CVE-2022-50000
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2022-50000
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50000.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2022-50000
- Downstream
- Published
- 2025-06-18T11:00:59Z
- Modified
- 2025-10-21T11:43:54.367959Z
- Summary
- netfilter: flowtable: fix stuck flows on cleanup due to pending work
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: fix stuck flows on cleanup due to pending work
To clear the flow table on flow table free, the following sequence normally happens in order:
1) gcstep work is stopped to disable any further stats/del requests. 2) All flow table entries are set to teardown state. 3) Run gcstep which will queue HW del work for each flow table entry. 4) Waiting for the above del work to finish (flush). 5) Run gc_step again, deleting all entries from the flow table. 6) Flow table is freed.
But if a flow table entry already has pending HW stats or HW add work step 3 will not queue HW del work (it will be skipped), step 4 will wait for the pending add/stats to finish, and step 5 will queue HW del work which might execute after freeing of the flow table.
To fix the above, this patch flushes the pending work, then it sets the teardown flag to all flows in the flowtable and it forces a garbage collector run to queue work to remove the flows from hardware, then it flushes this new pending work and (finally) it forces another garbage collector run to remove the entry from the software flowtable.
Stack trace: [47773.882335] BUG: KASAN: use-after-free in downread+0x99/0x460 [47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704 [47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2 [47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009) [47773.888438] Workqueue: nfftoffloaddel flowoffloadworkhandler [nfflowtable] [47773.889727] Call Trace: [47773.890214] dumpstack+0xbb/0x107 [47773.890818] printaddressdescription.constprop.0+0x18/0x140 [47773.892990] kasanreport.cold+0x7c/0xd8 [47773.894459] kasancheckrange+0x145/0x1a0 [47773.895174] downread+0x99/0x460 [47773.899706] nfflowoffloadtuple+0x24f/0x3c0 [nfflowtable] [47773.907137] flowoffloadworkhandler+0x72d/0xbe0 [nfflowtable] [47773.913372] processonework+0x8ac/0x14e0 [47773.921325] [47773.921325] Allocated by task 592159: [47773.922031] kasansavestack+0x1b/0x40 [47773.922730] _kasankmalloc+0x7a/0x90 [47773.923411] tcfctflowtableget+0x3cb/0x1230 [actct] [47773.924363] tcfctinit+0x71c/0x1156 [actct] [47773.925207] tcfactioninit1+0x45b/0x700 [47773.925987] tcfactioninit+0x453/0x6b0 [47773.926692] tcfextsvalidate+0x3d0/0x600 [47773.927419] flchange+0x757/0x4a51 [clsflower] [47773.928227] tcnewtfilter+0x89a/0x2070 [47773.936652] [47773.936652] Freed by task 543704: [47773.937303] kasansavestack+0x1b/0x40 [47773.938039] kasansettrack+0x1c/0x30 [47773.938731] kasansetfreeinfo+0x20/0x30 [47773.939467] _kasanslabfree+0xe7/0x120 [47773.940194] slabfreefreelisthook+0x86/0x190 [47773.941038] kfree+0xce/0x3a0 [47773.941644] tcfctflowtablecleanup_work
Original patch description and stack trace by Paul Blakey.
- References
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc29f74e0df7a02b8303bcdce93a7c0132d62577aFixed8fbdec08dbf7d7ab8e35bdc65eb4394bc82d1e26
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc29f74e0df7a02b8303bcdce93a7c0132d62577aFixed89e135a36a9eb81412b5459df94a80995ce62eef
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc29f74e0df7a02b8303bcdce93a7c0132d62577aFixed9afb4b27349a499483ae0134282cefd0c90f480f
Affected versions
v5.*
v6.*
Database specific
vanir_signatures
[
{
"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@89e135a36a9eb81412b5459df94a80995ce62eef",
"target": {
"file": "include/net/netfilter/nf_flow_table.h"
},
"id": "CVE-2022-50000-0b3fbbb9",
"deprecated": false,
"digest": {
"line_hashes": [
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"threshold": 0.9
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"signature_version": "v1",
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{
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"target": {
"function": "nf_flow_table_free",
"file": "net/netfilter/nf_flow_table_core.c"
},
"id": "CVE-2022-50000-2e4e5c18",
"deprecated": false,
"digest": {
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"length": 346.0
},
"signature_version": "v1",
"signature_type": "Function"
},
{
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"target": {
"file": "include/net/netfilter/nf_flow_table.h"
},
"id": "CVE-2022-50000-4055cbf5",
"deprecated": false,
"digest": {
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"target": {
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},
"id": "CVE-2022-50000-4d697aba",
"deprecated": false,
"digest": {
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{
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"target": {
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},
"id": "CVE-2022-50000-65c335af",
"deprecated": false,
"digest": {
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{
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"target": {
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},
"id": "CVE-2022-50000-785dc10f",
"deprecated": false,
"digest": {
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},
"id": "CVE-2022-50000-78680622",
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"file": "net/netfilter/nf_flow_table_core.c"
},
"id": "CVE-2022-50000-b4f81aa9",
"deprecated": false,
"digest": {
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},
"id": "CVE-2022-50000-c7b88581",
"deprecated": false,
"digest": {
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]