CVE-2025-21899

{"id": "CVE-2025-21899", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "[email protected]", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2025-04-01T16:15:20.327", "references": [{"url": "https://git.kernel.org/stable/c/435d2964af815aae456db554c62963b4515f19d0", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/43b254d46c740bf9dbe65709afa021dd726dfa99", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/f1ae50cfb818ce1ac7a674406dfadb7653e2552d", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html", "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "[email protected]", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix bad hist from corrupting named_triggers list\n\nThe following commands causes a crash:\n\n ~# cd /sys/kernel/tracing/events/rcu/rcu_callback\n ~# echo 'hist:name=bad:keys=common_pid:onmax(bogus).save(common_pid)' > trigger\n bash: echo: write error: Invalid argument\n ~# echo 'hist:name=bad:keys=common_pid' > trigger\n\nBecause the following occurs:\n\nevent_trigger_write() {\n trigger_process_regex() {\n event_hist_trigger_parse() {\n\n data = event_trigger_alloc(..);\n\n event_trigger_register(.., data) {\n cmd_ops->reg(.., data, ..) [hist_register_trigger()] {\n data->ops->init() [event_hist_trigger_init()] {\n save_named_trigger(name, data) {\n list_add(&data->named_list, &named_triggers);\n }\n }\n }\n }\n\n ret = create_actions(); (return -EINVAL)\n if (ret)\n goto out_unreg;\n[..]\n ret = hist_trigger_enable(data, ...) {\n list_add_tail_rcu(&data->list, &file->triggers); <<<---- SKIPPED!!! (this is important!)\n[..]\n out_unreg:\n event_hist_unregister(.., data) {\n cmd_ops->unreg(.., data, ..) [hist_unregister_trigger()] {\n list_for_each_entry(iter, &file->triggers, list) {\n if (!hist_trigger_match(data, iter, named_data, false)) <- never matches\n continue;\n [..]\n test = iter;\n }\n if (test && test->ops->free) <<<-- test is NULL\n\n test->ops->free(test) [event_hist_trigger_free()] {\n [..]\n if (data->name)\n del_named_trigger(data) {\n list_del(&data->named_list); <<<<-- NEVER gets removed!\n }\n }\n }\n }\n\n [..]\n kfree(data); <<<-- frees item but it is still on list\n\nThe next time a hist with name is registered, it causes an u-a-f bug and\nthe kernel can crash.\n\nMove the code around such that if event_trigger_register() succeeds, the\nnext thing called is hist_trigger_enable() which adds it to the list.\n\nA bunch of actions is called if get_named_trigger_data() returns false.\nBut that doesn't need to be called after event_trigger_register(), so it\ncan be moved up, allowing event_trigger_register() to be called just\nbefore hist_trigger_enable() keeping them together and allowing the\nfile->triggers to be properly populated."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tracing: Fix bad hist from corrupting named_triggers list Los siguientes comandos provocan un bloqueo: ~# cd /sys/kernel/tracing/events/rcu/rcu_callback ~# echo 'hist:name=bad:keys=common_pid:onmax(bogus).save(common_pid)' &gt; trigger bash: echo: error de escritura: argumento no v\u00e1lido ~# echo 'hist:name=bad:keys=common_pid' &gt; trigger Porque ocurre lo siguiente: event_trigger_write() { trigger_process_regex() { event_hist_trigger_parse() { data = event_trigger_alloc(..); event_trigger_register(.., data) { cmd_ops-&gt;reg(.., data, ..) [hist_register_trigger()] { data-&gt;ops-&gt;init() [event_hist_trigger_init()] { save_named_trigger(name, data) { list_add(&amp;data-&gt;named_list, &amp;named_triggers); } } } } ret = create_actions(); (return -EINVAL) if (ret) goto out_unreg; [..] ret = hist_trigger_enable(data, ...) { list_add_tail_rcu(&amp;data-&gt;list, &amp;file-&gt;triggers); &lt;&lt;&lt;---- \u00a1\u00a1\u00a1SALTAR!!! (\u00a1esto es importante!) [..] out_unreg: event_hist_unregister(.., data) { cmd_ops-&gt;unreg(.., data, ..) [hist_unregister_trigger()] { list_for_each_entry(iter, &amp;file-&gt;triggers, list) { if (!hist_trigger_match(data, iter, named_data, false)) &lt;- never matches continue; [..] test = iter; } if (test &amp;&amp; test-&gt;ops-&gt;free) &lt;&lt;&lt;-- test is NULL test-&gt;ops-&gt;free(test) [event_hist_trigger_free()] { [..] if (data-&gt;name) del_named_trigger(data) { list_del(&amp;data-&gt;named_list); &lt;&lt;&lt;&lt;-- \u00a1NUNCA se elimina! } } } } [..] kfree(datos); &lt;&lt;&lt;-- libera el elemento, pero sigue en la lista. La pr\u00f3xima vez que se registre un hist con nombre, se producir\u00e1 un error de uaf y el kernel podr\u00eda bloquearse. Desplace el c\u00f3digo de forma que, si event_trigger_register() tiene \u00e9xito, se llame a hist_trigger_enable(), lo que lo a\u00f1ade a la lista. Se invocan varias acciones si get_named_trigger_data() devuelve falso. Sin embargo, no es necesario llamarlo despu\u00e9s de event_trigger_register(), por lo que se puede adelantar, lo que permite llamar a event_trigger_register() justo antes de hist_trigger_enable(), manteni\u00e9ndolos juntos y permitiendo que los disparadores de archivo se rellenen correctamente."}], "lastModified": "2025-11-03T20:17:25.817", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "9643A203-C3F3-4DA9-9231-44A49734AB6A", "versionEndExcluding": "6.1.130", "versionStartIncluding": "4.17"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8C92C9CD-2ADE-412E-A7FF-DC9E0630B25D", "versionEndExcluding": "6.6.81", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3D5C8D9A-4013-4C1A-810F-AA540BB5737C", "versionEndExcluding": "6.12.18", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "64F12D9B-71C2-4CD7-A288-0D5EF1709620", "versionEndExcluding": "6.13.6", "versionStartIncluding": "6.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "66619FB8-0AAF-4166-B2CF-67B24143261D"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D3D6550E-6679-4560-902D-AF52DCFE905B"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}