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<tt>It seems like a more elegant option would be if there was some
attribute of the engine that could be queried and override the
check against zero.<br>
<br>
-Ben<br>
</tt><br>
<div class="moz-cite-prefix">On 04/11/2017 06:20 PM, Michael Reilly
wrote:<br>
</div>
<blockquote
cite="mid:28f7c786-4a63-f723-467f-c416986e869c@cisco.com"
type="cite">
<pre wrap="">Unfortunately the check breaks code which doesn't know nor need to know the
keysize. The engine takes care of allocating buffers required.
Leaving it set to 0 has not broken anything yet. I supposed we could try to
somehow set it to an arbitrary non-zero value to please the == 0 check.
michael
On 04/11/2017 03:47 PM, Dr. Stephen Henson wrote:
</pre>
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<pre wrap="">On Tue, Apr 11, 2017, Michael Reilly wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi,
commit 222333cf01e2fec4a20c107ac9e820694611a4db added a check that the size
returned by EVP_PKEY_size(ctx->pkey) in M_check_autoarg() in
crypto/evp/pmeth_fn.c is != 0.
We are in the process of upgrading from 1.0.2j to 1.0.2k and discovered that the
if (pksize == 0) check added in 1.0.2k breaks some of our applications.
We use an engine for the RSA sign operation. The applications do not know
anything about the keypair being used. The keypair is kept private by the
engine so the application couldn't determine the attributes of the keypair if it
wanted to do so.
If this check is necessary is there a way to bypass it when the application does
not have the keypair but the engine being used is holding the keypair?
I know we can simply remove this line from our copy of the code but we like to
avoid modifying the openssl distributed code if at all possible.
</pre>
</blockquote>
<pre wrap="">
Well the point of that code is so an application knows how large a buffer to
allocate for the signature. If it returns zero I can't see how applications
can do that.
Note that you don't have to return the *precise* length of the signature just
an upper bound is sufficient.
Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: <a class="moz-txt-link-freetext" href="http://www.openssl.org">http://www.openssl.org</a>
</pre>
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<pre wrap="">
</pre>
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