFriendlyBufferTest)202 TEST(SafeSPrintfTest, ASANFriendlyBufferTest) {
203   // Print into a buffer that is sized exactly to size. ASAN can verify that
204   // nobody attempts to write past the end of the buffer.
205   // There is a more complicated test in PrintLongString() that covers a lot
206   // more edge case, but it is also harder to debug in case of a failure.
207   const char kTestString[] = "This is a test";
208   std::unique_ptr<char[]> buf(new char[sizeof(kTestString)]);
209   EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
210             SafeSNPrintf(buf.get(), sizeof(kTestString), kTestString));
211   EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
212   EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
213             SafeSNPrintf(buf.get(), sizeof(kTestString), "%s", kTestString));
214   EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
215 }
216 
TEST(SafeSPrintfTest,NArgs)217 TEST(SafeSPrintfTest, NArgs) {
218   // Pre-C++11 compilers have a different code path, that can only print
219   // up to ten distinct arguments.
220   // We test both SafeSPrintf() and SafeSNPrintf(). This makes sure we don't
221   // have typos in the copy-n-pasted code that is needed to deal with various
222   // numbers of arguments.
223   char buf[12];
224   EXPECT_EQ(1, SafeSPrintf(buf, "%c", 1));
225   EXPECT_EQ("\1", std::string(buf));
226   EXPECT_EQ(2, SafeSPrintf(buf, "%c%c", 1, 2));
227   EXPECT_EQ("\1\2", std::string(buf));
228   EXPECT_EQ(3, SafeSPrintf(buf, "%c%c%c", 1, 2, 3));
229   EXPECT_EQ("\1\2\3", std::string(buf));
230   EXPECT_EQ(4, SafeSPrintf(buf, "%c%c%c%c", 1, 2, 3, 4));
231   EXPECT_EQ("\1\2\3\4", std::string(buf));
232   EXPECT_EQ(5, SafeSPrintf(buf, "%c%c%c%c%c", 1, 2, 3, 4, 5));
233   EXPECT_EQ("\1\2\3\4\5", std::string(buf));
234   EXPECT_EQ(6, SafeSPrintf(buf, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
235   EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
236   EXPECT_EQ(7, SafeSPrintf(buf, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
237   EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
238   EXPECT_EQ(8, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7, 8));
239   EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
240   EXPECT_EQ(9, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c",
241                            1, 2, 3, 4, 5, 6, 7, 8, 9));
242   EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
243   EXPECT_EQ(10, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c%c",
244                             1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
245 
246   // Repeat all the tests with SafeSNPrintf() instead of SafeSPrintf().
247   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
248   EXPECT_EQ(1, SafeSNPrintf(buf, 11, "%c", 1));
249   EXPECT_EQ("\1", std::string(buf));
250   EXPECT_EQ(2, SafeSNPrintf(buf, 11, "%c%c", 1, 2));
251   EXPECT_EQ("\1\2", std::string(buf));
252   EXPECT_EQ(3, SafeSNPrintf(buf, 11, "%c%c%c", 1, 2, 3));
253   EXPECT_EQ("\1\2\3", std::string(buf));
254   EXPECT_EQ(4, SafeSNPrintf(buf, 11, "%c%c%c%c", 1, 2, 3, 4));
255   EXPECT_EQ("\1\2\3\4", std::string(buf));
256   EXPECT_EQ(5, SafeSNPrintf(buf, 11, "%c%c%c%c%c", 1, 2, 3, 4, 5));
257   EXPECT_EQ("\1\2\3\4\5", std::string(buf));
258   EXPECT_EQ(6, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
259   EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
260   EXPECT_EQ(7, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
261   EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
262   EXPECT_EQ(8, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c",
263                             1, 2, 3, 4, 5, 6, 7, 8));
264   EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
265   EXPECT_EQ(9, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c",
266                             1, 2, 3, 4, 5, 6, 7, 8, 9));
267   EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
268   EXPECT_EQ(10, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c%c",
269                              1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
270   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
271 
272   EXPECT_EQ(11, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c%c%c",
273                             1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11));
