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 282A9ECAAD8 for ; Fri, 23 Sep 2022 15:24:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229507AbiIWPY5 (ORCPT ); Fri, 23 Sep 2022 11:24:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231392AbiIWPYz (ORCPT ); Fri, 23 Sep 2022 11:24:55 -0400 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E850C760FA for ; Fri, 23 Sep 2022 08:24:54 -0700 (PDT) Received: by mail-wm1-x330.google.com with SMTP id l8so461542wmi.2 for ; Fri, 23 Sep 2022 08:24:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date; bh=t6FGNWMCdKGOCPkqauCnhALpSopCNLftgjMxt06NOzM=; b=MhJd051Uy/+PQpeZssQaFQxthBsDW/9Cu4o43OWMnWB8TfD0IFNM/m+BRb2u5LNSUr WmX2zsGvndTNdwvYFjL0gNRKpoKQXQorBGlIr3gLYcK+jYcl81Lv+f0MrbWXwnvVk08Y 4CjsBS4arklqNc0YCbvQD0hC3iSAsFRN7KW6wcCEfEVBbyI9dD0O2CvMhX/s/Eq+nu6T +bxJ5SmaB8Xb8MCRmGnk1fzihlB82qllciF0mJ0Oh5cdnDkPvGbE+fdTqz27mWYZaTNN go1cSFmWBCBOj9UmwaNeV6Uzo7hYTd3qboy+EqycPe+XlyQNzCgclOQuZaG96NE6E9iY jCWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date; bh=t6FGNWMCdKGOCPkqauCnhALpSopCNLftgjMxt06NOzM=; b=N/dYWFbya25UnzYfFbuWdVejimZ1609W3yp2hy5lXMwxg9mA7m512+hrdSFqhCAbpP JCKlHLqMhOAthDonqgbh5H/HkLWzzXrolEIiVN61eHXLC+ExEvLjOS1+Uh6GWv53FrLp bwdlcqjO2W1SkshtG5W8bN9Yl5itiKnuGziPkHfCkRLeQ6kZcVviOd+nUhBr+QrzVSzW hQmbP0VMcQNtniOT1ikhSRUxrWDYWZbKDViL0lAYGtKpSy/JJD5HaM4vkIybTCDf+/8f mwYJAQLEPqnEu0NaJ9YM/Tn0M1UdKaVDq+rOYvRy9sgf3PlWJQy1jixjtzRjRUubtwNh c5AA== X-Gm-Message-State: ACrzQf21Q45fAFuBGafH+njBCQX7z8NTwyUSqE1oN6Y0WXt34ZrMBXVB DtP7XSweGIj5eFKGXp/qlzu/n2J2A1g= X-Google-Smtp-Source: AMsMyM7ZEn0DRGILVaTwHOAWwIkzWE7eoh2NZZn/RoMhdp03+Y4SFqllSOnETUxP9Clzbn71hbbUdg== X-Received: by 2002:a7b:ce0d:0:b0:3b4:8728:3e7e with SMTP id m13-20020a7bce0d000000b003b487283e7emr6042885wmc.182.1663946693210; Fri, 23 Sep 2022 08:24:53 -0700 (PDT) Received: from 127.0.0.1localhost (188.28.201.74.threembb.co.uk. [188.28.201.74]) by smtp.gmail.com with ESMTPSA id t11-20020a05600c41cb00b003b31fc77407sm2631684wmh.30.2022.09.23.08.24.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Sep 2022 08:24:52 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com, Dylan Yudaken , syzbot+4c597a574a3f5a251bda@syzkaller.appspotmail.com Subject: [PATCH for-next v2] io_uring/net: fix UAF in io_sendrecv_fail() Date: Fri, 23 Sep 2022 16:23:34 +0100 Message-Id: <23ab8346e407ea50b1198a172c8a97e1cf22915b.1663945875.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org We should not assume anything about ->free_iov just from REQ_F_ASYNC_DATA but rather rely on REQ_F_NEED_CLEANUP, as we may allocate ->async_data but failed init would leave the field in not consistent state. The easiest solution is to remove removing REQ_F_NEED_CLEANUP and so ->async_data dealloc from io_sendrecv_fail() and let io_send_zc_cleanup() do the job. The catch here is that we also need to prevent double notif flushing, just test it for NULL and zero where it's needed. BUG: KASAN: use-after-free in io_sendrecv_fail+0x3b0/0x3e0 io_uring/net.c:1221 Write of size 8 at addr ffff8880771b4080 by task syz-executor.3/30199 CPU: 1 PID: 30199 Comm: syz-executor.3 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15e/0x45d mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 io_sendrecv_fail+0x3b0/0x3e0 io_uring/net.c:1221 io_req_complete_failed+0x155/0x1b0 io_uring/io_uring.c:873 io_drain_req io_uring/io_uring.c:1648 [inline] io_queue_sqe_fallback.cold+0x29f/0x788 io_uring/io_uring.c:1931 io_submit_sqe io_uring/io_uring.c:2160 [inline] io_submit_sqes+0x1180/0x1df0 io_uring/io_uring.c:2276 __do_sys_io_uring_enter+0xac6/0x2410 io_uring/io_uring.c:3216 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: c4c0009e0b56e ("io_uring/net: combine fail handlers") Reported-by: syzbot+4c597a574a3f5a251bda@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov --- v2: remove unused variable io_uring/net.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/io_uring/net.c b/io_uring/net.c index 757a300578f4..2af56661590a 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -915,9 +915,11 @@ void io_send_zc_cleanup(struct io_kiocb *req) io = req->async_data; kfree(io->free_iov); } - zc->notif->flags |= REQ_F_CQE_SKIP; - io_notif_flush(zc->notif); - zc->notif = NULL; + if (zc->notif) { + zc->notif->flags |= REQ_F_CQE_SKIP; + io_notif_flush(zc->notif); + zc->notif = NULL; + } } int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) @@ -1202,7 +1204,6 @@ int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags) void io_sendrecv_fail(struct io_kiocb *req) { struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg); - struct io_async_msghdr *io; int res = req->cqe.res; if (req->flags & REQ_F_PARTIAL_IO) @@ -1215,12 +1216,6 @@ void io_sendrecv_fail(struct io_kiocb *req) io_notif_flush(sr->notif); sr->notif = NULL; } - if (req_has_async_data(req)) { - io = req->async_data; - kfree(io->free_iov); - io->free_iov = NULL; - } - req->flags &= ~REQ_F_NEED_CLEANUP; io_req_set_res(req, res, req->cqe.flags); } -- 2.37.2