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[23.128.96.18]) by mx.google.com with ESMTP id s16si1991799ejr.170.2020.04.23.16.18.26; Thu, 23 Apr 2020 16:18:49 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729450AbgDWXNy (ORCPT + 99 others); Thu, 23 Apr 2020 19:13:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:49984 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728483AbgDWXGu (ORCPT ); Thu, 23 Apr 2020 19:06:50 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jRkvY-0004lu-3v; Fri, 24 Apr 2020 00:06:40 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvT-00E6u9-V9; Fri, 24 Apr 2020 00:06:35 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Eric Dumazet" , "syzbot" , "David S. Miller" Date: Fri, 24 Apr 2020 00:06:31 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 164/245] macvlan: do not assume mac_header is set in macvlan_broadcast() In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 96cc4b69581db68efc9749ef32e9cf8e0160c509 upstream. Use of eth_hdr() in tx path is error prone. Many drivers call skb_reset_mac_header() before using it, but others do not. Commit 6d1ccff62780 ("net: reset mac header in dev_start_xmit()") attempted to fix this generically, but commit d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option") brought back the macvlan bug. Lets add a new helper, so that tx paths no longer have to call skb_reset_mac_header() only to get a pointer to skb->data. Hopefully we will be able to revert 6d1ccff62780 ("net: reset mac header in dev_start_xmit()") and save few cycles in transmit fast path. BUG: KASAN: use-after-free in __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline] BUG: KASAN: use-after-free in mc_hash drivers/net/macvlan.c:251 [inline] BUG: KASAN: use-after-free in macvlan_broadcast+0x547/0x620 drivers/net/macvlan.c:277 Read of size 4 at addr ffff8880a4932401 by task syz-executor947/9579 CPU: 0 PID: 9579 Comm: syz-executor947 Not tainted 5.5.0-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145 __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline] mc_hash drivers/net/macvlan.c:251 [inline] macvlan_broadcast+0x547/0x620 drivers/net/macvlan.c:277 macvlan_queue_xmit drivers/net/macvlan.c:520 [inline] macvlan_start_xmit+0x402/0x77f drivers/net/macvlan.c:559 __netdev_start_xmit include/linux/netdevice.h:4447 [inline] netdev_start_xmit include/linux/netdevice.h:4461 [inline] dev_direct_xmit+0x419/0x630 net/core/dev.c:4079 packet_direct_xmit+0x1a9/0x250 net/packet/af_packet.c:240 packet_snd net/packet/af_packet.c:2966 [inline] packet_sendmsg+0x260d/0x6220 net/packet/af_packet.c:2991 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 __sys_sendto+0x262/0x380 net/socket.c:1985 __do_sys_sendto net/socket.c:1997 [inline] __se_sys_sendto net/socket.c:1993 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1993 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x442639 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 5b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc13549e08 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442639 RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000003 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000403bb0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 9389: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x163/0x770 mm/slab.c:3665 kmalloc include/linux/slab.h:561 [inline] tomoyo_realpath_from_path+0xc5/0x660 security/tomoyo/realpath.c:252 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1222 vfs_getattr+0x25/0x70 fs/stat.c:115 vfs_statx_fd+0x71/0xc0 fs/stat.c:145 vfs_fstat include/linux/fs.h:3265 [inline] __do_sys_newfstat+0x9b/0x120 fs/stat.c:378 __se_sys_newfstat fs/stat.c:375 [inline] __x64_sys_newfstat+0x54/0x80 fs/stat.c:375 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9389: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 tomoyo_realpath_from_path+0x1a7/0x660 security/tomoyo/realpath.c:289 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1222 vfs_getattr+0x25/0x70 fs/stat.c:115 vfs_statx_fd+0x71/0xc0 fs/stat.c:145 vfs_fstat include/linux/fs.h:3265 [inline] __do_sys_newfstat+0x9b/0x120 fs/stat.c:378 __se_sys_newfstat fs/stat.c:375 [inline] __x64_sys_newfstat+0x54/0x80 fs/stat.c:375 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a4932000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 1025 bytes inside of 4096-byte region [ffff8880a4932000, ffff8880a4933000) The buggy address belongs to the page: page:ffffea0002924c80 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0 raw: 00fffe0000010200 ffffea0002846208 ffffea00028f3888 ffff8880aa402000 raw: 0000000000000000 ffff8880a4932000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a4932300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4932380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a4932400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a4932480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4932500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fixes: b863ceb7ddce ("[NET]: Add macvlan driver") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/net/macvlan.c | 2 +- include/linux/if_ether.h | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -162,7 +162,7 @@ static void macvlan_broadcast(struct sk_ struct net_device *src, enum macvlan_mode mode) { - const struct ethhdr *eth = eth_hdr(skb); + const struct ethhdr *eth = skb_eth_hdr(skb); const struct macvlan_dev *vlan; struct sk_buff *nskb; unsigned int i; --- a/include/linux/if_ether.h +++ b/include/linux/if_ether.h @@ -28,6 +28,14 @@ static inline struct ethhdr *eth_hdr(con return (struct ethhdr *)skb_mac_header(skb); } +/* Prefer this version in TX path, instead of + * skb_reset_mac_header() + eth_hdr() + */ +static inline struct ethhdr *skb_eth_hdr(const struct sk_buff *skb) +{ + return (struct ethhdr *)skb->data; +} + int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr); extern ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len);