274   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12\13", std::string(buf));
275   EXPECT_EQ(11, SafeSNPrintf(buf, 12, "%c%c%c%c%c%c%c%c%c%c%c",
276                              1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11));
277   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12\13", std::string(buf));
278 }
279 
TEST(SafeSPrintfTest,DataTypes)280 TEST(SafeSPrintfTest, DataTypes) {
281   char buf[40];
282 
283   // Bytes
284   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint8_t)1));
285   EXPECT_EQ("1", std::string(buf));
286   EXPECT_EQ(3, SafeSPrintf(buf, "%d", (uint8_t)-1));
287   EXPECT_EQ("255", std::string(buf));
288   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int8_t)1));
289   EXPECT_EQ("1", std::string(buf));
290   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int8_t)-1));
291   EXPECT_EQ("-1", std::string(buf));
292   EXPECT_EQ(4, SafeSPrintf(buf, "%d", (int8_t)-128));
293   EXPECT_EQ("-128", std::string(buf));
294 
295   // Half-words
296   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint16_t)1));
297   EXPECT_EQ("1", std::string(buf));
298   EXPECT_EQ(5, SafeSPrintf(buf, "%d", (uint16_t)-1));
299   EXPECT_EQ("65535", std::string(buf));
300   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int16_t)1));
301   EXPECT_EQ("1", std::string(buf));
302   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int16_t)-1));
303   EXPECT_EQ("-1", std::string(buf));
304   EXPECT_EQ(6, SafeSPrintf(buf, "%d", (int16_t)-32768));
305   EXPECT_EQ("-32768", std::string(buf));
306 
307   // Words
308   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint32_t)1));
309   EXPECT_EQ("1", std::string(buf));
310   EXPECT_EQ(10, SafeSPrintf(buf, "%d", (uint32_t)-1));
311   EXPECT_EQ("4294967295", std::string(buf));
312   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int32_t)1));
313   EXPECT_EQ("1", std::string(buf));
314   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int32_t)-1));
315   EXPECT_EQ("-1", std::string(buf));
316   // Work-around for an limitation of C90
317   EXPECT_EQ(11, SafeSPrintf(buf, "%d", (int32_t)-2147483647-1));
318   EXPECT_EQ("-2147483648", std::string(buf));
319 
320   // Quads
321   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint64_t)1));
322   EXPECT_EQ("1", std::string(buf));
323   EXPECT_EQ(20, SafeSPrintf(buf, "%d", (uint64_t)-1));
324   EXPECT_EQ("18446744073709551615", std::string(buf));
325   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int64_t)1));
326   EXPECT_EQ("1", std::string(buf));
327   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int64_t)-1));
328   EXPECT_EQ("-1", std::string(buf));
329   // Work-around for an limitation of C90
330   EXPECT_EQ(20, SafeSPrintf(buf, "%d", (int64_t)-9223372036854775807LL-1));
331   EXPECT_EQ("-9223372036854775808", std::string(buf));
332 
333   // Strings (both const and mutable).
334   EXPECT_EQ(4, SafeSPrintf(buf, "test"));
335   EXPECT_EQ("test", std::string(buf));
336   EXPECT_EQ(4, SafeSPrintf(buf, buf));
337   EXPECT_EQ("test", std::string(buf));
338 
339   // Pointer
340   char addr[20];
341   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
342   SafeSPrintf(buf, "%p", buf);
343   EXPECT_EQ(std::string(addr), std::string(buf));
344   SafeSPrintf(buf, "%p", (const char *)buf);
345   EXPECT_EQ(std::string(addr), std::string(buf));
346   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)sprintf);
347   SafeSPrintf(buf, "%p", sprintf);
348   EXPECT_EQ(std::string(addr), std::string(buf));
349 
350   // Padding for pointers is a little more complicated because of the "0x"
351   // prefix. Padding with '0' zeros is relatively straight-forward, but
352   // padding with ' ' spaces requires more effort.
353   sprintf(addr, "0x%017llX", (unsigned long long)(uintptr_t)buf);
354   SafeSPrintf(buf, "%019p", buf);
355   EXPECT_EQ(std::string(addr), std::string(buf));
356   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
357   memset(addr, ' ',
358          (char*)memmove(addr + sizeof(addr) - strlen(addr) - 1,
359                         addr, strlen(addr)+1) - addr);
360   SafeSPrintf(buf, "%19p", buf);
361   EXPECT_EQ(std::string(addr), std::string(buf));
362 }
363 
364 namespace {
PrintLongString(char * buf,size_t sz)365 void PrintLongString(char* buf, size_t sz) {
366   // Output a reasonably complex expression into a limited-size buffer.
