Date: Thu, 14 Dec 2023 10:34:20 -0500
From: Jamal Hadi Salim <jhs@...atatu.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Cong Wang <xiyou.wangcong@...il.com>, 
	Jiri Pirko <jiri@...nulli.us>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	syzbot <syzkaller@...glegroups.com>, Alexander Aring <aahringo@...hat.com>
Subject: Re: [PATCH net] net: sched: ife: fix potential use-after-free

On Thu, Dec 14, 2023 at 6:30 AM Eric Dumazet <edumazet@...gle.com> wrote:
>
> ife_decode() calls pskb_may_pull() two times, we need to reload
> ifehdr after the second one, or risk use-after-free as reported
> by syzbot:
>
> BUG: KASAN: slab-use-after-free in __ife_tlv_meta_valid net/ife/ife.c:108 [inline]
> BUG: KASAN: slab-use-after-free in ife_tlv_meta_decode+0x1d1/0x210 net/ife/ife.c:131
> Read of size 2 at addr ffff88802d7300a4 by task syz-executor.5/22323
>
> CPU: 0 PID: 22323 Comm: syz-executor.5 Not tainted 6.7.0-rc3-syzkaller-00804-g074ac38d5b95 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:364 [inline]
> print_report+0xc4/0x620 mm/kasan/report.c:475
> kasan_report+0xda/0x110 mm/kasan/report.c:588
> __ife_tlv_meta_valid net/ife/ife.c:108 [inline]
> ife_tlv_meta_decode+0x1d1/0x210 net/ife/ife.c:131
> tcf_ife_decode net/sched/act_ife.c:739 [inline]
> tcf_ife_act+0x4e3/0x1cd0 net/sched/act_ife.c:879
> tc_act include/net/tc_wrapper.h:221 [inline]
> tcf_action_exec+0x1ac/0x620 net/sched/act_api.c:1079
> tcf_exts_exec include/net/pkt_cls.h:344 [inline]
> mall_classify+0x201/0x310 net/sched/cls_matchall.c:42
> tc_classify include/net/tc_wrapper.h:227 [inline]
> __tcf_classify net/sched/cls_api.c:1703 [inline]
> tcf_classify+0x82f/0x1260 net/sched/cls_api.c:1800
> hfsc_classify net/sched/sch_hfsc.c:1147 [inline]
> hfsc_enqueue+0x315/0x1060 net/sched/sch_hfsc.c:1546
> dev_qdisc_enqueue+0x3f/0x230 net/core/dev.c:3739
> __dev_xmit_skb net/core/dev.c:3828 [inline]
> __dev_queue_xmit+0x1de1/0x3d30 net/core/dev.c:4311
> dev_queue_xmit include/linux/netdevice.h:3165 [inline]
> packet_xmit+0x237/0x350 net/packet/af_packet.c:276
> packet_snd net/packet/af_packet.c:3081 [inline]
> packet_sendmsg+0x24aa/0x5200 net/packet/af_packet.c:3113
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg+0xd5/0x180 net/socket.c:745
> __sys_sendto+0x255/0x340 net/socket.c:2190
> __do_sys_sendto net/socket.c:2202 [inline]
> __se_sys_sendto net/socket.c:2198 [inline]
> __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> RIP: 0033:0x7fe9acc7cae9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fe9ada450c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
> RAX: ffffffffffffffda RBX: 00007fe9acd9bf80 RCX: 00007fe9acc7cae9
> RDX: 000000000000fce0 RSI: 00000000200002c0 RDI: 0000000000000003
> RBP: 00007fe9accc847a R08: 0000000020000140 R09: 0000000000000014
> R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
> R13: 000000000000000b R14: 00007fe9acd9bf80 R15: 00007ffd5427ae78
> </TASK>
>
> Allocated by task 22323:
> kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
> kasan_set_track+0x25/0x30 mm/kasan/common.c:52
> ____kasan_kmalloc mm/kasan/common.c:374 [inline]
> __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
> kasan_kmalloc include/linux/kasan.h:198 [inline]
> __do_kmalloc_node mm/slab_common.c:1007 [inline]
> __kmalloc_node_track_caller+0x5a/0x90 mm/slab_common.c:1027
> kmalloc_reserve+0xef/0x260 net/core/skbuff.c:582
> __alloc_skb+0x12b/0x330 net/core/skbuff.c:651
> alloc_skb include/linux/skbuff.h:1298 [inline]
> alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6331
