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<a href="https://gitlab.com/davidtr1037">David Trabish</a> created an issue <a href="https://gitlab.com/gnutls/libtasn1/-/issues/32">#32</a>:
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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">The bound check in ETYPE_OK may lead to out-of-bound access.</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">4.16.0</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">Ubuntu</p>
<h2 dir="auto">
<a id="user-content-how-reproducible" class="anchor" href="#how-reproducible" aria-hidden="true"></a>How reproducible:</h2>
<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">#include <stdlib.h></span>
<span id="LC2" class="line" lang="plaintext">#include <stdio.h></span>
<span id="LC3" class="line" lang="plaintext">#include <libtasn1.h></span>
<span id="LC4" class="line" lang="plaintext"></span>
<span id="LC5" class="line" lang="plaintext">int main(int argc, char *argv[]) {</span>
<span id="LC6" class="line" lang="plaintext"> unsigned int etype = 38;</span>
<span id="LC7" class="line" lang="plaintext"></span>
<span id="LC8" class="line" lang="plaintext"> unsigned int str_len = 10;</span>
<span id="LC9" class="line" lang="plaintext"> unsigned char *str = malloc(str_len);</span>
<span id="LC10" class="line" lang="plaintext"></span>
<span id="LC11" class="line" lang="plaintext"> unsigned int tl_len = 10;</span>
<span id="LC12" class="line" lang="plaintext"> unsigned char *tl = malloc(tl_len);</span>
<span id="LC13" class="line" lang="plaintext"></span>
<span id="LC14" class="line" lang="plaintext"> asn1_encode_simple_der(etype, str, str_len, tl, &tl_len);</span>
<span id="LC15" class="line" lang="plaintext"> </span>
<span id="LC16" class="line" lang="plaintext"> return 0;</span>
<span id="LC17" class="line" lang="plaintext">}</span></code></pre>
<p dir="auto">Steps to Reproduce:</p>
<ul dir="auto">
<li>Compile the program with <code>-fsanitize=address,leak,undefined</code>
</li>
<li>Run</li>
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<a id="user-content-actual-results" class="anchor" href="#actual-results" aria-hidden="true"></a>Actual results:</h2>
<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">==23616==ERROR: AddressSanitizer: global-buffer-overflow on address 0x00000042e208 at pc 0x000000402854 bp 0x7fffe0995170 sp 0x7fffe0995160</span>
<span id="LC2" class="line" lang="plaintext">READ of size 8 at 0x00000042e208 thread T0</span>
<span id="LC3" class="line" lang="plaintext"> #0 0x402853 in asn1_encode_simple_der ../../libtasn1-4.16.0/lib/coding.c:218</span></code></pre>
<h2 dir="auto">
<a id="user-content-expected-results" class="anchor" href="#expected-results" aria-hidden="true"></a>Expected results:</h2>
<p dir="auto">The macro should do this check instead:</p>
<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">(etype) < _asn1_tags_size</span></code></pre>
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