Fix memory leak when rejecting bogus DH parameters.

While back-patching e0e569e1d, I noted that there were some other
places where we ought to be applying DH_free(); namely, where we
load some DH parameters from a file and then reject them as not
being sufficiently secure.  While it seems really unlikely that
anybody would hit these code paths in production, let alone do
so repeatedly, let's fix it for consistency.

Back-patch to v10 where this code was introduced.

Discussion: https://postgr.es/m/16160-18367e56e9a28264@postgresql.org

diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index a37b5e47c2eb6b7b702da53b6f7f60595de251f9..f88779c6d281f5f8691a28fc89f227057efb0c10 100644 (file)
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -899,6 +899,7 @@ load_dh_file(char *filename, bool isServerStart)
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid DH parameters: %s",
                        SSLerrmessage(ERR_get_error()))));
+       DH_free(dh);
        return NULL;
    }
    if (codes & DH_CHECK_P_NOT_PRIME)
@@ -906,6 +907,7 @@ load_dh_file(char *filename, bool isServerStart)
        ereport(isServerStart ? FATAL : LOG,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid DH parameters: p is not prime")));
+       DH_free(dh);
        return NULL;
    }
    if ((codes & DH_NOT_SUITABLE_GENERATOR) &&
@@ -914,6 +916,7 @@ load_dh_file(char *filename, bool isServerStart)
        ereport(isServerStart ? FATAL : LOG,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid DH parameters: neither suitable generator or safe prime")));
+       DH_free(dh);
        return NULL;
    }