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From: Michael Paquier <michael@paquier.xyz>
To: Postgres hackers <pgsql-hackers@lists.postgresql.org>
Subject: Possible memory leak in pgcrypto with EVP_MD_CTX
Date: Thu, 15 Oct 2020 16:22:12 +0900
Message-ID: <20201015072212.GC2305@paquier.xyz> (raw)

Hi all,

It happens that pgcrypto has the following leak if a digest cannot be
initialized:

inline patch 1: contrib/pgcrypto/openssl.c (+1/-0 lines) download inline-1.patch--- a/contrib/pgcrypto/openssl.c
+++ b/contrib/pgcrypto/openssl.c
@@ -202,6 +202,7 @@ px_find_digest(const char *name, PX_MD **res)
    }
    if (EVP_DigestInit_ex(ctx, md, NULL) == 0)
    {
+       EVP_MD_CTX_destroy(ctx);
        pfree(digest);
        return -1;
    }


That's a bit annoying, because this memory is allocated directly by
OpenSSL, and Postgres does not know how to free it until it gets
registered in the list of open_digests that would be used by the
cleanup callback, so I think that we had better back-patch this fix.

Thoughts?
--
Michael

Patches and attachments: download all (3 files, .tar.gz)


pgcrypto-leak.patch (text/x-diff, 353B) download
diff --git a/contrib/pgcrypto/openssl.c b/contrib/pgcrypto/openssl.c
index 90951a8ae7..ed96e4ce53 100644
--- a/contrib/pgcrypto/openssl.c
+++ b/contrib/pgcrypto/openssl.c
@@ -202,6 +202,7 @@ px_find_digest(const char *name, PX_MD **res)
 	}
 	if (EVP_DigestInit_ex(ctx, md, NULL) == 0)
 	{
+		EVP_MD_CTX_destroy(ctx);
 		pfree(digest);
 		return -1;
 	}


  signature.asc (application/pgp-signature, 832B) download

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  Subject: Re: Possible memory leak in pgcrypto with EVP_MD_CTX
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