> sock_alloc_send_pskb+0x7e4/0x970 net/core/sock.c:2780
> packet_alloc_skb net/packet/af_packet.c:2930 [inline]
> packet_snd net/packet/af_packet.c:3024 [inline]
> packet_sendmsg+0x1e2a/0x5200 net/packet/af_packet.c:3113
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg+0xd5/0x180 net/socket.c:745
> __sys_sendto+0x255/0x340 net/socket.c:2190
> __do_sys_sendto net/socket.c:2202 [inline]
> __se_sys_sendto net/socket.c:2198 [inline]
> __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> Freed by task 22323:
> kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
> kasan_set_track+0x25/0x30 mm/kasan/common.c:52
> kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
> ____kasan_slab_free mm/kasan/common.c:236 [inline]
> ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
> kasan_slab_free include/linux/kasan.h:164 [inline]
> slab_free_hook mm/slub.c:1800 [inline]
> slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
> slab_free mm/slub.c:3809 [inline]
> __kmem_cache_free+0xc0/0x180 mm/slub.c:3822
> skb_kfree_head net/core/skbuff.c:950 [inline]
> skb_free_head+0x110/0x1b0 net/core/skbuff.c:962
> pskb_expand_head+0x3c5/0x1170 net/core/skbuff.c:2130
> __pskb_pull_tail+0xe1/0x1830 net/core/skbuff.c:2655
> pskb_may_pull_reason include/linux/skbuff.h:2685 [inline]
> pskb_may_pull include/linux/skbuff.h:2693 [inline]
> ife_decode+0x394/0x4f0 net/ife/ife.c:82
> tcf_ife_decode net/sched/act_ife.c:727 [inline]
> tcf_ife_act+0x43b/0x1cd0 net/sched/act_ife.c:879
> tc_act include/net/tc_wrapper.h:221 [inline]
> tcf_action_exec+0x1ac/0x620 net/sched/act_api.c:1079
> tcf_exts_exec include/net/pkt_cls.h:344 [inline]
> mall_classify+0x201/0x310 net/sched/cls_matchall.c:42
> tc_classify include/net/tc_wrapper.h:227 [inline]
> __tcf_classify net/sched/cls_api.c:1703 [inline]
> tcf_classify+0x82f/0x1260 net/sched/cls_api.c:1800
> hfsc_classify net/sched/sch_hfsc.c:1147 [inline]
> hfsc_enqueue+0x315/0x1060 net/sched/sch_hfsc.c:1546
> dev_qdisc_enqueue+0x3f/0x230 net/core/dev.c:3739
> __dev_xmit_skb net/core/dev.c:3828 [inline]
> __dev_queue_xmit+0x1de1/0x3d30 net/core/dev.c:4311
> dev_queue_xmit include/linux/netdevice.h:3165 [inline]
> packet_xmit+0x237/0x350 net/packet/af_packet.c:276
> packet_snd net/packet/af_packet.c:3081 [inline]
> packet_sendmsg+0x24aa/0x5200 net/packet/af_packet.c:3113
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg+0xd5/0x180 net/socket.c:745
> __sys_sendto+0x255/0x340 net/socket.c:2190
> __do_sys_sendto net/socket.c:2202 [inline]
> __se_sys_sendto net/socket.c:2198 [inline]
> __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> The buggy address belongs to the object at ffff88802d730000
> which belongs to the cache kmalloc-8k of size 8192
> The buggy address is located 164 bytes inside of
> freed 8192-byte region [ffff88802d730000, ffff88802d732000)
>
> The buggy address belongs to the physical page:
> page:ffffea0000b5cc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2d730
> head:ffffea0000b5cc00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> page_type: 0xffffffff()
> raw: 00fff00000000840 ffff888013042280 dead000000000122 0000000000000000
> raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 22323, tgid 22320 (syz-executor.5), ts 950317230369, free_ts 950233467461
> set_page_owner include/linux/page_owner.h:31 [inline]
> post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1544
> prep_new_page mm/page_alloc.c:1551 [inline]
> get_page_from_freelist+0xa28/0x3730 mm/page_alloc.c:3319
> __alloc_pages+0x22e/0x2420 mm/page_alloc.c:4575
> alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
> alloc_slab_page mm/slub.c:1870 [inline]
> allocate_slab mm/slub.c:2017 [inline]
> new_slab+0x283/0x3c0 mm/slub.c:2070
> ___slab_alloc+0x979/0x1500 mm/slub.c:3223
> __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
> __slab_alloc_node mm/slub.c:3375 [inline]
> slab_alloc_node mm/slub.c:3468 [inline]
> __kmem_cache_alloc_node+0x131/0x310 mm/slub.c:3517
> __do_kmalloc_node mm/slab_common.c:1006 [inline]
> __kmalloc_node_track_caller+0x4a/0x90 mm/slab_common.c:1027
> kmalloc_reserve+0xef/0x260 net/core/skbuff.c:582
> __alloc_skb+0x12b/0x330 net/core/skbuff.c:651
> alloc_skb include/linux/skbuff.h:1298 [inline]
> alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6331
> sock_alloc_send_pskb+0x7e4/0x970 net/core/sock.c:2780
> packet_alloc_skb net/packet/af_packet.c:2930 [inline]
> packet_snd net/packet/af_packet.c:3024 [inline]
> packet_sendmsg+0x1e2a/0x5200 net/packet/af_packet.c:3113
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg+0xd5/0x180 net/socket.c:745
> __sys_sendto+0x255/0x340 net/socket.c:2190
> page last free stack trace:
> reset_page_owner include/linux/page_owner.h:24 [inline]
> free_pages_prepare mm/page_alloc.c:1144 [inline]
> free_unref_page_prepare+0x53c/0xb80 mm/page_alloc.c:2354
> free_unref_page+0x33/0x3b0 mm/page_alloc.c:2494
> __unfreeze_partials+0x226/0x240 mm/slub.c:2655
> qlink_free mm/kasan/quarantine.c:168 [inline]
> qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
> kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:294
> __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
> kasan_slab_alloc include/linux/kasan.h:188 [inline]
> slab_post_alloc_hook mm/slab.h:763 [inline]
> slab_alloc_node mm/slub.c:3478 [inline]
> slab_alloc mm/slub.c:3486 [inline]
> __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
> kmem_cache_alloc_lru+0x219/0x6f0 mm/slub.c:3509
> alloc_inode_sb include/linux/fs.h:2937 [inline]
> ext4_alloc_inode+0x28/0x650 fs/ext4/super.c:1408
> alloc_inode+0x5d/0x220 fs/inode.c:261
> new_inode_pseudo fs/inode.c:1006 [inline]
> new_inode+0x22/0x260 fs/inode.c:1032
> __ext4_new_inode+0x333/0x5200 fs/ext4/ialloc.c:958
> ext4_symlink+0x5d7/0xa20 fs/ext4/namei.c:3398
> vfs_symlink fs/namei.c:4464 [inline]
> vfs_symlink+0x3e5/0x620 fs/namei.c:4448
> do_symlinkat+0x25f/0x310 fs/namei.c:4490
> __do_sys_symlinkat fs/namei.c:4506 [inline]
> __se_sys_symlinkat fs/namei.c:4503 [inline]
> __x64_sys_symlinkat+0x97/0xc0 fs/namei.c:4503
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
>
> Fixes: d57493d6d1be ("net: sched: ife: check on metadata length")
> Reported-by: syzbot <syzkaller@...glegroups.com>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>


Acked-by: Jamal Hadi Salim <jhs@...atatu.com>

cheers,
jamal

> Cc: Jamal Hadi Salim <jhs@...atatu.com>
> Cc: Alexander Aring <aahringo@...hat.com>
> ---
>  net/ife/ife.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/net/ife/ife.c b/net/ife/ife.c
> index 13bbf8cb6a3961d422d01cf5b16a724d16107419..be05b690b9ef29b3541e45af02f86f53b4b9681a 100644
> --- a/net/ife/ife.c
> +++ b/net/ife/ife.c
> @@ -82,6 +82,7 @@ void *ife_decode(struct sk_buff *skb, u16 *metalen)
>         if (unlikely(!pskb_may_pull(skb, total_pull)))
>                 return NULL;
>
> +       ifehdr = (struct ifeheadr *)(skb->data + skb->dev->hard_header_len);
>         skb_set_mac_header(skb, total_pull);
>         __skb_pull(skb, total_pull);
>         *metalen = ifehdrln - IFE_METAHDRLEN;
> --
> 2.43.0.472.g3155946c3a-goog
>

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