367   // At least one byte is available for writing the NUL character.
368   CHECK_GT(sz, static_cast<size_t>(0));
369 
370   // Allocate slightly more space, so that we can verify that SafeSPrintf()
371   // never writes past the end of the buffer.
372   std::unique_ptr<char[]> tmp(new char[sz + 2]);
373   memset(tmp.get(), 'X', sz+2);
374 
375   // Use SafeSPrintf() to output a complex list of arguments:
376   // - test padding and truncating %c single characters.
377   // - test truncating %s simple strings.
378   // - test mismatching arguments and truncating (for %d != %s).
379   // - test zero-padding and truncating %x hexadecimal numbers.
380   // - test outputting and truncating %d MININT.
381   // - test outputting and truncating %p arbitrary pointer values.
382   // - test outputting, padding and truncating NULL-pointer %s strings.
383   char* out = tmp.get();
384   size_t out_sz = sz;
385   size_t len;
386   for (std::unique_ptr<char[]> perfect_buf;;) {
387     size_t needed =
388         SafeSNPrintf(out, out_sz,
389 #if defined(NDEBUG)
390                      "A%2cong %s: %d %010X %d %p%7s", 'l', "string", "",
391 #else
392                      "A%2cong %s: %%d %010X %d %p%7s", 'l', "string",
393 #endif
394                      0xDEADBEEF, std::numeric_limits<intptr_t>::min(),
395                      PrintLongString, static_cast<char*>(nullptr)) +
396         1;
397 
398     // Various sanity checks:
399     // The numbered of characters needed to print the full string should always
400     // be bigger or equal to the bytes that have actually been output.
401     len = strlen(tmp.get());
402     CHECK_GE(needed, len+1);
403 
404     // The number of characters output should always fit into the buffer that
405     // was passed into SafeSPrintf().
406     CHECK_LT(len, out_sz);
407 
408     // The output is always terminated with a NUL byte (actually, this test is
409     // always going to pass, as strlen() already verified this)
410     EXPECT_FALSE(tmp[len]);
411 
412     // ASAN can check that we are not overwriting buffers, iff we make sure the
413     // buffer is exactly the size that we are expecting to be written. After
414     // running SafeSNPrintf() the first time, it is possible to compute the
415     // correct buffer size for this test. So, allocate a second buffer and run
416     // the exact same SafeSNPrintf() command again.
417     if (!perfect_buf.get()) {
418       out_sz = std::min(needed, sz);
419       out = new char[out_sz];
420       perfect_buf.reset(out);
421     } else {
422       break;
423     }
424   }
425 
426   // All trailing bytes are unchanged.
427   for (size_t i = len+1; i < sz+2; ++i)
428     EXPECT_EQ('X', tmp[i]);
429 
430   // The text that was generated by SafeSPrintf() should always match the
431   // equivalent text generated by sprintf(). Please note that the format
432   // string for sprintf() is not complicated, as it does not have the
433   // benefit of getting type information from the C++ compiler.
434   //
435   // N.B.: It would be so much cleaner to use snprintf(). But unfortunately,
436   //       Visual Studio doesn't support this function, and the work-arounds
437   //       are all really awkward.
438   char ref[256];
439   CHECK_LE(sz, sizeof(ref));
440   sprintf(ref, "A long string: %%d 00DEADBEEF %lld 0x%llX <NULL>",
441           static_cast<long long>(std::numeric_limits<intptr_t>::min()),
442           static_cast<unsigned long long>(
443             reinterpret_cast<uintptr_t>(PrintLongString)));
444   ref[sz-1] = '\000';
445 
446 #if defined(NDEBUG)
447   const size_t kSSizeMax = std::numeric_limits<ssize_t>::max();
448 #else
449   const size_t kSSizeMax = internal::GetSafeSPrintfSSizeMaxForTest();
450 #endif
451 
452   // Compare the output from SafeSPrintf() to the one from sprintf().
