By modeling the issue fixed by commit 0e8b6c9 with codeql I was able to find some variants of the pattern .

Bug 1:

If mods = OPENSSL_zalloc(sizeof(*mods) * NUMPRIMES); fails to allocate memory it will execute a goto that will perform BN_CTX_end(ctx); on the context without a matching BN_CTX_start.

Bug 2:

If ret = BN_new(); fails to allocate memory it will execute a goto that will perform BN_CTX_end(ctx); on the context without a matching BN_CTX_start.

This can happen twice in the function so both cases would need to be addressed.

Bug 3:

If BN_priv_rand_ex(Xp, nbits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY, ctx)) fails it will execute a goto that will perform BN_CTX_end(ctx); on the context without a matching BN_CTX_start.

Bug 4:

If generator = EC_GROUP_get0_generator(group); is null, it will execute a goto that will perform BN_CTX_end(ctx); on the context without a matching BN_CTX_start.

I've already fixed the issues and am creating the issue to refer to it in the PR.