Vulnerability-Lookup

GHSA-6JF4-4JP9-4WMW

Vulnerability from github – Published: 2024-02-27 21:31 – Updated: 2024-04-10 21:30

Details

In the Linux kernel, the following vulnerability has been resolved:

net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets

when 'act_mirred' tries to fragment IPv4 packets that had been previously re-assembled using 'act_ct', splats like the following can be observed on kernels built with KASAN:

BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60 Read of size 1 at addr ffff888147009574 by task ping/947

CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 ip_do_fragment+0x1b03/0x1f60 sch_fragment+0x4bf/0xe40 tcf_mirred_act+0xc3d/0x11a0 [act_mirred] tcf_action_exec+0x104/0x3e0 fl_classify+0x49a/0x5e0 [cls_flower] tcf_classify_ingress+0x18a/0x820 __netif_receive_skb_core+0xae7/0x3340 __netif_receive_skb_one_core+0xb6/0x1b0 process_backlog+0x1ef/0x6c0 __napi_poll+0xaa/0x500 net_rx_action+0x702/0xac0 __do_softirq+0x1e4/0x97f do_softirq+0x71/0x90 __local_bh_enable_ip+0xdb/0xf0 ip_finish_output2+0x760/0x2120 ip_do_fragment+0x15a5/0x1f60 __ip_finish_output+0x4c2/0xea0 ip_output+0x1ca/0x4d0 ip_send_skb+0x37/0xa0 raw_sendmsg+0x1c4b/0x2d00 sock_sendmsg+0xdb/0x110 __sys_sendto+0x1d7/0x2b0 __x64_sys_sendto+0xdd/0x1b0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f82e13853eb Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89 RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003 RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0 R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0

The buggy address belongs to the page: page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009 flags: 0x17ffffc0001000(reserved) raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00

ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2 ^ ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2

for IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then, in the following call graph:

ip_do_fragment() ip_skb_dst_mtu() ip_dst_mtu_maybe_forward() ip_mtu_locked()

the pointer to struct dst_entry is used as pointer to struct rtable: this turns the access to struct members like rt_mtu_locked into an OOB read in the stack. Fix this changing the temporary variable used for IPv4 packets in sch_fragment(), similarly to what is done for IPv6 few lines below.

Severity

7.1 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2021-46954"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-27T19:04:06Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets\n\nwhen \u0027act_mirred\u0027 tries to fragment IPv4 packets that had been previously\nre-assembled using \u0027act_ct\u0027, splats like the following can be observed on\nkernels built with KASAN:\n\n BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60\n Read of size 1 at addr ffff888147009574 by task ping/947\n\n CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418\n Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014\n Call Trace:\n  \u003cIRQ\u003e\n  dump_stack+0x92/0xc1\n  print_address_description.constprop.7+0x1a/0x150\n  kasan_report.cold.13+0x7f/0x111\n  ip_do_fragment+0x1b03/0x1f60\n  sch_fragment+0x4bf/0xe40\n  tcf_mirred_act+0xc3d/0x11a0 [act_mirred]\n  tcf_action_exec+0x104/0x3e0\n  fl_classify+0x49a/0x5e0 [cls_flower]\n  tcf_classify_ingress+0x18a/0x820\n  __netif_receive_skb_core+0xae7/0x3340\n  __netif_receive_skb_one_core+0xb6/0x1b0\n  process_backlog+0x1ef/0x6c0\n  __napi_poll+0xaa/0x500\n  net_rx_action+0x702/0xac0\n  __do_softirq+0x1e4/0x97f\n  do_softirq+0x71/0x90\n  \u003c/IRQ\u003e\n  __local_bh_enable_ip+0xdb/0xf0\n  ip_finish_output2+0x760/0x2120\n  ip_do_fragment+0x15a5/0x1f60\n  __ip_finish_output+0x4c2/0xea0\n  ip_output+0x1ca/0x4d0\n  ip_send_skb+0x37/0xa0\n  raw_sendmsg+0x1c4b/0x2d00\n  sock_sendmsg+0xdb/0x110\n  __sys_sendto+0x1d7/0x2b0\n  __x64_sys_sendto+0xdd/0x1b0\n  do_syscall_64+0x33/0x40\n  entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f82e13853eb\n Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89\n RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\n RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb\n RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003\n RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010\n R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0\n R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0\n\n The buggy address belongs to the page:\n page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009\n flags: 0x17ffffc0001000(reserved)\n raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000\n raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00\n \u003effff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2\n                                                              ^\n  ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2\n\nfor IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,\nin the following call graph:\n\n  ip_do_fragment()\n    ip_skb_dst_mtu()\n      ip_dst_mtu_maybe_forward()\n        ip_mtu_locked()\n\nthe pointer to struct dst_entry is used as pointer to struct rtable: this\nturns the access to struct members like rt_mtu_locked into an OOB read in\nthe stack. Fix this changing the temporary variable used for IPv4 packets\nin sch_fragment(), similarly to what is done for IPv6 few lines below.",
  "id": "GHSA-6jf4-4jp9-4wmw",
  "modified": "2024-04-10T21:30:29Z",
  "published": "2024-02-27T21:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46954"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/018bb8da5b5888e19585f9b802f036afe643fcef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/31fe34a0118e0acc958c802e830ad5d37ef6b1d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8e6dfb7beeb6489ac1365b8a71052e737f5da76e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2021-46954 (GCVE-0-2021-46954)

