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CVE-2024-43887 (GCVE-0-2024-43887)

Vulnerability from cvelistv5 – Published: 2024-08-26 10:10 – Updated: 2026-05-11 20:31
VLAI
Title
net/tcp: Disable TCP-AO static key after RCU grace period
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tcp: Disable TCP-AO static key after RCU grace period The lifetime of TCP-AO static_key is the same as the last tcp_ao_info. On the socket destruction tcp_ao_info ceases to be with RCU grace period, while tcp-ao static branch is currently deferred destructed. The static key definition is : DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); which means that if RCU grace period is delayed by more than a second and tcp_ao_needed is in the process of disablement, other CPUs may yet see tcp_ao_info which atent dead, but soon-to-be. And that breaks the assumption of static_key_fast_inc_not_disabled(). See the comment near the definition: > * The caller must make sure that the static key can't get disabled while > * in this function. It doesn't patch jump labels, only adds a user to > * an already enabled static key. Originally it was introduced in commit eb8c507296f6 ("jump_label: Prevent key->enabled int overflow"), which is needed for the atomic contexts, one of which would be the creation of a full socket from a request socket. In that atomic context, it's known by the presence of the key (md5/ao) that the static branch is already enabled. So, the ref counter for that static branch is just incremented instead of holding the proper mutex. static_key_fast_inc_not_disabled() is just a helper for such usage case. But it must not be used if the static branch could get disabled in parallel as it's not protected by jump_label_mutex and as a result, races with jump_label_update() implementation details. Happened on netdev test-bot[1], so not a theoretical issue: [] jump_label: Fatal kernel bug, unexpected op at tcp_inbound_hash+0x1a7/0x870 [ffffffffa8c4e9b7] (eb 50 0f 1f 44 != 66 90 0f 1f 00)) size:2 type:1 [] ------------[ cut here ]------------ [] kernel BUG at arch/x86/kernel/jump_label.c:73! [] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI [] CPU: 3 PID: 243 Comm: kworker/3:3 Not tainted 6.10.0-virtme #1 [] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [] Workqueue: events jump_label_update_timeout [] RIP: 0010:__jump_label_patch+0x2f6/0x350 ... [] Call Trace: [] <TASK> [] arch_jump_label_transform_queue+0x6c/0x110 [] __jump_label_update+0xef/0x350 [] __static_key_slow_dec_cpuslocked.part.0+0x3c/0x60 [] jump_label_update_timeout+0x2c/0x40 [] process_one_work+0xe3b/0x1670 [] worker_thread+0x587/0xce0 [] kthread+0x28a/0x350 [] ret_from_fork+0x31/0x70 [] ret_from_fork_asm+0x1a/0x30 [] </TASK> [] Modules linked in: veth [] ---[ end trace 0000000000000000 ]--- [] RIP: 0010:__jump_label_patch+0x2f6/0x350 [1]: https://netdev-3.bots.linux.dev/vmksft-tcp-ao-dbg/results/696681/5-connect-deny-ipv6/stderr
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-10 15:32 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 67fa83f7c86a86913ab9cd5a13b4bebd8d2ebb43 , < 954d55a59b2501f4a9bd693b40ce45a1c46cb2b3 (git)
Affected: 67fa83f7c86a86913ab9cd5a13b4bebd8d2ebb43 , < 14ab4792ee120c022f276a7e4768f4dcb08f0cdd (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.10.5 , ≤ 6.10.* (semver)
Unaffected: 6.11 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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          "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: net/tcp: deshabilite la clave est\u00e1tica TCP-AO despu\u00e9s del per\u00edodo de gracia de RCU. La vida \u00fatil de TCP-AO static_key es la misma que la del \u00faltimo tcp_ao_info. En la destrucci\u00f3n del socket, tcp_ao_info deja de tener un per\u00edodo de gracia de RCU, mientras que la rama est\u00e1tica tcp-ao actualmente se retrasa su destrucci\u00f3n. La definici\u00f3n de clave est\u00e1tica es: DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); lo que significa que si el per\u00edodo de gracia de la RCU se retrasa m\u00e1s de un segundo y tcp_ao_needed est\u00e1 en proceso de deshabilitaci\u00f3n, es posible que otras CPU a\u00fan vean tcp_ao_info, que est\u00e1 muerto, pero pronto lo estar\u00e1. Y eso rompe la