From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9427EEB64D9 for ; Mon, 26 Jun 2023 18:19:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231439AbjFZSTD (ORCPT ); Mon, 26 Jun 2023 14:19:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231452AbjFZSS6 (ORCPT ); Mon, 26 Jun 2023 14:18:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EF32E7F for ; Mon, 26 Jun 2023 11:18:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9754560F4B for ; Mon, 26 Jun 2023 18:18:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C186C433C8; Mon, 26 Jun 2023 18:18:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687803513; bh=q6xU1RZXwjZczp8czatjCzEI2Ra6intsSlDKa27wJCU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cHtKlHh/DGiUQpOKJk2i0vJHboZvWfM0e6STiF5BPA0BuWkbkXlMTcT634i9Cao2Z ZCPOA79AoEEk+6I3fLv2tA43aNx9u3txCn5b4qx9L8wmweLvV8AA5Rnn1048vHGW2h uRWneWPt13XqeXPSu6d9XBaH+QwKDY/zLkcQxX9U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Krister Johansen , Yonghong Song , Ilya Leoshkevich , Alexei Starovoitov Subject: [PATCH 6.3 086/199] bpf: ensure main program has an extable Date: Mon, 26 Jun 2023 20:09:52 +0200 Message-ID: <20230626180809.372516125@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230626180805.643662628@linuxfoundation.org> References: <20230626180805.643662628@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Krister Johansen commit 0108a4e9f3584a7a2c026d1601b0682ff7335d95 upstream. When subprograms are in use, the main program is not jit'd after the subprograms because jit_subprogs sets a value for prog->bpf_func upon success. Subsequent calls to the JIT are bypassed when this value is non-NULL. This leads to a situation where the main program and its func[0] counterpart are both in the bpf kallsyms tree, but only func[0] has an extable. Extables are only created during JIT. Now there are two nearly identical program ksym entries in the tree, but only one has an extable. Depending upon how the entries are placed, there's a chance that a fault will call search_extable on the aux with the NULL entry. Since jit_subprogs already copies state from func[0] to the main program, include the extable pointer in this state duplication. Additionally, ensure that the copy of the main program in func[0] is not added to the bpf_prog_kallsyms table. Instead, let the main program get added later in bpf_prog_load(). This ensures there is only a single copy of the main program in the kallsyms table, and that its tag matches the tag observed by tooling like bpftool. Cc: stable@vger.kernel.org Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs") Signed-off-by: Krister Johansen Acked-by: Yonghong Song Acked-by: Ilya Leoshkevich Tested-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/6de9b2f4b4724ef56efbb0339daaa66c8b68b1e7.1686616663.git.kjlx@templeofstupid.com Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -16198,9 +16198,10 @@ static int jit_subprogs(struct bpf_verif } /* finally lock prog and jit images for all functions and - * populate kallsysm + * populate kallsysm. Begin at the first subprogram, since + * bpf_prog_load will add the kallsyms for the main program. */ - for (i = 0; i < env->subprog_cnt; i++) { + for (i = 1; i < env->subprog_cnt; i++) { bpf_prog_lock_ro(func[i]); bpf_prog_kallsyms_add(func[i]); } @@ -16226,6 +16227,8 @@ static int jit_subprogs(struct bpf_verif prog->jited = 1; prog->bpf_func = func[0]->bpf_func; prog->jited_len = func[0]->jited_len; + prog->aux->extable = func[0]->aux->extable; + prog->aux->num_exentries = func[0]->aux->num_exentries; prog->aux->func = func; prog->aux->func_cnt = env->subprog_cnt; bpf_prog_jit_attempt_done(prog);