Re: [syzbot] [crypto?] general protection fault in cryptd_hash_export

[David Howells]

Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:

> David, the logic for calling hash_alloc_result looks quite different
> from that on whether you do the hash finalisation.  I'd suggest that
> you change them to use the same check, and also set use NULL instead
> of ctx->result if you didn't call hash_alloc_result.

I don't fully understand what the upstream hash_sendmsg() is doing.  Take this
bit for example:

	if (!ctx->more) {
		if ((msg->msg_flags & MSG_MORE))
			hash_free_result(sk, ctx);

Why is it freeing the old result only if MSG_MORE is now set, but wasn't set
on the last sendmsg()?

David