453   EXPECT_EQ(std::string(ref).substr(0, kSSizeMax-1), std::string(tmp.get()));
454 
455   // We allocated a slightly larger buffer, so that we could perform some
456   // extra sanity checks. Now that the tests have all passed, we copy the
457   // data to the output buffer that the caller provided.
458   memcpy(buf, tmp.get(), len+1);
459 }
460 
461 #if !defined(NDEBUG)
462 class ScopedSafeSPrintfSSizeMaxSetter {
463  public:
ScopedSafeSPrintfSSizeMaxSetter(size_t sz)464   ScopedSafeSPrintfSSizeMaxSetter(size_t sz) {
465     old_ssize_max_ = internal::GetSafeSPrintfSSizeMaxForTest();
466     internal::SetSafeSPrintfSSizeMaxForTest(sz);
467   }
468 
~ScopedSafeSPrintfSSizeMaxSetter()469   ~ScopedSafeSPrintfSSizeMaxSetter() {
470     internal::SetSafeSPrintfSSizeMaxForTest(old_ssize_max_);
471   }
472 
473  private:
474   size_t old_ssize_max_;
475 
476   DISALLOW_COPY_AND_ASSIGN(ScopedSafeSPrintfSSizeMaxSetter);
477 };
478 #endif
479 
480 }  // anonymous namespace
481 
TEST(SafeSPrintfTest,Truncation)482 TEST(SafeSPrintfTest, Truncation) {
483   // We use PrintLongString() to print a complex long string and then
484   // truncate to all possible lengths. This ends up exercising a lot of
485   // different code paths in SafeSPrintf() and IToASCII(), as truncation can
486   // happen in a lot of different states.
487   char ref[256];
488   PrintLongString(ref, sizeof(ref));
489   for (size_t i = strlen(ref)+1; i; --i) {
490     char buf[sizeof(ref)];
491     PrintLongString(buf, i);
492     EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
493   }
494 
495   // When compiling in debug mode, we have the ability to fake a small
496   // upper limit for the maximum value that can be stored in an ssize_t.
497   // SafeSPrintf() uses this upper limit to determine how many bytes it will
498   // write to the buffer, even if the caller claimed a bigger buffer size.
499   // Repeat the truncation test and verify that this other code path in
500   // SafeSPrintf() works correctly, too.
501 #if !defined(NDEBUG)
502   for (size_t i = strlen(ref)+1; i > 1; --i) {
503     ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(i);
504     char buf[sizeof(ref)];
505     PrintLongString(buf, sizeof(buf));
506     EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
507   }
508 
509   // kSSizeMax is also used to constrain the maximum amount of padding, before
510   // SafeSPrintf() detects an error in the format string.
511   ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(100);
512   char buf[256];
513   EXPECT_EQ(99, SafeSPrintf(buf, "%99c", ' '));
514   EXPECT_EQ(std::string(99, ' '), std::string(buf));
515   *buf = '\000';
516 #if defined(ALLOW_DEATH_TEST)
517   EXPECT_DEATH(SafeSPrintf(buf, "%100c", ' '), "padding <= max_padding");
518 #endif
519   EXPECT_EQ(0, *buf);
520 #endif
521 }
522 
TEST(SafeSPrintfTest,Padding)523 TEST(SafeSPrintfTest, Padding) {
524   char buf[40], fmt[40];
525 
526   // Chars %c
527   EXPECT_EQ(1, SafeSPrintf(buf, "%c", 'A'));
528   EXPECT_EQ("A", std::string(buf));
529   EXPECT_EQ(2, SafeSPrintf(buf, "%2c", 'A'));
530   EXPECT_EQ(" A", std::string(buf));
531   EXPECT_EQ(2, SafeSPrintf(buf, "%02c", 'A'));
532   EXPECT_EQ(" A", std::string(buf));
533   EXPECT_EQ(4, SafeSPrintf(buf, "%-2c", 'A'));
534   EXPECT_EQ("%-2c", std::string(buf));
535   SafeSPrintf(fmt, "%%%dc", std::numeric_limits<ssize_t>::max() - 1);
