From patchwork Tue Aug 20 16:08:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13770446 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 09CB773176 for ; Tue, 20 Aug 2024 16:09:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724170144; cv=none; b=rbacPfj2b8DPrJ2QvTzsZzX9Zz+tYfwp5senk2Tg0tQ0DykLV0MwlWnL7UXVn4qTTcEuttT89YokgEAej10A9G9isF6t88Ad20z98rTuhFhp/jrke5dDw0ioiV08Jivwri9aVWw/EwJo0XbflkLdfh1hX2nTfbOTTvGFzNSHViw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724170144; c=relaxed/simple; bh=yS1UHtxKu2vJvZldY7H0NQ3WDbNnEubzUtpgcSV5t28=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=LBZa++JP2EgYwrpoAoEzSozDokkGQ8nhbTlFbspyXWiOUxF4JJtVP+LlTehWmX2yTIeOYE56NhHnRGI5QZZGKFZ+MUve23O6MPoOXa76/0oajreXGafvmiJN8VyXKCw3Wdb685zDOq/v9cRf5nxU4LASD9dUnRdPuqJR99+4nqk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=pqHa9hmD; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pqHa9hmD" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e164e64efb6so1717583276.3 for ; Tue, 20 Aug 2024 09:09:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1724170142; x=1724774942; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=SnUUgkJ/RsB+uQyEP8JntMqtRgYYJBc8/3pB/5cqAv4=; b=pqHa9hmDsNshQulofO2nr/d77xS11w8KY5CLH+zMjxsai1hOVGox6Z16Z5JO945L8b x1RUnu4IcilDF2fCe645KHpfvkF9vw8D7eagWFDz0/jlmNeygvHXs7QLeTUtV/lRX0DC KJKFOyzLhEn9E0Y3rWhdNomKRDGuEnBOVAD6/mlfyihHepLySEI0aFsKLISwpJvTbhqH cDWoDdhZrVAd3QrFDlCsjrEvKesEoBl3+/WSi1RL4RnnTrDoOhxzvLysemmMm2QRYxnc NZ6RCDPlUrnxP5Qk16y93QKvoc7KEfhc+MaUU+UiLq1Z63pEBFwC9VQ7ASB9P/0ViJsd BW1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724170142; x=1724774942; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=SnUUgkJ/RsB+uQyEP8JntMqtRgYYJBc8/3pB/5cqAv4=; b=mI8i4+r8f7I4FjRD/95l0TcVwGclQU2nbsdeaqbkrOLT/N+avVo1K2KKPkvRqHoC37 3sUl/qMImEApZ+tTBFXYjrHupnN9qLrkivb+KHjIM6wsVO0XPQ6qmIVWPRuXog5UoKO5 ebevEHdtI42UhVAnyPotUFPZEjxR8dAtFQnxNAGKV45xeSXzOWkmeGz5svHz55HOo490 81JTPIbmQtRaVUpOMm/c07GWRih/R+yFsQnchTvMpjWXR63/jxzjY82Q0SaRaPd8Zg5u LsHU2U7Npk5ZyaRy+aAOSGjZuiQ7KHNOKDzX3K2e78btaPIpAuYBucM6zWg41PxOW4r2 m1qA== X-Forwarded-Encrypted: i=1; AJvYcCU1qwOk9SSL6x3Bo71bZEKDM6+UEW3J6dhlkh7TurkA5+o9DxspMQ5xU6Zt1BD7kMnGN+E2YqduRQSQhNW+Qqjug4V5vubI X-Gm-Message-State: AOJu0YzelcWwRxJnWEGvAOD9Qoy0F4Hu56rh7LDXyd2WZ7ffYa/aE1Oe HpFF1yuPJG0KrJsgwkY3FeJfS6E6fNGOMrDG6JgwptSPmmVytPqkR37hMx0539WuH5oweNAzhrM rm1fWVVcUNA== X-Google-Smtp-Source: AGHT+IGbmtG7uoiV8kQRBcgvgVk7quhRDx0eaLkiSVBZ7hbTTbCuPeM6VeV+avGjla6i2RfhLXE0/sKOUHXoZg== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a25:bccd:0:b0:e0b:f1fd:1375 with SMTP id 3f1490d57ef6-e1180f732a0mr29064276.10.1724170141865; Tue, 20 Aug 2024 09:09:01 -0700 (PDT) Date: Tue, 20 Aug 2024 16:08:57 +0000 In-Reply-To: <20240820160859.3786976-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240820160859.3786976-1-edumazet@google.com> X-Mailer: git-send-email 2.46.0.184.g6999bdac58-goog Message-ID: <20240820160859.3786976-2-edumazet@google.com> Subject: [PATCH v2 net 1/3] ipv6: prevent UAF in ip6_send_skb() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: David Ahern , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot X-Patchwork-Delegate: kuba@kernel.org syzbot reported an UAF in ip6_send_skb() [1] After ip6_local_out() has returned, we no longer can safely dereference rt, unless we hold rcu_read_lock(). A similar issue has been fixed in commit a688caa34beb ("ipv6: take rcu lock in rawv6_send_hdrinc()") Another potential issue in ip6_finish_output2() is handled in a separate patch. [1] BUG: KASAN: