CVE-2022-49093 (GCVE-0-2022-49093)

Vulnerability from cvelistv5 – Published: 2025-02-26 01:54 – Updated: 2025-05-04 08:29
VLAI?
Title
skbuff: fix coalescing for page_pool fragment recycling
Summary
In the Linux kernel, the following vulnerability has been resolved: skbuff: fix coalescing for page_pool fragment recycling Fix a use-after-free when using page_pool with page fragments. We encountered this problem during normal RX in the hns3 driver: (1) Initially we have three descriptors in the RX queue. The first one allocates PAGE1 through page_pool, and the other two allocate one half of PAGE2 each. Page references look like this: RX_BD1 _______ PAGE1 RX_BD2 _______ PAGE2 RX_BD3 _________/ (2) Handle RX on the first descriptor. Allocate SKB1, eventually added to the receive queue by tcp_queue_rcv(). (3) Handle RX on the second descriptor. Allocate SKB2 and pass it to netif_receive_skb(): netif_receive_skb(SKB2) ip_rcv(SKB2) SKB3 = skb_clone(SKB2) SKB2 and SKB3 share a reference to PAGE2 through skb_shinfo()->dataref. The other ref to PAGE2 is still held by RX_BD3: SKB2 ---+- PAGE2 SKB3 __/ / RX_BD3 _________/ (3b) Now while handling TCP, coalesce SKB3 with SKB1: tcp_v4_rcv(SKB3) tcp_try_coalesce(to=SKB1, from=SKB3) // succeeds kfree_skb_partial(SKB3) skb_release_data(SKB3) // drops one dataref SKB1 _____ PAGE1 \____ SKB2 _____ PAGE2 / RX_BD3 _________/ In skb_try_coalesce(), __skb_frag_ref() takes a page reference to PAGE2, where it should instead have increased the page_pool frag reference, pp_frag_count. Without coalescing, when releasing both SKB2 and SKB3, a single reference to PAGE2 would be dropped. Now when releasing SKB1 and SKB2, two references to PAGE2 will be dropped, resulting in underflow. (3c) Drop SKB2: af_packet_rcv(SKB2) consume_skb(SKB2) skb_release_data(SKB2) // drops second dataref page_pool_return_skb_page(PAGE2) // drops one pp_frag_count SKB1 _____ PAGE1 \____ PAGE2 / RX_BD3 _________/ (4) Userspace calls recvmsg() Copies SKB1 and releases it. Since SKB3 was coalesced with SKB1, we release the SKB3 page as well: tcp_eat_recv_skb(SKB1) skb_release_data(SKB1) page_pool_return_skb_page(PAGE1) page_pool_return_skb_page(PAGE2) // drops second pp_frag_count (5) PAGE2 is freed, but the third RX descriptor was still using it! In our case this causes IOMMU faults, but it would silently corrupt memory if the IOMMU was disabled. Change the logic that checks whether pp_recycle SKBs can be coalesced. We still reject differing pp_recycle between 'from' and 'to' SKBs, but in order to avoid the situation described above, we also reject coalescing when both 'from' and 'to' are pp_recycled and 'from' is cloned. The new logic allows coalescing a cloned pp_recycle SKB into a page refcounted one, because in this case the release (4) will drop the right reference, the one taken by skb_try_coalesce().
Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 53e0961da1c7bbdabd1abebb20de403ec237ec09 , < ba965e8605aee5387cecaa28fcf7ee9f61779a49 (git)
Affected: 53e0961da1c7bbdabd1abebb20de403ec237ec09 , < c4fa19615806a9a7e518c295b39175aa47a685ac (git)
Affected: 53e0961da1c7bbdabd1abebb20de403ec237ec09 , < 72bb856d16e883437023ff2ff77d0c498018728a (git)
Affected: 53e0961da1c7bbdabd1abebb20de403ec237ec09 , < 1effe8ca4e34c34cdd9318436a4232dcb582ebf4 (git)
Create a notification for this product.
    Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 5.15.34 , ≤ 5.15.* (semver)
Unaffected: 5.16.20 , ≤ 5.16.* (semver)
Unaffected: 5.17.3 , ≤ 5.17.* (semver)
Unaffected: 5.18 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2022-49093",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-02-27T18:17:26.547109Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-416",
                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-02-27T18:22:35.237Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ba965e8605aee5387cecaa28fcf7ee9f61779a49",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "c4fa19615806a9a7e518c295b39175aa47a685ac",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "72bb856d16e883437023ff2ff77d0c498018728a",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "1effe8ca4e34c34cdd9318436a4232dcb582ebf4",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.16.*",
              "status": "unaffected",
              "version": "5.16.20",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.17.*",
              "status": "unaffected",
              "version": "5.17.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.34",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.16.20",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.17.3",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.18",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nskbuff: fix coalescing for page_pool fragment recycling\n\nFix a use-after-free when using page_pool with page fragments. We\nencountered this problem during normal RX in the hns3 driver:\n\n(1) Initially we have three descriptors in the RX queue. The first one\n    allocates PAGE1 through page_pool, and the other two allocate one\n    half of PAGE2 each. Page references look like this:\n\n                RX_BD1 _______ PAGE1\n                RX_BD2 _______ PAGE2\n                RX_BD3 _________/\n\n(2) Handle RX on the first descriptor. Allocate SKB1, eventually added\n    to the receive queue by tcp_queue_rcv().\n\n(3) Handle RX on the second descriptor. Allocate SKB2 and pass it to\n    netif_receive_skb():\n\n    netif_receive_skb(SKB2)\n      ip_rcv(SKB2)\n        SKB3 = skb_clone(SKB2)\n\n    SKB2 and SKB3 share a reference to PAGE2 through\n    skb_shinfo()-\u003edataref. The other ref to PAGE2 is still held by\n    RX_BD3:\n\n                      SKB2 ---+- PAGE2\n                      SKB3 __/   /\n                RX_BD3 _________/\n\n (3b) Now while handling TCP, coalesce SKB3 with SKB1:\n\n      tcp_v4_rcv(SKB3)\n        tcp_try_coalesce(to=SKB1, from=SKB3)    // succeeds\n        kfree_skb_partial(SKB3)\n          skb_release_data(SKB3)                // drops one dataref\n\n                      SKB1 _____ PAGE1\n                           \\____\n                      SKB2 _____ PAGE2\n                                 /\n                RX_BD3 _________/\n\n    In skb_try_coalesce(), __skb_frag_ref() takes a page reference to\n    PAGE2, where it should instead have increased the page_pool frag\n    reference, pp_frag_count. Without coalescing, when releasing both\n    SKB2 and SKB3, a single reference to PAGE2 would be dropped. Now\n    when releasing SKB1 and SKB2, two references to PAGE2 will be\n    dropped, resulting in underflow.\n\n (3c) Drop SKB2:\n\n      af_packet_rcv(SKB2)\n        consume_skb(SKB2)\n          skb_release_data(SKB2)                // drops second dataref\n            page_pool_return_skb_page(PAGE2)    // drops one pp_frag_count\n\n                      SKB1 _____ PAGE1\n                           \\____\n                                 PAGE2\n                                 /\n                RX_BD3 _________/\n\n(4) Userspace calls recvmsg()\n    Copies SKB1 and releases it. Since SKB3 was coalesced with SKB1, we\n    release the SKB3 page as well:\n\n    tcp_eat_recv_skb(SKB1)\n      skb_release_data(SKB1)\n        page_pool_return_skb_page(PAGE1)\n        page_pool_return_skb_page(PAGE2)        // drops second pp_frag_count\n\n(5) PAGE2 is freed, but the third RX descriptor was still using it!