suposici\u00f3n de static_key_fast_inc_not_disabled(). Vea el comentario cerca de la definici\u00f3n: \u0026gt; * El que llama debe asegurarse de que la clave est\u00e1tica no puede conseguir desactivada mientras \u0026gt; * est\u00e1 en esta funci\u00f3n. No parchea etiquetas de salto, s\u00f3lo agrega un usuario a \u0026gt; * una clave est\u00e1tica ya habilitada. Originalmente se introdujo en el commit eb8c507296f6 (\"jump_label: Prevent key-\u0026gt;enabled int overflow\"), que es necesaria para los contextos at\u00f3micos, uno de los cuales ser\u00eda la creaci\u00f3n de un socket completo a partir de un socket de solicitud. En ese contexto at\u00f3mico, se sabe por la presencia de la clave (md5/ao) que la rama est\u00e1tica ya est\u00e1 habilitada. Entonces, el contador de referencia para esa rama est\u00e1tica simplemente se incrementa en lugar de mantener el mutex adecuado. static_key_fast_inc_not_disabled() es solo una ayuda para tal caso de uso. Pero no debe usarse si la rama est\u00e1tica podr\u00eda deshabilitarse en paralelo ya que no est\u00e1 protegida por jump_label_mutex y, como resultado, corre con los detalles de implementaci\u00f3n de jump_label_update(). Sucedi\u00f3 en netdev test-bot[1], por lo que no es un problema te\u00f3rico: [] jump_label: error fatal del kernel, operaci\u00f3n inesperada en tcp_inbound_hash+0x1a7/0x870 [ffffffffa8c4e9b7] (eb 50 0f 1f 44 != 66 90 0f 1f 00)) tama\u00f1o:2 tipo:1 [] ------------[ cortar aqu\u00ed ]------------ [] ERROR del kernel en arch/x86/kernel/jump_label.c :73! [] Ups: c\u00f3digo de operaci\u00f3n no v\u00e1lido: 0000 [#1] PREEMPT SMP KASAN NOPTI [] CPU: 3 PID: 243 Comm: kworker/3:3 Not tainted 6.10.0-virtme #1 [] Nombre del hardware: PC est\u00e1ndar QEMU (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 01/04/2014 [] Cola de trabajo: eventos jump_label_update_timeout [] RIP: 0010:__jump_label_patch+0x2f6/0x350... [] Llamada Seguimiento: []  [] arch_jump_label_transform_queue+0x6c/0x110 [] __jump_label_update+0xef/0x350 [] __static_key_slow_dec_cpuslocked.part.0+0x3c/0x60 [] jump_label_update_timeout+0x2c/0x40 [] 0x1670 [] hilo_trabajador+ 0x587/0xce0 [] kthread+0x28a/0x350 [] ret_from_fork+0x31/0x70 [] ret_from_fork_asm+0x1a/0x30 []  [] M\u00f3dulos vinculados en: veth [] ---[ end trace 0000000000000000 ]--- [] RIP: 0010:__jump_label_patch+0x2f6/0x350 [1]: https://netdev-3.bots.linux.dev/vmksft-tcp-ao-dbg/results/696681/5-connect-deny-ipv6/stderr"
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      "id": "CVE-2024-43887",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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        "configurations": [
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            "nodes": [
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                "cpeMatch": [
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Disable TCP-AO static key after RCU grace period\n\nThe lifetime of TCP-AO static_key is the same as the last\ntcp_ao_info. On the socket destruction tcp_ao_info ceases to be\nwith RCU grace period, while tcp-ao static branch is currently deferred\ndestructed. The static key definition is\n: DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ);\n\nwhich means that if RCU grace period is delayed by more than a second\nand tcp_ao_needed is in the process of disablement, other CPUs may\nyet see tcp_ao_info which atent dead, but soon-to-be.\nAnd that breaks the assumption of static_key_fast_inc_not_disabled().\n\nSee the comment near the definition:\n\u003e * The caller must make sure that the static key can\u0027t get disabled while\n\u003e * in this function. It doesn\u0027t patch jump labels, only adds a user to\n\u003e * an already enabled static key.\n\nOriginally it was introduced in commit eb8c507296f6 (\"jump_label:\nPrevent key-\u003eenabled int overflow\"), which is needed for the atomic\ncontexts, one of which would be the creation of a full socket from a\nrequest socket. In that atomic context, it\u0027s known by the presence\nof the key (md5/ao) that the static branch is already enabled.\nSo, the ref counter for that static branch is just incremented\ninstead of holding the proper mutex.