536   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1, SafeSPrintf(buf, fmt, 'A'));
537   SafeSPrintf(fmt, "%%%dc",
538               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
539 #if defined(NDEBUG)
540   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 'A'));
541   EXPECT_EQ("%c", std::string(buf));
542 #elif defined(ALLOW_DEATH_TEST)
543   EXPECT_DEATH(SafeSPrintf(buf, fmt, 'A'), "padding <= max_padding");
544 #endif
545 
546   // Octal %o
547   EXPECT_EQ(1, SafeSPrintf(buf, "%o", 1));
548   EXPECT_EQ("1", std::string(buf));
549   EXPECT_EQ(2, SafeSPrintf(buf, "%2o", 1));
550   EXPECT_EQ(" 1", std::string(buf));
551   EXPECT_EQ(2, SafeSPrintf(buf, "%02o", 1));
552   EXPECT_EQ("01", std::string(buf));
553   EXPECT_EQ(12, SafeSPrintf(buf, "%12o", -1));
554   EXPECT_EQ(" 37777777777", std::string(buf));
555   EXPECT_EQ(12, SafeSPrintf(buf, "%012o", -1));
556   EXPECT_EQ("037777777777", std::string(buf));
557   EXPECT_EQ(23, SafeSPrintf(buf, "%23o", -1LL));
558   EXPECT_EQ(" 1777777777777777777777", std::string(buf));
559   EXPECT_EQ(23, SafeSPrintf(buf, "%023o", -1LL));
560   EXPECT_EQ("01777777777777777777777", std::string(buf));
561   EXPECT_EQ(3, SafeSPrintf(buf, "%2o", 0111));
562   EXPECT_EQ("111", std::string(buf));
563   EXPECT_EQ(4, SafeSPrintf(buf, "%-2o", 1));
564   EXPECT_EQ("%-2o", std::string(buf));
565   SafeSPrintf(fmt, "%%%do", std::numeric_limits<ssize_t>::max()-1);
566   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
567             SafeSNPrintf(buf, 4, fmt, 1));
568   EXPECT_EQ("   ", std::string(buf));
569   SafeSPrintf(fmt, "%%0%do", std::numeric_limits<ssize_t>::max()-1);
570   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
571             SafeSNPrintf(buf, 4, fmt, 1));
572   EXPECT_EQ("000", std::string(buf));
573   SafeSPrintf(fmt, "%%%do",
574               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
575 #if defined(NDEBUG)
576   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
577   EXPECT_EQ("%o", std::string(buf));
578 #elif defined(ALLOW_DEATH_TEST)
579   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
580 #endif
581 
582   // Decimals %d
583   EXPECT_EQ(1, SafeSPrintf(buf, "%d", 1));
584   EXPECT_EQ("1", std::string(buf));
585   EXPECT_EQ(2, SafeSPrintf(buf, "%2d", 1));
586   EXPECT_EQ(" 1", std::string(buf));
587   EXPECT_EQ(2, SafeSPrintf(buf, "%02d", 1));
588   EXPECT_EQ("01", std::string(buf));
589   EXPECT_EQ(3, SafeSPrintf(buf, "%3d", -1));
590   EXPECT_EQ(" -1", std::string(buf));
591   EXPECT_EQ(3, SafeSPrintf(buf, "%03d", -1));
592   EXPECT_EQ("-01", std::string(buf));
593   EXPECT_EQ(3, SafeSPrintf(buf, "%2d", 111));
594   EXPECT_EQ("111", std::string(buf));
595   EXPECT_EQ(4, SafeSPrintf(buf, "%2d", -111));
596   EXPECT_EQ("-111", std::string(buf));
597   EXPECT_EQ(4, SafeSPrintf(buf, "%-2d", 1));
598   EXPECT_EQ("%-2d", std::string(buf));
599   SafeSPrintf(fmt, "%%%dd", std::numeric_limits<ssize_t>::max()-1);
600   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
601             SafeSNPrintf(buf, 4, fmt, 1));
602   EXPECT_EQ("   ", std::string(buf));
603   SafeSPrintf(fmt, "%%0%dd", std::numeric_limits<ssize_t>::max()-1);
604   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
605             SafeSNPrintf(buf, 4, fmt, 1));
606   EXPECT_EQ("000", std::string(buf));
607   SafeSPrintf(fmt, "%%%dd",
608               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
