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 X-Spam-Level: X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08319C4741F for ; Fri, 25 Sep 2020 12:51:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C072421741 for ; Fri, 25 Sep 2020 12:51:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601038272; bh=bMf/2kq171M4B1i5Xq3TAvyNu8NheJPX7nNjgOlOZso=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aoDdAQEtAYczp19Z6AkWHoEhYorTCEVDG6caDcOr5AlvItHQAH6FZRrV5VC1lyHZI 8qeDv/L/IDl3JKv0c/BOGZqY4IDxDg8NykW0Ryc0mGdl1cOgqP5j5C5hEvN3pSoRfw i1rkl9ArkLvASKXfIFVP3dN0OJydI8NbZJySOXsg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729169AbgIYMvK (ORCPT ); Fri, 25 Sep 2020 08:51:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:55162 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729142AbgIYMvF (ORCPT ); Fri, 25 Sep 2020 08:51:05 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 639672075E; Fri, 25 Sep 2020 12:51:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601038264; bh=bMf/2kq171M4B1i5Xq3TAvyNu8NheJPX7nNjgOlOZso=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d8+E0frTZAs+p0wUnw5ADJ7nVOYW4Wt9mwclHJILDN8jcnQfYAMV0cUxIw9DF/e/C CRYCbi3lgwv9V3oTBI5v/TpsN2ppRu1NQcMS9HHVeaRep4M9MjA2PdTQOVchzCV6/o gVwQg7IVZ6Dsjl4LvodA2s+H7ikl2CtzmaiPTooc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , Carl Huang , Wen Gong , Bjorn Andersson , Manivannan Sadhasivam , "David S. Miller" Subject: [PATCH 5.8 41/56] net: qrtr: check skb_put_padto() return value Date: Fri, 25 Sep 2020 14:48:31 +0200 Message-Id: <20200925124734.027324810@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200925124727.878494124@linuxfoundation.org> References: <20200925124727.878494124@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit 3ca1a42a52ca4b4f02061683851692ad65fefac8 ] If skb_put_padto() returns an error, skb has been freed. Better not touch it anymore, as reported by syzbot [1] Note to qrtr maintainers : this suggests qrtr_sendmsg() should adjust sock_alloc_send_skb() second parameter to account for the potential added alignment to avoid reallocation. [1] BUG: KASAN: use-after-free in __skb_insert include/linux/skbuff.h:1907 [inline] BUG: KASAN: use-after-free in __skb_queue_before include/linux/skbuff.h:2016 [inline] BUG: KASAN: use-after-free in __skb_queue_tail include/linux/skbuff.h:2049 [inline] BUG: KASAN: use-after-free in skb_queue_tail+0x6b/0x120 net/core/skbuff.c:3146 Write of size 8 at addr ffff88804d8ab3c0 by task syz-executor.4/4316 CPU: 1 PID: 4316 Comm: syz-executor.4 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 __skb_insert include/linux/skbuff.h:1907 [inline] __skb_queue_before include/linux/skbuff.h:2016 [inline] __skb_queue_tail include/linux/skbuff.h:2049 [inline] skb_queue_tail+0x6b/0x120 net/core/skbuff.c:3146 qrtr_tun_send+0x1a/0x40 net/qrtr/tun.c:23 qrtr_node_enqueue+0x44f/0xc00 net/qrtr/qrtr.c:364 qrtr_bcast_enqueue+0xbe/0x140 net/qrtr/qrtr.c:861 qrtr_sendmsg+0x680/0x9c0 net/qrtr/qrtr.c:960 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] sock_write_iter+0x317/0x470 net/socket.c:998 call_write_iter include/linux/fs.h:1882 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0xa96/0xd10 fs/read_write.c:578 ksys_write+0x11b/0x220 fs/read_write.c:631 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f84b5b81c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000038b40 RCX: 000000000045d5b9 RDX: 0000000000000055 RSI: 0000000020001240 RDI: 0000000000000003 RBP: 00007f84b5b81ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000f R13: 00007ffcbbf86daf R14: 00007f84b5b829c0 R15: 000000000118cf4c Allocated by task 4316: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 slab_post_alloc_hook+0x3e/0x290 mm/slab.h:518 slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x1c1/0x2d0 mm/slab.c:3482 skb_clone+0x1b2/0x370 net/core/skbuff.c:1449 qrtr_bcast_enqueue+0x6d/0x140 net/qrtr/qrtr.c:857 qrtr_sendmsg+0x680/0x9c0 net/qrtr/qrtr.c:960 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] sock_write_iter+0x317/0x470 net/socket.c:998 call_write_iter include/linux/fs.h:1882 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0xa96/0xd10 fs/read_write.c:578 ksys_write+0x11b/0x220 fs/read_write.c:631 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 4316: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free+0x82/0xf0 mm/slab.c:3693 __skb_pad+0x3f5/0x5a0 net/core/skbuff.c:1823 __skb_put_padto include/linux/skbuff.h:3233 [inline] skb_put_padto include/linux/skbuff.h:3252 [inline] qrtr_node_enqueue+0x62f/0xc00 net/qrtr/qrtr.c:360 qrtr_bcast_enqueue+0xbe/0x140 net/qrtr/qrtr.c:861 qrtr_sendmsg+0x680/0x9c0 net/qrtr/qrtr.c:960 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] sock_write_iter+0x317/0x470 net/socket.c:998 call_write_iter include/linux/fs.h:1882 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0xa96/0xd10 fs/read_write.c:578 ksys_write+0x11b/0x220 fs/read_write.c:631 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88804d8ab3c0 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 0 bytes inside of 224-byte region [ffff88804d8ab3c0, ffff88804d8ab4a0) The buggy address belongs to the page: page:00000000ea8cccfb refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804d8abb40 pfn:0x4d8ab flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002237ec8 ffffea00029b3388 ffff88821bb66800 raw: ffff88804d8abb40 ffff88804d8ab000 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Fixes: ce57785bf91b ("net: qrtr: fix len of skb_put_padto in qrtr_node_enqueue") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Carl Huang Cc: Wen Gong Cc: Bjorn Andersson Cc: Manivannan Sadhasivam Acked-by: Manivannan Sadhasivam Reviewed-by: Bjorn Andersson Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/qrtr/qrtr.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) --- a/net/qrtr/qrtr.c +++ b/net/qrtr/qrtr.c @@ -332,8 +332,7 @@ static int qrtr_node_enqueue(struct qrtr { struct qrtr_hdr_v1 *hdr; size_t len = skb->len; - int rc = -ENODEV; - int confirm_rx; + int rc, confirm_rx; confirm_rx = qrtr_tx_wait(node, to->sq_node, to->sq_port, type); if (confirm_rx < 0) { @@ -357,15 +356,17 @@ static int qrtr_node_enqueue(struct qrtr hdr->size = cpu_to_le32(len); hdr->confirm_rx = !!confirm_rx; - skb_put_padto(skb, ALIGN(len, 4) + sizeof(*hdr)); - - mutex_lock(&node->ep_lock); - if (node->ep) - rc = node->ep->xmit(node->ep, skb); - else - kfree_skb(skb); - mutex_unlock(&node->ep_lock); + rc = skb_put_padto(skb, ALIGN(len, 4) + sizeof(*hdr)); + if (!rc) { + mutex_lock(&node->ep_lock); + rc = -ENODEV; + if (node->ep) + rc = node->ep->xmit(node->ep, skb); + else + kfree_skb(skb); + mutex_unlock(&node->ep_lock); + } /* Need to ensure that a subsequent message carries the otherwise lost * confirm_rx flag if we dropped this one */ if (rc && confirm_rx)