From nobody Fri Dec 19 06:16:24 2025 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 8B28EC433FE for ; Sat, 22 Oct 2022 07:51:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231935AbiJVHvm (ORCPT ); Sat, 22 Oct 2022 03:51:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231800AbiJVHtK (ORCPT ); Sat, 22 Oct 2022 03:49:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B869263B6E; Sat, 22 Oct 2022 00:46:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 076A1B82E0A; Sat, 22 Oct 2022 07:43:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C927C433D6; Sat, 22 Oct 2022 07:43:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666424635; bh=tT3anD75WlhdKhqutw+l0nDcDEE3SDZgAaFmH8y3fag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P1YRs7C1/pXV7rzP35otxYKrd7Yh2GKOz8rhFyJ3ikJwKzfYtkZQLUdRQymRqLYRG j0utn4lc2ziQdiVJGJV0/MSROQPKuhfunQkfgh1FDjqnmONctTMjkSYgcM7qrrEO4J lefCFDMKIqofZSrW24cpMjI0c8CuD8oKvP8gM5NA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hao Sun , Hou Tao , Martin KaFai Lau , Sasha Levin Subject: [PATCH 5.19 219/717] bpf: Propagate error from htab_lock_bucket() to userspace Date: Sat, 22 Oct 2022 09:21:38 +0200 Message-Id: <20221022072453.934425338@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221022072415.034382448@linuxfoundation.org> References: <20221022072415.034382448@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Hou Tao [ Upstream commit 66a7a92e4d0d091e79148a4c6ec15d1da65f4280 ] In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns -EBUSY, it will go to next bucket. Going to next bucket may not only skip the elements in current bucket silently, but also incur out-of-bound memory access or expose kernel memory to userspace if current bucket_cnt is greater than bucket_size or zero. Fixing it by stopping batch operation and returning -EBUSY when htab_lock_bucket() fails, and the application can retry or skip the busy batch as needed. Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked") Reported-by: Hao Sun Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20220831042629.130006-3-houtao@huaweicloud.= com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- kernel/bpf/hashtab.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 717f85973443..e20f3d0e3fc7 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1704,8 +1704,11 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *m= ap, /* do not grab the lock unless need it (bucket_cnt > 0). */ if (locked) { ret =3D htab_lock_bucket(htab, b, batch, &flags); - if (ret) - goto next_batch; + if (ret) { + rcu_read_unlock(); + bpf_enable_instrumentation(); + goto after_loop; + } } =20 bucket_cnt =3D 0; --=20 2.35.1