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CVE-2024-50154— tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().

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，该漏洞源于内存释放后重用。

CVSS 9.8 · Critical EPSS 0.56% · P45

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< 106e457953315e476b3642ef24be25ed862aaba3 affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< c964bf65f80a14288d767023a1b300b30f5b9cd0 affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< 8459d61fbf24967839a70235165673148c7c7f17 affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< 5071beb59ee416e8ab456ac8647a4dabcda823b1 affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< 997ae8da14f1639ce6fb66a063dab54031cd61b3 affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< 51e34db64f4e43c7b055ccf881b7f3e0c31bb26d affected
83fccfc3940c4a2db90fd7e7079f5b465cd8c6af< e8c526f2bdf1845bedaf6a478816a3d06fa78b8f affected
d3a1196bfc462943694623412d8e03aaf172bdc1 affected
… +10 more rows
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I. Basic Information for CVE-2024-50154

Vulnerability Information
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Vulnerability Title
tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink(). Martin KaFai Lau reported use-after-free [0] in reqsk_timer_handler(). """ We are seeing a use-after-free from a bpf prog attached to trace_tcp_retransmit_synack. The program passes the req->sk to the bpf_sk_storage_get_tracing kernel helper which does check for null before using it. """ The commit 83fccfc3940c ("inet: fix potential deadlock in reqsk_queue_unlink()") added timer_pending() in reqsk_queue_unlink() not to call del_timer_sync() from reqsk_timer_handler(), but it introduced a small race window. Before the timer is called, expire_timers() calls detach_timer(timer, true) to clear timer->entry.pprev and marks it as not pending. If reqsk_queue_unlink() checks timer_pending() just after expire_timers() calls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will continue running and send multiple SYN+ACKs until it expires. The reported UAF could happen if req->sk is close()d earlier than the timer expiration, which is 63s by default. The scenario would be 1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(), but del_timer_sync() is missed 2. reqsk timer is executed and scheduled again 3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but reqsk timer still has another one, and inet_csk_accept() does not clear req->sk for non-TFO sockets 4. sk is close()d 5. reqsk timer is executed again, and BPF touches req->sk Let's not use timer_pending() by passing the caller context to __inet_csk_reqsk_queue_drop(). Note that reqsk timer is pinned, so the issue does not happen in most use cases. [1] [0] BUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0 Use-after-free read at 0x00000000a891fb3a (in kfence-#1): bpf_sk_storage_get_tracing+0x2e/0x1b0 bpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda bpf_trace_run2+0x4c/0xc0 tcp_rtx_synack+0xf9/0x100 reqsk_timer_handler+0xda/0x3d0 run_timer_softirq+0x292/0x8a0 irq_exit_rcu+0xf5/0x320 sysvec_apic_timer_interrupt+0x6d/0x80 asm_sysvec_apic_timer_interrupt+0x16/0x20 intel_idle_irq+0x5a/0xa0 cpuidle_enter_state+0x94/0x273 cpu_startup_entry+0x15e/0x260 start_secondary+0x8a/0x90 secondary_startup_64_no_verify+0xfa/0xfb kfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6 allocated by task 0 on cpu 9 at 260507.901592s: sk_prot_alloc+0x35/0x140 sk_clone_lock+0x1f/0x3f0 inet_csk_clone_lock+0x15/0x160 tcp_create_openreq_child+0x1f/0x410 tcp_v6_syn_recv_sock+0x1da/0x700 tcp_check_req+0x1fb/0x510 tcp_v6_rcv+0x98b/0x1420 ipv6_list_rcv+0x2258/0x26e0 napi_complete_done+0x5b1/0x2990 mlx5e_napi_poll+0x2ae/0x8d0 net_rx_action+0x13e/0x590 irq_exit_rcu+0xf5/0x320 common_interrupt+0x80/0x90 asm_common_interrupt+0x22/0x40 cpuidle_enter_state+0xfb/0x273 cpu_startup_entry+0x15e/0x260 start_secondary+0x8a/0x90 secondary_startup_64_no_verify+0xfa/0xfb freed by task 0 on cpu 9 at 260507.927527s: rcu_core_si+0x4ff/0xf10 irq_exit_rcu+0xf5/0x320 sysvec_apic_timer_interrupt+0x6d/0x80 asm_sysvec_apic_timer_interrupt+0x16/0x20 cpuidle_enter_state+0xfb/0x273 cpu_startup_entry+0x15e/0x260 start_secondary+0x8a/0x90 secondary_startup_64_no_verify+0xfa/0xfb
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，该漏洞源于内存释放后重用。
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 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af ~ 106e457953315e476b3642ef24be25ed862aaba3 -
Linux Linux 4.2 -

II. Public POCs for CVE-2024-50154

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III. Intelligence Information for CVE-2024-50154

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Patches & Fixes for CVE-2024-50154 (7)

Same Patch Batch · Linux · 2024-11-07 · 34 CVEs total

CVE-2024-50162 9.8 CRITICAL bpf: devmap: provide rxq after redirect
CVE-2024-50152 9.8 CRITICAL smb: client: fix possible double free in smb2_set_ea()
CVE-2024-50139 7.9 HIGH KVM: arm64: Fix shift-out-of-bounds bug
CVE-2024-50150 7.8 HIGH usb: typec: altmode should keep reference to parent
CVE-2024-50161 7.8 HIGH bpf: Check the remaining info_cnt before repeating btf fields
CVE-2024-50158 7.8 HIGH RDMA/bnxt_re: Fix out of bound check
CVE-2024-50164 7.8 HIGH bpf: Fix overloading of MEM_UNINIT's meaning
CVE-2024-50165 7.8 HIGH bpf: Preserve param->string when parsing mount options
CVE-2024-50151 7.8 HIGH smb: client: fix OOBs when building SMB2_IOCTL request
CVE-2024-50149 7.8 HIGH drm/xe: Don't free job in TDR
CVE-2024-50143 7.8 HIGH udf: fix uninit-value use in udf_get_fileshortad
CVE-2024-50141 7.8 HIGH ACPI: PRM: Find EFI_MEMORY_RUNTIME block for PRM handler and context
CVE-2024-50145 7.5 HIGH octeon_ep: Add SKB allocation failures handling in __octep_oq_process_rx()
CVE-2024-50170 7.5 HIGH net: bcmasp: fix potential memory leak in bcmasp_xmit()
CVE-2024-50159 7.0 HIGH firmware: arm_scmi: Fix the double free in scmi_debugfs_common_setup()
CVE-2024-50167 be2net: fix potential memory leak in be_xmit()
CVE-2024-50156 drm/msm: Avoid NULL dereference in msm_disp_state_print_regs()
CVE-2024-50168 net/sun3_82586: fix potential memory leak in sun3_82586_send_packet()
CVE-2024-50169 vsock: Update rx_bytes on read_skb()
CVE-2024-50166 fsl/fman: Fix refcount handling of fman-related devices

Showing top 20 of 34 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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