\nstatic_key_fast_inc_not_disabled() is just a helper for such usage\ncase. But it must not be used if the static branch could get disabled\nin parallel as it\u0027s not protected by jump_label_mutex and as a result,\nraces with jump_label_update() implementation details.\n\nHappened on netdev test-bot[1], so not a theoretical issue:\n\n[] jump_label: Fatal kernel bug, unexpected op at tcp_inbound_hash+0x1a7/0x870 [ffffffffa8c4e9b7] (eb 50 0f 1f 44 != 66 90 0f 1f 00)) size:2 type:1\n[] ------------[ cut here ]------------\n[] kernel BUG at arch/x86/kernel/jump_label.c:73!\n[] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI\n[] CPU: 3 PID: 243 Comm: kworker/3:3 Not tainted 6.10.0-virtme #1\n[] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[] Workqueue: events jump_label_update_timeout\n[] RIP: 0010:__jump_label_patch+0x2f6/0x350\n...\n[] Call Trace:\n[]  \u003cTASK\u003e\n[]  arch_jump_label_transform_queue+0x6c/0x110\n[]  __jump_label_update+0xef/0x350\n[]  __static_key_slow_dec_cpuslocked.part.0+0x3c/0x60\n[]  jump_label_update_timeout+0x2c/0x40\n[]  process_one_work+0xe3b/0x1670\n[]  worker_thread+0x587/0xce0\n[]  kthread+0x28a/0x350\n[]  ret_from_fork+0x31/0x70\n[]  ret_from_fork_asm+0x1a/0x30\n[]  \u003c/TASK\u003e\n[] Modules linked in: veth\n[] ---[ end trace 0000000000000000 ]---\n[] RIP: 0010:__jump_label_patch+0x2f6/0x350\n\n[1]: https://netdev-3.bots.linux.dev/vmksft-tcp-ao-dbg/results/696681/5-connect-deny-ipv6/stderr"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: net/tcp: deshabilite la clave est\u00e1tica TCP-AO despu\u00e9s del per\u00edodo de gracia de RCU. La vida \u00fatil de TCP-AO static_key es la misma que la del \u00faltimo tcp_ao_info. En la destrucci\u00f3n del socket, tcp_ao_info deja de tener un per\u00edodo de gracia de RCU, mientras que la rama est\u00e1tica tcp-ao actualmente se retrasa su destrucci\u00f3n. La definici\u00f3n de clave est\u00e1tica es: DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); lo que significa que si el per\u00edodo de gracia de la RCU se retrasa m\u00e1s de un segundo y tcp_ao_needed est\u00e1 en proceso de deshabilitaci\u00f3n, es posible que otras CPU a\u00fan vean tcp_ao_info, que est\u00e1 muerto, pero pronto lo estar\u00e1. Y eso rompe la suposici\u00f3n de static_key_fast_inc_not_disabled(). Vea el comentario cerca de la definici\u00f3n: \u0026gt; * El que llama debe asegurarse de que la clave est\u00e1tica no puede conseguir desactivada mientras \u0026gt; * est\u00e1 en esta funci\u00f3n. No parchea etiquetas de salto, s\u00f3lo agrega un usuario a \u0026gt; * una clave est\u00e1tica ya habilitada. Originalmente se introdujo en el commit eb8c507296f6 (\"jump_label: Prevent key-\u0026gt;enabled int overflow\"), que es necesaria para los contextos at\u00f3micos, uno de los cuales ser\u00eda la creaci\u00f3n de un socket completo a partir de un socket de solicitud. En ese contexto at\u00f3mico, se sabe por la presencia de la clave (md5/ao) que la rama est\u00e1tica ya est\u00e1 habilitada. Entonces, el contador de referencia para esa rama est\u00e1tica simplemente se incrementa en lugar de mantener el mutex adecuado. static_key_fast_inc_not_disabled() es solo una ayuda para tal caso de uso. Pero no debe usarse si la rama est\u00e1tica podr\u00eda deshabilitarse en paralelo ya que no est\u00e1 protegida por jump_label_mutex y, como resultado, corre con los detalles de implementaci\u00f3n de jump_label_update(). Sucedi\u00f3 en netdev test-bot[1], por lo que no es un problema te\u00f3rico: [] jump_label: error fatal del kernel, operaci\u00f3n inesperada en tcp_inbound_hash+0x1a7/0x870 [ffffffffa8c4e9b7] (eb 50 0f 1f 44 != 66 90 0f 1f 00)) tama\u00f1o:2 tipo:1 [] ------------[ cortar aqu\u00ed ]------------ [] ERROR del kernel en arch/x86/kernel/jump_label.c :73! [] Ups: c\u00f3digo de operaci\u00f3n no v\u00e1lido: 0000 [#1] PREEMPT SMP KASAN NOPTI [] CPU: 3 PID: 243 Comm: kworker/3:3 Not tainted 6.10.0-virtme #1 [] Nombre del hardware: PC est\u00e1ndar QEMU (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 01/04/2014 [] Cola de trabajo: eventos jump_label_update_timeout [] RIP: 0010:__jump_label_patch+0x2f6/0x350... [] Llamada Seguimiento: []  [] arch_jump_label_transform_queue+0x6c/0x110 [] __jump_label_update+0xef/0x350 [] __static_key_slow_dec_cpuslocked.part.0+0x3c/0x60 [] jump_label_update_timeout+0x2c/0x40 [] 0x1670 [] hilo_trabajador+ 0x587/0xce0 [] kthread+0x28a/0x350 [] ret_from_fork+0x31/0x70 [] ret_from_fork_asm+0x1a/0x30 []  [] M\u00f3dulos vinculados en: veth [] ---[ end trace 0000000000000000 ]--- [] RIP: 0010:__jump_label_patch+0x2f6/0x350 [1]: https://netdev-3.bots.linux.dev/vmksft-tcp-ao-dbg/results/696681/5-connect-deny-ipv6/stderr"
