Fix potential index-out-of-bounds and malformed strings

Size of the buffer was smaller then max size used in strftime
and alike function calls.

Moreover, according to man strftime contents of the buffer
is undefined in case in which actual string is longer than the
specified max size, therefore buffer is zeroed and last byte
left unused.
Signed-off-by: NRobert Drab <robert.drab@huawei.com>

kernel_lite/time_posix/src/TimeUtilsTest.cpp

@@ -246,25 +246,25 @@ HWTEST_F(TimeUtilsTest, testMktime, Function | MediumTest | Level2)
 */
 HWTEST_F(TimeUtilsTest, testStrftime, Function | MediumTest | Level3)
 {
-    char buffer[32];
+    char buffer[80] = {0};
     time_t mtime = 18880;
-    size_t ftime = strftime(buffer, 80, "%Ex %EX %A", localtime(&mtime));
+    size_t ftime = strftime(buffer, sizeof(buffer) - 1, "%Ex %EX %A", localtime(&mtime));
     EXPECT_GT(ftime, g_zero) << "strftime return error!";
     EXPECT_STREQ(buffer, "01/01/70 05:14:40 Thursday") << "buffer return error!";
 
     mtime = LONG_MAX;
-    ftime = strftime(buffer, 80, "%y-%m-%d %H:%M:%S", localtime(&mtime));
+    ftime = strftime(buffer, sizeof(buffer) - 1, "%y-%m-%d %H:%M:%S", localtime(&mtime));
     EXPECT_STREQ(buffer, "38-01-19 03:14:07") << "buffer return error!";
 
     mtime = 253402300799;
-    ftime = strftime(buffer, 80, "%Y-%m-%d %H:%M:%S", localtime(&mtime));
+    ftime = strftime(buffer, sizeof(buffer) - 1, "%Y-%m-%d %H:%M:%S", localtime(&mtime));
     EXPECT_STREQ(buffer, "9999-12-31 23:59:59") << "buffer return error!";
 
     mtime = LONG_MIN;
-    ftime = strftime(buffer, 80, "%x %X", localtime(&mtime));
+    ftime = strftime(buffer, sizeof(buffer) - 1, "%x %X", localtime(&mtime));
     EXPECT_STREQ(buffer, "12/13/01 20:45:52") << "buffer return error!";
 
-    ftime = strftime(buffer, 11, "%Y-%m-%d %H:%M:%S", localtime(&mtime));
+    ftime = strftime(buffer, sizeof(buffer) - 1, "%Y-%m-%d %H:%M:%S", localtime(&mtime));
     EXPECT_EQ(ftime, g_zero) << "strftime return error!";
     EXPECT_STREQ(buffer, "1901-12-13") << "buffer return error!";
 }
@@ -277,10 +277,10 @@ HWTEST_F(TimeUtilsTest, testStrftime, Function | MediumTest | Level3)
 HWTEST_F(TimeUtilsTest, testStrftimeL, Function | MediumTest | Level2)
 {
     struct tm *tm1;
-    char buffer[32];
+    char buffer[80] = {0};
 
     tm1 = localtime(&g_time);
-    size_t ftime = strftime_l(buffer, 80, "%F %T %Z", tm1, (locale_t)0);
+    size_t ftime = strftime_l(buffer, sizeof(buffer) - 1, "%F %T %Z", tm1, (locale_t)0);
     EXPECT_GT(ftime, g_zero) << "strftime return error!";
     EXPECT_STREQ(buffer, "1970-01-01 05:14:40 UTC") << "buffer return error!";
 }
@@ -292,13 +292,13 @@ HWTEST_F(TimeUtilsTest, testStrftimeL, Function | MediumTest | Level2)
 */
 HWTEST_F(TimeUtilsTest, testWcsftime, Function | MediumTest | Level2)
 {
-    wchar_t buff[48];
-    size_t len = wcsftime(buff, sizeof(buff), L"%A %c", localtime(&g_time));
+    wchar_t buff[48] = {0};
+    size_t len = wcsftime(buff, sizeof(buff) - 1, L"%A %c", localtime(&g_time));
     LOG("buff = %ls, len = %ld\n", buff, (long)len);
     EXPECT_EQ(len, (size_t)33) << "wcsftime return error!";
     EXPECT_STREQ(buff, L"Thursday Thu Jan  1 05:14:40 1970") << "buff return error!";
 
-    len = wcsftime(buff, 9, L"%A %c", localtime(&g_time));
+    len = wcsftime(buff, sizeof(buff) - 1, L"%A %c", localtime(&g_time));
     LOG("buff = %ls, len = %ld\n", buff, (long)len);
     EXPECT_EQ(len, g_zero) << "wcsftime return error!";
     EXPECT_STREQ(buff, L"Thursday") << "buff return error!";