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 53564C433F5 for ; Fri, 15 Apr 2022 12:01:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352852AbiDOMD1 (ORCPT ); Fri, 15 Apr 2022 08:03:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353094AbiDOMDP (ORCPT ); Fri, 15 Apr 2022 08:03:15 -0400 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D5928CD80 for ; Fri, 15 Apr 2022 05:00:26 -0700 (PDT) Received: by mail-ed1-x52a.google.com with SMTP id z99so9701002ede.5 for ; Fri, 15 Apr 2022 05:00:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=VYOzeG29CXQZt+EUoBxDz5C2HqXrmoOTzgQchubVUnw=; b=KZ1WXwhUoVJ1zKh6jOVB6NKwa3rVSOVll0LX11G4LMJqZLgrOxdc0Nido2wf0KVrUL QbQZKb0zUh4GA4wvEjtxfg3xoDC6KfjI+4tPj5cY6S7O/RDOfoORt7ug0e8KBYIKR6F1 wqsK2jvTdM10VMSKLArdMdrDIGuqSTMK2Vfp0ha7XSdzDlsAo4NcDaebpfgbeRsFqp2q 23ZoGiV4d88hD1mjxTITOwv4KYkZwQG5DcdIWbeNpnplVuWRsg2jNkshVCjtGo55sdMj bGZ9n2yhZ+PZnwQ5hRQBXkaUaoPWuL/RfDB670nLElFI50nivFFG3SavzzLIEQsgcOI4 SQGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=VYOzeG29CXQZt+EUoBxDz5C2HqXrmoOTzgQchubVUnw=; b=XrKroXJanGmmXZR3SIzCtLLUYJLPnvSGtSOcrgNSSA6jRE2ivGxtLdJnktNlDaBkY3 0BTlMKDBu/OzWrZA+aYGNL8f3az97yY8kxjV1oGWF3OkNdPlJZtTN4tL9aE/ci9sYFM3 ciMWauymQ+h6Tim+Lpx2IvqCiY6a3rodvUZewzmrrG216ADfpJlFSrqD/wFwsYIWI6Gv g3WcTLdRDjWbu4zYymJeK6PdGVCQaAss/NagYYWPkp1DKh1NnXnynePBsni4Fu7YhRx5 CrzXTowtbEKpqmYgVwQSFrboB2ZyGGI47lxG55UCxezdLuK4lZ/PnpqJYQMpKMMYSciM 63nQ== X-Gm-Message-State: AOAM5317DZbrAqx+ywoIHDjVMcSfTC03a93FCkKolihnZ0MIZzVGZnf+ ucjUpshQcCc5DpLGuoBhTwLd4V1QDMeWFQ== X-Google-Smtp-Source: ABdhPJwkTo4cD5aGUjTPLaU3oHB2nbvGjo+BUYM2n4Cpb96cwuWM+dWa1P41qWbDtEA92qUfOrfN9g== X-Received: by 2002:aa7:da8d:0:b0:41d:71be:d8bd with SMTP id q13-20020aa7da8d000000b0041d71bed8bdmr7888461eds.71.1650024024869; Fri, 15 Apr 2022 05:00:24 -0700 (PDT) Received: from zero.. (host-79-54-81-151.retail.telecomitalia.it. [79.54.81.151]) by smtp.gmail.com with ESMTPSA id dn7-20020a17090794c700b006e8b176143bsm1621164ejc.155.2022.04.15.05.00.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Apr 2022 05:00:24 -0700 (PDT) From: Alessandro Astone To: tkjos@android.com, gregkh@linuxfoundation.org, brauner@kernel.org, arve@android.com, linux-kernel@vger.kernel.org, maco@android.com Cc: Alessandro Astone , Joel Fernandes , Hridya Valsaraju , Suren Baghdasaryan Subject: [PATCH v2 2/2] binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0 Date: Fri, 15 Apr 2022 14:00:14 +0200 Message-Id: <20220415120015.52684-1-ales.astone@gmail.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some android userspace is sending BINDER_TYPE_FDA objects with num_fds=0. Like the previous patch, this is reproducible when playing a video. Before commit 09184ae9b575 BINDER_TYPE_FDA objects with num_fds=0 were 'correctly handled', as in no fixup was performed. After commit 09184ae9b575 we aggregate fixup and skip regions in binder_ptr_fixup structs and distinguish between the two by using the skip_size field: if it's 0, then it's a fixup, otherwise skip. When processing BINDER_TYPE_FDA objects with num_fds=0 we add a skip region of skip_size=0, and this causes issues because now binder_do_deferred_txn_copies will think this was a fixup region. To address that, return early from binder_translate_fd_array to avoid adding an empty skip region. Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data") Signed-off-by: Alessandro Astone --- drivers/android/binder.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 31176edb1069..f3b639e89dd8 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2491,6 +2491,9 @@ static int binder_translate_fd_array(struct list_head *pf_head, struct binder_proc *proc = thread->proc; int ret; + if (fda->num_fds == 0) + return 0; + fd_buf_size = sizeof(u32) * fda->num_fds; if (fda->num_fds >= SIZE_MAX / sizeof(u32)) { binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n", -- 2.35.1