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<h2 dir="auto">
<a id="user-content-description-of-problem" class="anchor" href="#description-of-problem" aria-hidden="true"></a>Description of problem:</h2>
<p dir="auto">Found a bug in the parser for Gnu libtasn1-4.9, they in the case of making the tokens and by that adding a "-" to the string go over the length of their buffer. So the problem is using a sizeof on the buffer size and making the buffer too short. Looks like two problems, this way the problem creeps as you grow the buffer to add room for the "-":</p>
<h2 dir="auto">
<a id="user-content-version-of-libtasn1-used" class="anchor" href="#version-of-libtasn1-used" aria-hidden="true"></a>Version of libtasn1 used:</h2>
<p dir="auto">Gnu 1-4.9</p>
<h2 dir="auto">
<a id="user-content-distributor-of-libtasn1-eg-ubuntu-fedora-rhel" class="anchor" href="#distributor-of-libtasn1-eg-ubuntu-fedora-rhel" aria-hidden="true"></a>Distributor of libtasn1 (e.g., Ubuntu, Fedora, RHEL)</h2>
<p dir="auto">Gnu source tarball.</p>
<h2 dir="auto">
<a id="user-content-how-reproducible" class="anchor" href="#how-reproducible" aria-hidden="true"></a>How reproducible:</h2>
<p dir="auto">Compile using Gcc 8 using -Werror=format-truncation</p>
<p dir="auto">Steps to Reproduce:</p>
<ul dir="auto">
<li>one</li>
</ul>
<p dir="auto">Unpack tarball and run configure, please see attached config.status.</p>
<ul dir="auto">
<li>two</li>
</ul>
<p dir="auto">Make using those flags.</p>
<ul dir="auto">
<li>three</li>
</ul>
<p dir="auto">See Gcc flag the error as follows:</p>
<h2 dir="auto">
<a id="user-content-actual-results" class="anchor" href="#actual-results" aria-hidden="true"></a>Actual results:</h2>
<p dir="auto">GNU C17 (GCC) version 8.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 81f798d4ff0871f00b0a4f3f1296b20a
ASN1.c: In function '_asn1_yyparse':
ASN1.y:164:47: error: 'snprintf' output may be truncated before the last format character [-Werror=format-truncation=]
| '-' NUM {snprintf($$,sizeof($$),"-%s",$2);}
^~~~~
ASN1.y:164:6: note: 'snprintf' output between 2 and 66 bytes into a destination of size 65
| '-' NUM {snprintf($$,sizeof($$),"-%s",$2);}
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ASN1.y:152:47: error: 'snprintf' output may be truncated before the last format character [-Werror=format-truncation=]
neg_num : '-' NUM {snprintf($$,sizeof($$),"-%s",$2);}
^~~~~
ASN1.y:152:6: note: 'snprintf' output between 2 and 66 bytes into a destination of size 65
neg_num : '-' NUM {snprintf($$,sizeof($$),"-%s",$2);}
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>
cc1: all warnings being treated as errors
Makefile:1112: recipe for target 'ASN1.lo' failed</p>
<p dir="auto">Please see:</p>
<p dir="auto"><a href="https://gitlab.com/gnutls/libtasn1/uploads/7cc9158451b4dbe2846fb9ebb6416fe7/config.status">config.status</a></p>
<p dir="auto"><a href="https://gitlab.com/gnutls/libtasn1/uploads/5999709704b2c0635b697fd893c77e0e/gcc_v.txt">gcc_v.txt</a></p>
<h2 dir="auto">
<a id="user-content-expected-results" class="anchor" href="#expected-results" aria-hidden="true"></a>Expected results:</h2>
<p dir="auto">No warning or errors.</p>
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