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CVE-2024-49949— net: avoid potential underflow in qdisc_pkt_len_init() with UFO

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net组件中qdisc_pkt_len_init函数在处理UFO时的潜在下溢问题。

AI Predicted 4.4 Difficulty: Hard EPSS 0.28% · P19

Affected Version Matrix 26

VendorProduct Version RangeStatus
Linux Linux 960b360ca7463921c1a6b72e7066a706d6406223< d70ca7598943572d5e384227bd268acb5109bf72 affected
fb2dbc124a7f800cd0e4f901a1bbb769a017104c< 1598d70ad9c7d0a4d9d54b82094e9f45908fda6d affected
8e6bae950da9dc2d2c6c18b1c6b206dc00dc8772< ba26060a29d3ca1bfc737aa79f7125128f35147c affected
0f810d06b507aa40fef8d1ac0a88e6d0590dbfc3< 939c88cbdc668dadd8cfa7a35d9066331239041c affected
cf9acc90c80ecbee00334aa85d92f4e74014bcff< d6114993e0a89fde84a60a60a8329a571580b174 affected
cf9acc90c80ecbee00334aa85d92f4e74014bcff< 25ab0b87dbd89cecef8a9c60a02bb97832e471d1 affected
cf9acc90c80ecbee00334aa85d92f4e74014bcff< f959cce8a2a04ce776aa8b78e83ce339e0d7fbac affected
cf9acc90c80ecbee00334aa85d92f4e74014bcff< 81fd007dcd47c34471766249853e4d4bce8eea4b affected
… +18 more rows
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I. Basic Information for CVE-2024-49949

Vulnerability Information
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Vulnerability Title
net: avoid potential underflow in qdisc_pkt_len_init() with UFO
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net: avoid potential underflow in qdisc_pkt_len_init() with UFO After commit 7c6d2ecbda83 ("net: be more gentle about silly gso requests coming from user") virtio_net_hdr_to_skb() had sanity check to detect malicious attempts from user space to cook a bad GSO packet. Then commit cf9acc90c80ec ("net: virtio_net_hdr_to_skb: count transport header in UFO") while fixing one issue, allowed user space to cook a GSO packet with the following characteristic : IPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28. When this packet arrives in qdisc_pkt_len_init(), we end up with hdr_len = 28 (IPv4 header + UDP header), matching skb->len Then the following sets gso_segs to 0 : gso_segs = DIV_ROUND_UP(skb->len - hdr_len, shinfo->gso_size); Then later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/ qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len; This leads to the following crash in fq_codel [1] qdisc_pkt_len_init() is best effort, we only want an estimation of the bytes sent on the wire, not crashing the kernel. This patch is fixing this particular issue, a following one adds more sanity checks for another potential bug. [1] [ 70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 70.724561] #PF: supervisor read access in kernel mode [ 70.724561] #PF: error_code(0x0000) - not-present page [ 70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0 [ 70.724561] Oops: Oops: 0000 [#1] SMP NOPTI [ 70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991 [ 70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel [ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49 All code ======== 0: 24 08 and $0x8,%al 2: 49 c1 e1 06 shl $0x6,%r9 6: 44 89 7c 24 18 mov %r15d,0x18(%rsp) b: 45 31 ed xor %r13d,%r13d e: 45 31 c0 xor %r8d,%r8d 11: 31 ff xor %edi,%edi 13: 89 44 24 14 mov %eax,0x14(%rsp) 17: 4c 03 8b 90 01 00 00 add 0x190(%rbx),%r9 1e: eb 04 jmp 0x24 20: 39 ca cmp %ecx,%edx 22: 73 37 jae 0x5b 24: 4d 8b 39 mov (%r9),%r15 27: 83 c7 01 add $0x1,%edi 2a:* 49 8b 17 mov (%r15),%rdx <-- trapping instruction 2d: 49 89 11 mov %rdx,(%r9) 30: 41 8b 57 28 mov 0x28(%r15),%edx 34: 45 8b 5f 34 mov 0x34(%r15),%r11d 38: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 3f: 49 rex.WB Code starting with the faulting instruction =========================================== 0: 49 8b 17 mov (%r15),%rdx 3: 49 89 11 mov %rdx,(%r9) 6: 41 8b 57 28 mov 0x28(%r15),%edx a: 45 8b 5f 34 mov 0x34(%r15),%r11d e: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 15: 49 rex.WB [ 70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202 [ 70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000 [ 70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 [ 70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000 [ 70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58 [ 70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000 [ 70.724561] FS: 000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000 [ 70.724561] CS: 0010 DS: 0000 ES: 0000 C ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
N/A
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net组件中qdisc_pkt_len_init函数在处理UFO时的潜在下溢问题。
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 960b360ca7463921c1a6b72e7066a706d6406223 ~ d70ca7598943572d5e384227bd268acb5109bf72 -
Linux Linux 5.16 -

II. Public POCs for CVE-2024-49949

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III. Intelligence Information for CVE-2024-49949

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Patches & Fixes for CVE-2024-49949 (9)

Same Patch Batch · Linux · 2024-10-21 · 372 CVEs total

CVE-2022-48985 9.8 CRITICAL net: mana: Fix race on per-CQ variable napi work_done
CVE-2024-47695 9.8 CRITICAL RDMA/rtrs-clt: Reset cid to con_num - 1 to stay in bounds
CVE-2024-50033 9.8 CRITICAL slip: make slhc_remember() more robust against malicious packets
CVE-2024-49855 9.8 CRITICAL nbd: fix race between timeout and normal completion
CVE-2024-50043 9.8 CRITICAL nfsd: fix possible badness in FREE_STATEID
CVE-2024-50047 9.8 CRITICAL smb: client: fix UAF in async decryption
CVE-2024-50046 9.8 CRITICAL NFSv4: Prevent NULL-pointer dereference in nfs42_complete_copies()
CVE-2022-49003 9.8 CRITICAL nvme: fix SRCU protection of nvme_ns_head list
CVE-2024-49996 9.4 CRITICAL cifs: Fix buffer overflow when parsing NFS reparse points
CVE-2024-47678 9.4 CRITICAL icmp: change the order of rate limits
CVE-2022-49017 8.8 HIGH tipc: re-fetch skb cb after tipc_msg_validate
CVE-2024-50029 8.8 HIGH Bluetooth: hci_conn: Fix UAF in hci_enhanced_setup_sync
CVE-2022-48954 8.8 HIGH s390/qeth: fix use-after-free in hsci
CVE-2022-48967 8.8 HIGH NFC: nci: Bounds check struct nfc_target arrays
CVE-2022-48964 8.8 HIGH ravb: Fix potential use-after-free in ravb_rx_gbeth()
CVE-2022-48960 8.8 HIGH net: hisilicon: Fix potential use-after-free in hix5hd2_rx()
CVE-2022-48962 8.8 HIGH net: hisilicon: Fix potential use-after-free in hisi_femac_rx()
CVE-2022-49015 8.8 HIGH net: hsr: Fix potential use-after-free
CVE-2024-49939 8.8 HIGH wifi: rtw89: avoid to add interface to list twice when SER
CVE-2024-49930 8.8 HIGH wifi: ath11k: fix array out-of-bound access in SoC stats

Showing top 20 of 372 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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