609 #if defined(NDEBUG)
610   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
611   EXPECT_EQ("%d", std::string(buf));
612 #elif defined(ALLOW_DEATH_TEST)
613   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
614 #endif
615 
616   // Hex %X
617   EXPECT_EQ(1, SafeSPrintf(buf, "%X", 1));
618   EXPECT_EQ("1", std::string(buf));
619   EXPECT_EQ(2, SafeSPrintf(buf, "%2X", 1));
620   EXPECT_EQ(" 1", std::string(buf));
621   EXPECT_EQ(2, SafeSPrintf(buf, "%02X", 1));
622   EXPECT_EQ("01", std::string(buf));
623   EXPECT_EQ(9, SafeSPrintf(buf, "%9X", -1));
624   EXPECT_EQ(" FFFFFFFF", std::string(buf));
625   EXPECT_EQ(9, SafeSPrintf(buf, "%09X", -1));
626   EXPECT_EQ("0FFFFFFFF", std::string(buf));
627   EXPECT_EQ(17, SafeSPrintf(buf, "%17X", -1LL));
628   EXPECT_EQ(" FFFFFFFFFFFFFFFF", std::string(buf));
629   EXPECT_EQ(17, SafeSPrintf(buf, "%017X", -1LL));
630   EXPECT_EQ("0FFFFFFFFFFFFFFFF", std::string(buf));
631   EXPECT_EQ(3, SafeSPrintf(buf, "%2X", 0x111));
632   EXPECT_EQ("111", std::string(buf));
633   EXPECT_EQ(4, SafeSPrintf(buf, "%-2X", 1));
634   EXPECT_EQ("%-2X", std::string(buf));
635   SafeSPrintf(fmt, "%%%dX", std::numeric_limits<ssize_t>::max()-1);
636   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
637             SafeSNPrintf(buf, 4, fmt, 1));
638   EXPECT_EQ("   ", std::string(buf));
639   SafeSPrintf(fmt, "%%0%dX", std::numeric_limits<ssize_t>::max()-1);
640   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
641             SafeSNPrintf(buf, 4, fmt, 1));
642   EXPECT_EQ("000", std::string(buf));
643   SafeSPrintf(fmt, "%%%dX",
644               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
645 #if defined(NDEBUG)
646   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
647   EXPECT_EQ("%X", std::string(buf));
648 #elif defined(ALLOW_DEATH_TEST)
649   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
650 #endif
651 
652   // Pointer %p
653   EXPECT_EQ(3, SafeSPrintf(buf, "%p", (void*)1));
654   EXPECT_EQ("0x1", std::string(buf));
655   EXPECT_EQ(4, SafeSPrintf(buf, "%4p", (void*)1));
656   EXPECT_EQ(" 0x1", std::string(buf));
657   EXPECT_EQ(4, SafeSPrintf(buf, "%04p", (void*)1));
658   EXPECT_EQ("0x01", std::string(buf));
659   EXPECT_EQ(5, SafeSPrintf(buf, "%4p", (void*)0x111));
660   EXPECT_EQ("0x111", std::string(buf));
661   EXPECT_EQ(4, SafeSPrintf(buf, "%-2p", (void*)1));
662   EXPECT_EQ("%-2p", std::string(buf));
663   SafeSPrintf(fmt, "%%%dp", std::numeric_limits<ssize_t>::max()-1);
664   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
665             SafeSNPrintf(buf, 4, fmt, (void*)1));
666   EXPECT_EQ("   ", std::string(buf));
667   SafeSPrintf(fmt, "%%0%dp", std::numeric_limits<ssize_t>::max()-1);
668   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
669             SafeSNPrintf(buf, 4, fmt, (void*)1));
670   EXPECT_EQ("0x0", std::string(buf));
671   SafeSPrintf(fmt, "%%%dp",
672               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
673 #if defined(NDEBUG)
674   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
675   EXPECT_EQ("%p", std::string(buf));
676 #elif defined(ALLOW_DEATH_TEST)
677   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
678 #endif
679 
680   // String
681   EXPECT_EQ(1, SafeSPrintf(buf, "%s", "A"));
682   EXPECT_EQ("A", std::string(buf));
683   EXPECT_EQ(2, SafeSPrintf(buf, "%2s", "A"));
684   EXPECT_EQ(" A", std::string(buf));
