CVE-2021-47099 (GCVE-0-2021-47099)
Vulnerability from cvelistv5
Published
2024-03-04 18:10
Modified
2026-05-11 13:48
Severity ?
6.0 (Medium) - CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: veth: ensure skb entering GRO are not cloned. After commit d3256efd8e8b ("veth: allow enabling NAPI even without XDP"), if GRO is enabled on a veth device and TSO is disabled on the peer device, TCP skbs will go through the NAPI callback. If there is no XDP program attached, the veth code does not perform any share check, and shared/cloned skbs could enter the GRO engine. Ignat reported a BUG triggered later-on due to the above condition: [ 53.970529][ C1] kernel BUG at net/core/skbuff.c:3574! [ 53.981755][ C1] invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI [ 53.982634][ C1] CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.16.0-rc5+ #25 [ 53.982634][ C1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [ 53.982634][ C1] RIP: 0010:skb_shift+0x13ef/0x23b0 [ 53.982634][ C1] Code: ea 03 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 41 0c 00 00 41 80 7f 02 00 4d 8d b5 d0 00 00 00 0f 85 74 f5 ff ff <0f> 0b 4d 8d 77 20 be 04 00 00 00 4c 89 44 24 78 4c 89 f7 4c 89 8c [ 53.982634][ C1] RSP: 0018:ffff8881008f7008 EFLAGS: 00010246 [ 53.982634][ C1] RAX: 0000000000000000 RBX: ffff8881180b4c80 RCX: 0000000000000000 [ 53.982634][ C1] RDX: 0000000000000002 RSI: ffff8881180b4d3c RDI: ffff88810bc9cac2 [ 53.982634][ C1] RBP: ffff8881008f70b8 R08: ffff8881180b4cf4 R09: ffff8881180b4cf0 [ 53.982634][ C1] R10: ffffed1022999e5c R11: 0000000000000002 R12: 0000000000000590 [ 53.982634][ C1] R13: ffff88810f940c80 R14: ffff88810f940d50 R15: ffff88810bc9cac0 [ 53.982634][ C1] FS: 0000000000000000(0000) GS:ffff888235880000(0000) knlGS:0000000000000000 [ 53.982634][ C1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 53.982634][ C1] CR2: 00007ff5f9b86680 CR3: 0000000108ce8004 CR4: 0000000000170ee0 [ 53.982634][ C1] Call Trace: [ 53.982634][ C1] <TASK> [ 53.982634][ C1] tcp_sacktag_walk+0xaba/0x18e0 [ 53.982634][ C1] tcp_sacktag_write_queue+0xe7b/0x3460 [ 53.982634][ C1] tcp_ack+0x2666/0x54b0 [ 53.982634][ C1] tcp_rcv_established+0x4d9/0x20f0 [ 53.982634][ C1] tcp_v4_do_rcv+0x551/0x810 [ 53.982634][ C1] tcp_v4_rcv+0x22ed/0x2ed0 [ 53.982634][ C1] ip_protocol_deliver_rcu+0x96/0xaf0 [ 53.982634][ C1] ip_local_deliver_finish+0x1e0/0x2f0 [ 53.982634][ C1] ip_sublist_rcv_finish+0x211/0x440 [ 53.982634][ C1] ip_list_rcv_finish.constprop.0+0x424/0x660 [ 53.982634][ C1] ip_list_rcv+0x2c8/0x410 [ 53.982634][ C1] __netif_receive_skb_list_core+0x65c/0x910 [ 53.982634][ C1] netif_receive_skb_list_internal+0x5f9/0xcb0 [ 53.982634][ C1] napi_complete_done+0x188/0x6e0 [ 53.982634][ C1] gro_cell_poll+0x10c/0x1d0 [ 53.982634][ C1] __napi_poll+0xa1/0x530 [ 53.982634][ C1] net_rx_action+0x567/0x1270 [ 53.982634][ C1] __do_softirq+0x28a/0x9ba [ 53.982634][ C1] run_ksoftirqd+0x32/0x60 [ 53.982634][ C1] smpboot_thread_fn+0x559/0x8c0 [ 53.982634][ C1] kthread+0x3b9/0x490 [ 53.982634][ C1] ret_from_fork+0x22/0x30 [ 53.982634][ C1] </TASK> Address the issue by skipping the GRO stage for shared or cloned skbs. To reduce the chance of OoO, try to unclone the skbs before giving up. v1 -> v2: - use avoid skb_copy and fallback to netif_receive_skb - Eric
References
Impacted products
Vendor Product Version
Linux Linux Version: d3256efd8e8b234a6251e4d4580bd2c3c31fdc4c
Version: d3256efd8e8b234a6251e4d4580bd2c3c31fdc4c
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{
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            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 6,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "HIGH",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H",
              "version": "3.1"
            }
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              "content": {
                "id": "CVE-2021-47099",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-03-12T14:24:44.909749Z",
                "version": "2.0.3"
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              "type": "ssvc"
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                "type": "CWE"
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          "dateUpdated": "2024-10-31T14:56:58.471Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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        "title": "CISA ADP Vulnrichment"
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          "dateUpdated": "2024-08-04T05:24:39.924Z",
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            "url": "https://git.kernel.org/stable/c/9695b7de5b4760ed22132aca919570c0190cb0ce"
