Incorrect using rw_asnprintf() with %{+} format and not NUL-terminated buffer
in _rw_fmtflags(), _rw_fmtevent(), _rw_fmtlc()
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Key: STDCXX-765
URL: https://issues.apache.org/jira/browse/STDCXX-765
Project: C++ Standard Library
Issue Type: Bug
Components: Test Driver
Affects Versions: 4.2.0
Environment: All
Reporter: Farid Zaripov
Fix For: 4.2.1
The buf parameter of the _rw_fmtflags(), _rw_fmtevent() and _rw_fmtlc()
functions contains not NUL-terminated data. The length of data in buf is stored
in buf.endoff.
The rw_asnprintf() function accepts the only buf.pbuf and buf.pbufsize, but not
buf.endoff. When %{+} format is used, the length of data in buf calculated
using strlen() function, but this length is incorrect due to data is not
NUL-terminated.
Another bug is that _rw_fmtflags(), _rw_fmtevent() and _rw_fmtlc() functions
are returns len, but without updating the buf.endoff. Due to this the result of
rw_asnprintf() is cutted in further processing.
These problems are detected in 0.printf test after lates update.
The schematic patch without error checking is below. This patch is not intended
to apply. Its only shows how these bugs should be fixed.
{noformat}
Index: tests/src/fmt_bits.cpp
===================================================================
--- tests/src/fmt_bits.cpp (revision 637399)
+++ tests/src/fmt_bits.cpp (working copy)
@@ -204,9 +204,12 @@
#endif // _RWSTD_NO_EXT_BIN_IO
- len = rw_asnprintf (buf.pbuf, buf.pbufsize,
- "%{+} | %{?}std::ios::%{;}base(%d)",
- spec.fl_pound, base);
+ (*buf.pbuf) [buf.endoff] = '\0';
+ int res = rw_asnprintf (buf.pbuf, buf.pbufsize,
+ "%{+} | %{?}std::ios::%{;}base(%d)",
+ spec.fl_pound, base);
+ buf.endoff += res;
+ len += res;
}
return len;
@@ -303,9 +306,12 @@
: std::ios::erase_event == event ? "erase_event"
: 0;
- return rw_asnprintf (buf.pbuf, buf.pbufsize,
- "%{+}%{?}std::ios::%{;}%{?}%s%{:}event(%d)%{;}",
- spec.fl_pound, 0 != str, str, event);
+ (*buf.pbuf) [buf.endoff] = '\0';
+ int len = rw_asnprintf (buf.pbuf, buf.pbufsize,
+ "%{+}%{?}std::ios::%{;}%{?}%s%{:}event(%d)%{;}",
+ spec.fl_pound, 0 != str, str, event);
+ buf.endoff += len;
+ return len;
}
/********************************************************************/
@@ -329,8 +335,12 @@
}
- if (str)
- return rw_asnprintf (buf.pbuf, buf.pbufsize, "%{+}%s", str);
+ if (str) {
+ (*buf.pbuf) [buf.endoff] = '\0';
+ int len = rw_asnprintf (buf.pbuf, buf.pbufsize, "%{+}%s", str);
+ buf.endoff += len;
+ return len;
+ }
static const Bitnames names [] = {
BITNAME (std::locale, all),
{noformat}
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