Vulnerability from cvelistv5 – Published: 2024-02-27 18:46 – Updated: 2026-05-11 13:45

Title

net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets when 'act_mirred' tries to fragment IPv4 packets that had been previously re-assembled using 'act_ct', splats like the following can be observed on kernels built with KASAN: BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60 Read of size 1 at addr ffff888147009574 by task ping/947 CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: <IRQ> dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 ip_do_fragment+0x1b03/0x1f60 sch_fragment+0x4bf/0xe40 tcf_mirred_act+0xc3d/0x11a0 [act_mirred] tcf_action_exec+0x104/0x3e0 fl_classify+0x49a/0x5e0 [cls_flower] tcf_classify_ingress+0x18a/0x820 __netif_receive_skb_core+0xae7/0x3340 __netif_receive_skb_one_core+0xb6/0x1b0 process_backlog+0x1ef/0x6c0 __napi_poll+0xaa/0x500 net_rx_action+0x702/0xac0 __do_softirq+0x1e4/0x97f do_softirq+0x71/0x90 </IRQ> __local_bh_enable_ip+0xdb/0xf0 ip_finish_output2+0x760/0x2120 ip_do_fragment+0x15a5/0x1f60 __ip_finish_output+0x4c2/0xea0 ip_output+0x1ca/0x4d0 ip_send_skb+0x37/0xa0 raw_sendmsg+0x1c4b/0x2d00 sock_sendmsg+0xdb/0x110 __sys_sendto+0x1d7/0x2b0 __x64_sys_sendto+0xdd/0x1b0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f82e13853eb Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89 RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003 RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0 R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0 The buggy address belongs to the page: page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009 flags: 0x17ffffc0001000(reserved) raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 >ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2 ^ ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 for IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then, in the following call graph: ip_do_fragment() ip_skb_dst_mtu() ip_dst_mtu_maybe_forward() ip_mtu_locked() the pointer to struct dst_entry is used as pointer to struct rtable: this turns the access to struct members like rt_mtu_locked into an OOB read in the stack. Fix this changing the temporary variable used for IPv4 packets in sch_fragment(), similarly to what is done for IPv6 few lines below.

