In addition, I find that EVP_DigestInit_ex ends up bumping the reference count
*twice*...
In eng_table.c:
/* Try to initialise the ENGINE? */
if((ret->funct_ref > 0) || !(table_flags & ENGINE_TABLE_FLAG_NOINIT))
initres = engine_unlocked_init(ret);
else
initres = 0;
if(initres)
{
/* Update 'funct' */
if((fnd->funct != ret) && engine_unlocked_init(ret))
{
/* If there was a previous default we release it. */
if(fnd->funct)
engine_unlocked_finish(fnd->funct, 0);
To clarify the version, it's 1.0.1 built as FIPS-capable, but OpenSSL FIPS is
not enabled during this usage.
....................................
Erik Tkal
Juniper OAC/UAC/Pulse Development
Sent: Tuesday, March 27, 2012 10:45 AM
To: [email protected]
Subject: RE: ENGINE reference leak using EVP_Digest*
BTW, this is with OpenSSL 1.0.1; I did not try an older version.
Sent: Tuesday, March 27, 2012 10:20 AM
To: [email protected]<mailto:[email protected]>
Subject: ENGINE reference leak using EVP_Digest*
I have some code that uses the following sequence of calls (e.g.):
EVP_MD_CTX ctx;
EVP_MD_CTX_init(&ctx);
EVP_DigestInit_ex(&ctx, EVP_sha1(), NULL);
EVP_DigestUpdate(&ctx, pData, nSize);
EVP_DigestFinal_ex(&ctx, pOut, NULL);
EVP_DigestInit_ex(&ctx, EVP_sha1(), NULL);
EVP_DigestUpdate(&ctx, pData, nSize);
EVP_DigestFinal_ex(&ctx, pOut, NULL);
EVP_DigestInit_ex(&ctx, EVP_sha1(), NULL);
EVP_DigestUpdate(&ctx, pData, nSize);
EVP_DigestFinal_ex(&ctx, pOut, NULL);
EVP_MD_CTX_cleanup(&ctx);
The docs say that "After calling EVP_DigestFinal_ex() no additional calls to
EVP_DigestUpdate() can be made, but EVP_DigestInit_ex() can be called to
initialize a new digest operation."
In my case, there is an ENGINE registered to perform the SHA1 operations.
What happens, though is that EVP_DigestInit_ex() increments the ENGINE
reference, but EVP_DigestFinal_ex() does not decrement it. Only the
EVP_MD_CTX_cleanup() call is decrementing the reference count, and thus my
ENGINE never ends up being actually freed on the ENGINE_finish() call.
Is this a known issue? Do I really need to cleanup/reinit my CTX around each
hash sequence?
....................................
Erik Tkal
Juniper OAC/UAC/Pulse Development
