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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - strstreambuf::overflow passes wrong value to setp"
href="https://llvm.org/bugs/show_bug.cgi?id=27915">27915</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>strstreambuf::overflow passes wrong value to setp
</td>
</tr>
<tr>
<th>Product</th>
<td>libc++
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ahatanak@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>strstreambuf::overflow allocates a new memory block when the current character
pointer reaches the end pointer (when pptr() == epptr()) and then repositions
the pointers that define the put area calling setp.
setp(buf + einp, buf + einp + eout);
This code is incorrect since the third argument should be a value of a pointer
that points to the end of the put area. This bug causes ASAN to report an error
when the following program is compiled and run:
$ cat test.c
#include <iostream>
#include <string>
#include <strstream>
int main(int, char const **argv) {
std::ostrstream oss;
std::string s;
for (int i = 0; i < 4096; ++i)
s.push_back((i % 16) + 'a');
oss << s << std::ends;
std::cout << oss.str();
oss.freeze(false);
return 0;
}
A patch to fix this bug has been submitted here:
<a href="http://reviews.llvm.org/D20334">http://reviews.llvm.org/D20334</a></pre>
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