685   EXPECT_EQ(2, SafeSPrintf(buf, "%02s", "A"));
686   EXPECT_EQ(" A", std::string(buf));
687   EXPECT_EQ(3, SafeSPrintf(buf, "%2s", "AAA"));
688   EXPECT_EQ("AAA", std::string(buf));
689   EXPECT_EQ(4, SafeSPrintf(buf, "%-2s", "A"));
690   EXPECT_EQ("%-2s", std::string(buf));
691   SafeSPrintf(fmt, "%%%ds", std::numeric_limits<ssize_t>::max()-1);
692   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
693             SafeSNPrintf(buf, 4, fmt, "A"));
694   EXPECT_EQ("   ", std::string(buf));
695   SafeSPrintf(fmt, "%%0%ds", std::numeric_limits<ssize_t>::max()-1);
696   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
697             SafeSNPrintf(buf, 4, fmt, "A"));
698   EXPECT_EQ("   ", std::string(buf));
699   SafeSPrintf(fmt, "%%%ds",
700               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
701 #if defined(NDEBUG)
702   EXPECT_EQ(2, SafeSPrintf(buf, fmt, "A"));
703   EXPECT_EQ("%s", std::string(buf));
704 #elif defined(ALLOW_DEATH_TEST)
705   EXPECT_DEATH(SafeSPrintf(buf, fmt, "A"), "padding <= max_padding");
706 #endif
707 }
708 
TEST(SafeSPrintfTest,EmbeddedNul)709 TEST(SafeSPrintfTest, EmbeddedNul) {
710   char buf[] = { 'X', 'X', 'X', 'X' };
711   EXPECT_EQ(2, SafeSPrintf(buf, "%3c", 0));
712   EXPECT_EQ(' ', buf[0]);
713   EXPECT_EQ(' ', buf[1]);
714   EXPECT_EQ(0,   buf[2]);
715   EXPECT_EQ('X', buf[3]);
716 
717   // Check handling of a NUL format character. N.B. this takes two different
718   // code paths depending on whether we are actually passing arguments. If
719   // we don't have any arguments, we are running in the fast-path code, that
720   // looks (almost) like a strncpy().
721 #if defined(NDEBUG)
722   EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
723   EXPECT_EQ("%%", std::string(buf));
724   EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
725   EXPECT_EQ("%%", std::string(buf));
726 #elif defined(ALLOW_DEATH_TEST)
727   EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
728   EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
729 #endif
730 }
731 
TEST(SafeSPrintfTest,EmitNULL)732 TEST(SafeSPrintfTest, EmitNULL) {
733   char buf[40];
734 #if defined(__GNUC__)
735 #pragma GCC diagnostic push
736 #pragma GCC diagnostic ignored "-Wconversion-null"
737 #endif
738   EXPECT_EQ(1, SafeSPrintf(buf, "%d", NULL));
739   EXPECT_EQ("0", std::string(buf));
740   EXPECT_EQ(3, SafeSPrintf(buf, "%p", NULL));
741   EXPECT_EQ("0x0", std::string(buf));
742   EXPECT_EQ(6, SafeSPrintf(buf, "%s", NULL));
743   EXPECT_EQ("<NULL>", std::string(buf));
744 #if defined(__GCC__)
745 #pragma GCC diagnostic pop
746 #endif
747 }
748 
TEST(SafeSPrintfTest,PointerSize)749 TEST(SafeSPrintfTest, PointerSize) {
750   // The internal data representation is a 64bit value, independent of the
751   // native word size. We want to perform sign-extension for signed integers,
752   // but we want to avoid doing so for pointer types. This could be a
753   // problem on systems, where pointers are only 32bit. This tests verifies
754   // that there is no such problem.
755   char *str = reinterpret_cast<char *>(0x80000000u);
756   void *ptr = str;
757   char buf[40];
758   EXPECT_EQ(10, SafeSPrintf(buf, "%p", str));
759   EXPECT_EQ("0x80000000", std::string(buf));
760   EXPECT_EQ(10, SafeSPrintf(buf, "%p", ptr));
761   EXPECT_EQ("0x80000000", std::string(buf));
762 }
763 
764 }  // namespace strings
765 }  // namespace base
766