\n    In our case this causes IOMMU faults, but it would silently corrupt\n    memory if the IOMMU was disabled.\n\nChange the logic that checks whether pp_recycle SKBs can be coalesced.\nWe still reject differing pp_recycle between \u0027from\u0027 and \u0027to\u0027 SKBs, but\nin order to avoid the situation described above, we also reject\ncoalescing when both \u0027from\u0027 and \u0027to\u0027 are pp_recycled and \u0027from\u0027 is\ncloned.\n\nThe new logic allows coalescing a cloned pp_recycle SKB into a page\nrefcounted one, because in this case the release (4) will drop the right\nreference, the one taken by skb_try_coalesce()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T08:29:44.316Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ba965e8605aee5387cecaa28fcf7ee9f61779a49"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4fa19615806a9a7e518c295b39175aa47a685ac"
        },
        {
          "url": "https://git.kernel.org/stable/c/72bb856d16e883437023ff2ff77d0c498018728a"
        },
        {
          "url": "https://git.kernel.org/stable/c/1effe8ca4e34c34cdd9318436a4232dcb582ebf4"
        }
      ],
      "title": "skbuff: fix coalescing for page_pool fragment recycling",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49093",
    "datePublished": "2025-02-26T01:54:47.669Z",
    "dateReserved": "2025-02-26T01:49:39.249Z",
    "dateUpdated": "2025-05-04T08:29:44.316Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-02-26T01:54:47.669Z\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nskbuff: fix coalescing for page_pool fragment recycling\\n\\nFix a use-after-free when using page_pool with page fragments. We\\nencountered this problem during normal RX in the hns3 driver:\\n\\n(1) Initially we have three descriptors in the RX queue. The first one\\n    allocates PAGE1 through page_pool, and the other two allocate one\\n    half of PAGE2 each. Page references look like this:\\n\\n                RX_BD1 _______ PAGE1\\n                RX_BD2 _______ PAGE2\\n                RX_BD3 _________/\\n\\n(2) Handle RX on the first descriptor. Allocate SKB1, eventually added\\n    to the receive queue by tcp_queue_rcv().\\n\\n(3) Handle RX on the second descriptor. Allocate SKB2 and pass it to\\n    netif_receive_skb():\\n\\n    netif_receive_skb(SKB2)\\n      ip_rcv(SKB2)\\n        SKB3 = skb_clone(SKB2)\\n\\n    SKB2 and SKB3 share a reference to PAGE2 through\\n    skb_shinfo()-\u003edataref. The other ref to PAGE2 is still held by\\n    RX_BD3:\\n\\n                      SKB2 ---+- PAGE2\\n                      SKB3 __/   /\\n                RX_BD3 _________/\\n\\n (3b) Now while handling TCP, coalesce SKB3 with SKB1:\\n\\n      tcp_v4_rcv(SKB3)\\n        tcp_try_coalesce(to=SKB1, from=SKB3)    // succeeds\\n        kfree_skb_partial(SKB3)\\n          skb_release_data(SKB3)                // drops one dataref\\n\\n                      SKB1 _____ PAGE1\\n                           \\\\____\\n                      SKB2 _____ PAGE2\\n                                 /\\n                RX_BD3 _________/\\n\\n    In skb_try_coalesce(), __skb_frag_ref() takes a page reference to\\n    PAGE2, where it should instead have increased the page_pool frag\\n    reference, pp_frag_count. Without coalescing, when releasing both\\n    SKB2 and SKB3, a single reference to PAGE2 would be dropped. Now\\n    when releasing SKB1 and SKB2, two references to PAGE2 will be\\n    dropped, resulting in underflow.\\n\\n (3c) Drop SKB2:\\n\\n      af_packet_rcv(SKB2)\\n        consume_skb(SKB2)\\n          skb_release_data(SKB2)                // drops second dataref\\n            page_pool_return_skb_page(PAGE2)    // drops one pp_frag_count\\n\\n                      SKB1 _____ PAGE1\\n                           \\\\____\\n                                 PAGE2\\n                                 /\\n                RX_BD3 _________/\\n\\n(4) Userspace calls recvmsg()\\n    Copies SKB1 and releases it. Since SKB3 was coalesced with SKB1, we\\n    release the SKB3 page as well:\\n\\n    tcp_eat_recv_skb(SKB1)\\n      skb_release_data(SKB1)\\n        page_pool_return_skb_page(PAGE1)\\n        page_pool_return_skb_page(PAGE2)        // drops second pp_frag_count\\n\\n(5) PAGE2 is freed, but the third RX descriptor was still using it!