slab-use-after-free in ip6_send_skb+0x18d/0x230 net/ipv6/ip6_output.c:1964 Read of size 8 at addr ffff88806dde4858 by task syz.1.380/6530 CPU: 1 UID: 0 PID: 6530 Comm: syz.1.380 Not tainted 6.11.0-rc3-syzkaller-00306-gdf6cbc62cc9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 ip6_send_skb+0x18d/0x230 net/ipv6/ip6_output.c:1964 rawv6_push_pending_frames+0x75c/0x9e0 net/ipv6/raw.c:588 rawv6_sendmsg+0x19c7/0x23c0 net/ipv6/raw.c:926 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 sock_write_iter+0x2dd/0x400 net/socket.c:1160 do_iter_readv_writev+0x60a/0x890 vfs_writev+0x37c/0xbb0 fs/read_write.c:971 do_writev+0x1b1/0x350 fs/read_write.c:1018 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f936bf79e79 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f936cd7f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f936c115f80 RCX: 00007f936bf79e79 RDX: 0000000000000001 RSI: 0000000020000040 RDI: 0000000000000004 RBP: 00007f936bfe7916 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f936c115f80 R15: 00007fff2860a7a8 Allocated by task 6530: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3988 [inline] slab_alloc_node mm/slub.c:4037 [inline] kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044 dst_alloc+0x12b/0x190 net/core/dst.c:89 ip6_blackhole_route+0x59/0x340 net/ipv6/route.c:2670 make_blackhole net/xfrm/xfrm_policy.c:3120 [inline] xfrm_lookup_route+0xd1/0x1c0 net/xfrm/xfrm_policy.c:3313 ip6_dst_lookup_flow+0x13e/0x180 net/ipv6/ip6_output.c:1257 rawv6_sendmsg+0x1283/0x23c0 net/ipv6/raw.c:898 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 45: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2252 [inline] slab_free mm/slub.c:4473 [inline] kmem_cache_free+0x145/0x350 mm/slub.c:4548 dst_destroy+0x2ac/0x460 net/core/dst.c:124 rcu_do_batch kernel/rcu/tree.c:2569 [inline] rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2843 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541 __call_rcu_common kernel/rcu/tree.c:3106 [inline] call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210 refdst_drop include/net/dst.h:263 [inline] skb_dst_drop include/net/dst.h:275 [inline] nf_ct_frag6_queue net/ipv6/netfilter/nf_conntrack_reasm.c:306 [inline] nf_ct_frag6_gather+0xb9a/0x2080 net/ipv6/netfilter/nf_conntrack_reasm.c:485 ipv6_defrag+0x2c8/0x3c0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:67 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] __ip6_local_out+0x6fa/0x800 net/ipv6/output_core.c:143 ip6_local_out+0x26/0x70 net/ipv6/output_core.c:153 ip6_send_skb+0x112/0x230 net/ipv6/ip6_output.c:1959 rawv6_push_pending_frames+0x75c/0x9e0 net/ipv6/raw.c:588 rawv6_sendmsg+0x19c7/0x23c0 net/ipv6/raw.c:926 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 sock_write_iter+0x2dd/0x400 net/socket.c:1160 do_iter_readv_writev+0x60a/0x890 Fixes: 0625491493d9 ("ipv6: ip6_push_pending_frames() should increment IPSTATS_MIB_OUTDISCARDS") Signed-off-by: Eric Dumazet Reported-by: syzbot Reviewed-by: David Ahern --- net/ipv6/ip6_output.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index ab504d31f0cdd8dec9ab01bf9d6e6517307609cd..f7b53effc80f8b3b7a839f58097d021a11f9eb37 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1956,6 +1956,7 @@ int ip6_send_skb(struct sk_buff *skb) struct rt6_info *rt = dst_rt6_info(skb_dst(skb)); int err; + rcu_read_lock(); err = ip6_local_out(net, skb->sk, skb); if (err) { if (err > 0) @@ -1965,6 +1966,7 @@ int ip6_send_skb(struct sk_buff *skb) IPSTATS_MIB_OUTDISCARDS); } + rcu_read_unlock(); return err; }