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CVE-2021-47103— inet: fully convert sk->sk_rx_dst to RCU rules

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于存在释放后重用。

CVSS 9.8 · Critical EPSS 0.95% · P60

Possible ATT&CK Techniques 1 AI

T1055 · Process Injection

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 41063e9dd11956f2d285e12e4342e1d232ba0ea2< 68c34ce11ef23328692aa35fa6aaafdd75913100 affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< 92e6e36ecd16808866ac6172b9491b5097cde449 affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< 75a578000ae5e511e5d0e8433c94a14d9c99c412 affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< c3bb4a7e8cbc984e1cdac0fe6af60e880214ed6e affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< f039b43cbaea5e0700980c2f0052da05a70782e0 affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< 0249a4b8a554f2eb6a27b62516fa50168584faa4 affected
41063e9dd11956f2d285e12e4342e1d232ba0ea2< 8f905c0e7354ef261360fb7535ea079b1082c105 affected
3.6 affected
… +8 more rows
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I. Basic Information for CVE-2021-47103

Vulnerability Information
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Vulnerability Title
inet: fully convert sk->sk_rx_dst to RCU rules
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: inet: fully convert sk->sk_rx_dst to RCU rules syzbot reported various issues around early demux, one being included in this changelog [1] sk->sk_rx_dst is using RCU protection without clearly documenting it. And following sequences in tcp_v4_do_rcv()/tcp_v6_do_rcv() are not following standard RCU rules. [a] dst_release(dst); [b] sk->sk_rx_dst = NULL; They look wrong because a delete operation of RCU protected pointer is supposed to clear the pointer before the call_rcu()/synchronize_rcu() guarding actual memory freeing. In some cases indeed, dst could be freed before [b] is done. We could cheat by clearing sk_rx_dst before calling dst_release(), but this seems the right time to stick to standard RCU annotations and debugging facilities. [1] BUG: KASAN: use-after-free in dst_check include/net/dst.h:470 [inline] BUG: KASAN: use-after-free in tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792 Read of size 2 at addr ffff88807f1cb73a by task syz-executor.5/9204 CPU: 0 PID: 9204 Comm: syz-executor.5 Not tainted 5.16.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:433 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 dst_check include/net/dst.h:470 [inline] tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792 ip_rcv_finish_core.constprop.0+0x15de/0x1e80 net/ipv4/ip_input.c:340 ip_list_rcv_finish.constprop.0+0x1b2/0x6e0 net/ipv4/ip_input.c:583 ip_sublist_rcv net/ipv4/ip_input.c:609 [inline] ip_list_rcv+0x34e/0x490 net/ipv4/ip_input.c:644 __netif_receive_skb_list_ptype net/core/dev.c:5508 [inline] __netif_receive_skb_list_core+0x549/0x8e0 net/core/dev.c:5556 __netif_receive_skb_list net/core/dev.c:5608 [inline] netif_receive_skb_list_internal+0x75e/0xd80 net/core/dev.c:5699 gro_normal_list net/core/dev.c:5853 [inline] gro_normal_list net/core/dev.c:5849 [inline] napi_complete_done+0x1f1/0x880 net/core/dev.c:6590 virtqueue_napi_complete drivers/net/virtio_net.c:339 [inline] virtnet_poll+0xca2/0x11b0 drivers/net/virtio_net.c:1557 __napi_poll+0xaf/0x440 net/core/dev.c:7023 napi_poll net/core/dev.c:7090 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7177 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 common_interrupt+0x52/0xc0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 RIP: 0033:0x7f5e972bfd57 Code: 39 d1 73 14 0f 1f 80 00 00 00 00 48 8b 50 f8 48 83 e8 08 48 39 ca 77 f3 48 39 c3 73 3e 48 89 13 48 8b 50 f8 48 89 38 49 8b 0e <48> 8b 3e 48 83 c3 08 48 83 c6 08 eb bc 48 39 d1 72 9e 48 39 d0 73 RSP: 002b:00007fff8a413210 EFLAGS: 00000283 RAX: 00007f5e97108990 RBX: 00007f5e97108338 RCX: ffffffff81d3aa45 RDX: ffffffff81d3aa45 RSI: 00007f5e97108340 RDI: ffffffff81d3aa45 RBP: 00007f5e97107eb8 R08: 00007f5e97108d88 R09: 0000000093c2e8d9 R10: 0000000000000000 R11: 0000000000000000 R12: 00007f5e97107eb0 R13: 00007f5e97108338 R14: 00007f5e97107ea8 R15: 0000000000000019 </TASK> Allocated by task 13: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247 dst_alloc+0x146/0x1f0 net/core/dst.c:92 rt_dst_alloc+0x73/0x430 net/ipv4/route.c:1613 ip_route_input_slow+0x1817/0x3a20 net/ipv4/route.c:234 ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于存在释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 41063e9dd11956f2d285e12e4342e1d232ba0ea2 ~ 68c34ce11ef23328692aa35fa6aaafdd75913100 -
Linux Linux 3.6 -

II. Public POCs for CVE-2021-47103

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III. Intelligence Information for CVE-2021-47103

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Other References for CVE-2021-47103 (7)

Same Patch Batch · Linux · 2024-03-04 · 26 CVEs total

CVE-2021-47107 9.8 CRITICAL NFSD: Fix READDIR buffer overflow
CVE-2021-47082 7.8 HIGH tun: avoid double free in tun_free_netdev
CVE-2021-47087 7.8 HIGH tee: optee: Fix incorrect page free bug
CVE-2021-47106 7.8 HIGH netfilter: nf_tables: fix use-after-free in nft_set_catchall_destroy()
CVE-2021-47094 7.8 HIGH KVM: x86/mmu: Don't advance iterator after restart due to yielding
CVE-2021-47099 7.8 HIGH veth: ensure skb entering GRO are not cloned.
CVE-2021-47083 7.1 HIGH pinctrl: mediatek: fix global-out-of-bounds issue
CVE-2021-47102 7.1 HIGH net: marvell: prestera: fix incorrect structure access
CVE-2021-47095 ipmi: ssif: initialize ssif_info->client early
CVE-2021-47108 drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf
CVE-2021-47105 ice: xsk: return xsk buffers back to pool when cleaning the ring
CVE-2021-47104 IB/qib: Fix memory leak in qib_user_sdma_queue_pkts()
CVE-2021-47101 asix: fix uninit-value in asix_mdio_read()
CVE-2021-47100 ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module
CVE-2021-47098 hwmon: (lm90) Prevent integer overflow/underflow in hysteresis calculations
CVE-2021-47097 Input: elantech - fix stack out of bound access in elantech_change_report_id()
CVE-2021-47096 ALSA: rawmidi - fix the uninitalized user_pversion
CVE-2024-26622 tomoyo: fix UAF write bug in tomoyo_write_control()
CVE-2021-47093 platform/x86: intel_pmc_core: fix memleak on registration failure
CVE-2021-47092 KVM: VMX: Always clear vmx->fail on emulation_required

Showing top 20 of 26 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47103

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