\\n    In our case this causes IOMMU faults, but it would silently corrupt\\n    memory if the IOMMU was disabled.\\n\\nChange the logic that checks whether pp_recycle SKBs can be coalesced.\\nWe still reject differing pp_recycle between \u0027from\u0027 and \u0027to\u0027 SKBs, but\\nin order to avoid the situation described above, we also reject\\ncoalescing when both \u0027from\u0027 and \u0027to\u0027 are pp_recycled and \u0027from\u0027 is\\ncloned.\\n\\nThe new logic allows coalescing a cloned pp_recycle SKB into a page\\nrefcounted one, because in this case the release (4) will drop the right\\nreference, the one taken by skb_try_coalesce().\"}], \"affected\": [{\"product\": \"Linux\", \"vendor\": \"Linux\", \"defaultStatus\": \"unaffected\", \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"programFiles\": [\"net/core/skbuff.c\"], \"versions\": [{\"version\": \"53e0961da1c7bbdabd1abebb20de403ec237ec09\", \"lessThan\": \"ba965e8605aee5387cecaa28fcf7ee9f61779a49\", \"status\": \"affected\", \"versionType\": \"git\"}, {\"version\": \"53e0961da1c7bbdabd1abebb20de403ec237ec09\", \"lessThan\": \"c4fa19615806a9a7e518c295b39175aa47a685ac\", \"status\": \"affected\", \"versionType\": \"git\"}, {\"version\": \"53e0961da1c7bbdabd1abebb20de403ec237ec09\", \"lessThan\": \"72bb856d16e883437023ff2ff77d0c498018728a\", \"status\": \"affected\", \"versionType\": \"git\"}, {\"version\": \"53e0961da1c7bbdabd1abebb20de403ec237ec09\", \"lessThan\": \"1effe8ca4e34c34cdd9318436a4232dcb582ebf4\", \"status\": \"affected\", \"versionType\": \"git\"}]}, {\"product\": \"Linux\", \"vendor\": \"Linux\", \"defaultStatus\": \"affected\", \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"programFiles\": [\"net/core/skbuff.c\"], \"versions\": [{\"version\": \"5.15\", \"status\": \"affected\"}, {\"version\": \"0\", \"lessThan\": \"5.15\", \"status\": \"unaffected\", \"versionType\": \"semver\"}, {\"version\": \"5.15.34\", \"lessThanOrEqual\": \"5.15.*\", \"status\": \"unaffected\", \"versionType\": \"semver\"}, {\"version\": \"5.16.20\", \"lessThanOrEqual\": \"5.16.*\", \"status\": \"unaffected\", \"versionType\": \"semver\"}, {\"version\": \"5.17.3\", \"lessThanOrEqual\": \"5.17.*\", \"status\": \"unaffected\", \"versionType\": \"semver\"}, {\"version\": \"5.18\", \"lessThanOrEqual\": \"*\", \"status\": \"unaffected\", \"versionType\": \"original_commit_for_fix\"}]}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/ba965e8605aee5387cecaa28fcf7ee9f61779a49\"}, {\"url\": \"https://git.kernel.org/stable/c/c4fa19615806a9a7e518c295b39175aa47a685ac\"}, {\"url\": \"https://git.kernel.org/stable/c/72bb856d16e883437023ff2ff77d0c498018728a\"}, {\"url\": \"https://git.kernel.org/stable/c/1effe8ca4e34c34cdd9318436a4232dcb582ebf4\"}], \"title\": \"skbuff: fix coalescing for page_pool fragment recycling\", \"x_generator\": {\"engine\": \"bippy-5f407fcff5a0\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.8, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2022-49093\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-02-27T18:17:26.547109Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-416\", \"description\": \"CWE-416 Use After Free\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-02-27T18:17:27.887Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2022-49093\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"Linux\", \"dateReserved\": \"2025-02-26T01:49:39.249Z\", \"datePublished\": \"2025-02-26T01:54:47.669Z\", \"dateUpdated\": \"2025-02-27T18:22:35.237Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • 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.