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        "title": "CVE Program Container"
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    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "d2269ae48598e05b59ec9ea9e6e44fd33941130d",
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          "product": "Linux",
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "5.13"
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: ensure skb entering GRO are not cloned.\n\nAfter commit d3256efd8e8b (\"veth: allow enabling NAPI even without XDP\"),\nif GRO is enabled on a veth device and TSO is disabled on the peer\ndevice, TCP skbs will go through the NAPI callback. If there is no XDP\nprogram attached, the veth code does not perform any share check, and\nshared/cloned skbs could enter the GRO engine.\n\nIgnat reported a BUG triggered later-on due to the above condition:\n\n[   53.970529][    C1] kernel BUG at net/core/skbuff.c:3574!\n[   53.981755][    C1] invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI\n[   53.982634][    C1] CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.16.0-rc5+ #25\n[   53.982634][    C1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n[   53.982634][    C1] RIP: 0010:skb_shift+0x13ef/0x23b0\n[   53.982634][    C1] Code: ea 03 0f b6 04 02 48 89 fa 83 e2 07 38 d0\n7f 08 84 c0 0f 85 41 0c 00 00 41 80 7f 02 00 4d 8d b5 d0 00 00 00 0f\n85 74 f5 ff ff \u003c0f\u003e 0b 4d 8d 77 20 be 04 00 00 00 4c 89 44 24 78 4c 89\nf7 4c 89 8c\n[   53.982634][    C1] RSP: 0018:ffff8881008f7008 EFLAGS: 00010246\n[   53.982634][    C1] RAX: 0000000000000000 RBX: ffff8881180b4c80 RCX: 0000000000000000\n[   53.982634][    C1] RDX: 0000000000000002 RSI: ffff8881180b4d3c RDI: ffff88810bc9cac2\n[   53.982634][    C1] RBP: ffff8881008f70b8 R08: ffff8881180b4cf4 R09: ffff8881180b4cf0\n[   53.982634][    C1] R10: ffffed1022999e5c R11: 0000000000000002 R12: 0000000000000590\n[   53.982634][    C1] R13: ffff88810f940c80 R14: ffff88810f940d50 R15: ffff88810bc9cac0\n[   53.982634][    C1] FS:  0000000000000000(0000) GS:ffff888235880000(0000) knlGS:0000000000000000\n[   53.982634][    C1] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   53.982634][    C1] CR2: 00007ff5f9b86680 CR3: 0000000108ce8004 CR4: 0000000000170ee0\n[   53.982634][    C1] Call Trace:\n[   53.982634][    C1]  \u003cTASK\u003e\n[   53.982634][    C1]  tcp_sacktag_walk+0xaba/0x18e0\n[   53.982634][    C1]  tcp_sacktag_write_queue+0xe7b/0x3460\n[   53.982634][    C1]  tcp_ack+0x2666/0x54b0\n[   53.982634][    C1]  tcp_rcv_established+0x4d9/0x20f0\n[   53.982634][    C1]  tcp_v4_do_rcv+0x551/0x810\n[   53.982634][    C1]  tcp_v4_rcv+0x22ed/0x2ed0\n[   53.982634][    C1]  ip_protocol_deliver_rcu+0x96/0xaf0\n[   53.982634][    C1]  ip_local_deliver_finish+0x1e0/0x2f0\n[   53.982634][    C1]  ip_sublist_rcv_finish+0x211/0x440\n[   53.982634][    C1]  ip_list_rcv_finish.constprop.0+0x424/0x660\n[   53.982634][    C1]  ip_list_rcv+0x2c8/0x410\n[   53.982634][    C1]  __netif_receive_skb_list_core+0x65c/0x910\n[   53.982634][    C1]  netif_receive_skb_list_internal+0x5f9/0xcb0\n[   53.982634][    C1]  napi_complete_done+0x188/0x6e0\n[   53.982634][    C1]  gro_cell_poll+0x10c/0x1d0\n[   53.982634][    C1]  __napi_poll+0xa1/0x530\n[   53.982634][    C1]  net_rx_action+0x567/0x1270\n[   53.982634][    C1]  __do_softirq+0x28a/0x9ba\n[   53.982634][    C1]  run_ksoftirqd+0x32/0x60\n[   53.982634][    C1]  smpboot_thread_fn+0x559/0x8c0\n[   53.982634][    C1]  kthread+0x3b9/0x490\n[   53.982634][    C1]  ret_from_fork+0x22/0x30\n[   53.982634][    C1]  \u003c/TASK\u003e\n\nAddress the issue by skipping the GRO stage for shared or cloned skbs.\nTo reduce the chance of OoO, try to unclone the skbs before giving up.\n\nv1 -\u003e v2:\n - use avoid skb_copy and fallback to netif_receive_skb  - Eric"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:48:02.475Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d2269ae48598e05b59ec9ea9e6e44fd33941130d"
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        {
          "url": "https://git.kernel.org/stable/c/9695b7de5b4760ed22132aca919570c0190cb0ce"
        }
      ],
      "title": "veth: ensure skb entering GRO are not cloned.",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47099",
    "datePublished": "2024-03-04T18:10:51.200Z",
    "dateReserved": "2024-02-29T22:33:44.301Z",
    "dateUpdated": "2026-05-11T13:48:02.475Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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