| From foo@baz Sat 11 Jan 2020 09:44:46 AM CET |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Mon, 6 Jan 2020 12:30:48 -0800 |
| Subject: macvlan: do not assume mac_header is set in macvlan_broadcast() |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit 96cc4b69581db68efc9749ef32e9cf8e0160c509 ] |
| |
| 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 <edumazet@google.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| 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 |
| @@ -233,7 +233,7 @@ 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); |