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-02-27 19:36 UTC

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/018bb8da5b5888e19…
https://git.kernel.org/stable/c/8e6dfb7beeb6489ac…
https://git.kernel.org/stable/c/31fe34a0118e0acc9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c129412f74e99b609f0a8e95fc3915af1fd40f34 , < 018bb8da5b5888e19585f9b802f036afe643fcef (git) Affected: c129412f74e99b609f0a8e95fc3915af1fd40f34 , < 8e6dfb7beeb6489ac1365b8a71052e737f5da76e (git) Affected: c129412f74e99b609f0a8e95fc3915af1fd40f34 , < 31fe34a0118e0acc958c802e830ad5d37ef6b1d3 (git)
Linux	Linux	Affected: 5.11 Unaffected: 0 , < 5.11 (semver) Unaffected: 5.11.20 , ≤ 5.11.* (semver) Unaffected: 5.12.3 , ≤ 5.12.* (semver) Unaffected: 5.13 , ≤ * (original_commit_for_fix)

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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets\n\nwhen \u0027act_mirred\u0027 tries to fragment IPv4 packets that had been previously\nre-assembled using \u0027act_ct\u0027, splats like the following can be observed on\nkernels built with KASAN:\n\n BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60\n Read of size 1 at addr ffff888147009574 by task ping/947\n\n CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418\n Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014\n Call Trace:\n  \u003cIRQ\u003e\n  dump_stack+0x92/0xc1\n  print_address_description.constprop.7+0x1a/0x150\n  kasan_report.cold.13+0x7f/0x111\n  ip_do_fragment+0x1b03/0x1f60\n  sch_fragment+0x4bf/0xe40\n  tcf_mirred_act+0xc3d/0x11a0 [act_mirred]\n  tcf_action_exec+0x104/0x3e0\n  fl_classify+0x49a/0x5e0 [cls_flower]\n  tcf_classify_ingress+0x18a/0x820\n  __netif_receive_skb_core+0xae7/0x3340\n  __netif_receive_skb_one_core+0xb6/0x1b0\n  process_backlog+0x1ef/0x6c0\n  __napi_poll+0xaa/0x500\n  net_rx_action+0x702/0xac0\n  __do_softirq+0x1e4/0x97f\n  do_softirq+0x71/0x90\n  \u003c/IRQ\u003e\n  __local_bh_enable_ip+0xdb/0xf0\n  ip_finish_output2+0x760/0x2120\n  ip_do_fragment+0x15a5/0x1f60\n  __ip_finish_output+0x4c2/0xea0\n  ip_output+0x1ca/0x4d0\n  ip_send_skb+0x37/0xa0\n  raw_sendmsg+0x1c4b/0x2d00\n  sock_sendmsg+0xdb/0x110\n  __sys_sendto+0x1d7/0x2b0\n  __x64_sys_sendto+0xdd/0x1b0\n  do_syscall_64+0x33/0x40\n  entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f82e13853eb\n Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89\n RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\n RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb\n RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003\n RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010\n R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0\n R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0\n\n The buggy address belongs to the page:\n page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009\n flags: 0x17ffffc0001000(reserved)\n raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000\n raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00\n \u003effff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2\n                                                              ^\n  ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2\n\nfor IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,\nin the following call graph:\n\n  ip_do_fragment()\n    ip_skb_dst_mtu()\n      ip_dst_mtu_maybe_forward()\n        ip_mtu_locked()\n\nthe pointer to struct dst_entry is used as pointer to struct rtable: this\nturns the access to struct members like rt_mtu_locked into an OOB read in\nthe stack. Fix this changing the temporary variable used for IPv4 packets\nin sch_fragment(), similarly to what is done for IPv6 few lines below."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:45:08.606Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/018bb8da5b5888e19585f9b802f036afe643fcef"
        },
        {
          "url": "https://git.kernel.org/stable/c/8e6dfb7beeb6489ac1365b8a71052e737f5da76e"
        },
        {
          "url": "https://git.kernel.org/stable/c/31fe34a0118e0acc958c802e830ad5d37ef6b1d3"
        }
      ],
      "title": "net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-46954",
    "datePublished": "2024-02-27T18:46:56.804Z",
    "dateReserved": "2024-02-27T18:42:55.937Z",
    "dateUpdated": "2026-05-11T13:45:08.606Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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