          }
        ],
        "id": "CVE-2024-43887",
        "lastModified": "2026-06-17T07:51:55.903",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
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                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 4.7,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
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              "exploitabilityScore": 1.0,
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        "published": "2024-08-26T11:15:03.877",
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      "product_status:known_affected": "42",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/tcp: Disable TCP-AO static key after RCU grace period",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-43887.json",
      "version": "3"
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      "cve": "CVE-2024-43887",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2024-43887",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2024-43887.json",
      "version": "18"
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              "product": "Linux",
              "programFiles": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "vendor": "Linux",
              "versions": [
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                {
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                  "status": "unaffected",
                  "version": "6.11",
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          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Disable TCP-AO static key after RCU grace period\n\nThe lifetime of TCP-AO static_key is the same as the last\ntcp_ao_info. On the socket destruction tcp_ao_info ceases to be\nwith RCU grace period, while tcp-ao static branch is currently deferred\ndestructed. The static key definition is\n: DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ);\n\nwhich means that if RCU grace period is delayed by more than a second\nand tcp_ao_needed is in the process of disablement, other CPUs may\nyet see tcp_ao_info which atent dead, but soon-to-be.\nAnd that breaks the assumption of static_key_fast_inc_not_disabled().\n\nSee the comment near the definition:\n\u003e * The caller must make sure that the static key can\u0027t get disabled while\n\u003e * in this function. It doesn\u0027t patch jump labels, only adds a user to\n\u003e * an already enabled static key.\n\nOriginally it was introduced in commit eb8c507296f6 (\"jump_label:\nPrevent key-\u003eenabled int overflow\"), which is needed for the atomic\ncontexts, one of which would be the creation of a full socket from a\nrequest socket. In that atomic context, it\u0027s known by the presence\nof the key (md5/ao) that the static branch is already enabled.\nSo, the ref counter for that static branch is just incremented\ninstead of holding the proper mutex.\nstatic_key_fast_inc_not_disabled() is just a helper for such usage\ncase. But it must not be used if the static branch could get disabled\nin parallel as it\u0027s not protected by jump_label_mutex and as a result,\nraces with jump_label_update() implementation details.\n\nHappened on netdev test-bot[1], so not a theoretical issue:\n\n[] jump_label: Fatal kernel bug, unexpected op at tcp_inbound_hash+0x1a7/0x870 [ffffffffa8c4e9b7] (eb 50 0f 1f 44 != 66 90 0f 1f 00)) size:2 type:1\n[] ------------[ cut here ]------------\n[] kernel BUG at arch/x86/kernel/jump_label.c:73!\n[] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI\n[] CPU: 3 PID: 243 Comm: kworker/3:3 Not tainted 6.10.0-virtme #1\n[] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[] Workqueue: events jump_label_update_timeout\n[] RIP: 0010:__jump_label_patch+0x2f6/0x350\n...\n[] Call Trace:\n[]  \u003cTASK\u003e\n[]  arch_jump_label_transform_queue+0x6c/0x110\n[]  __jump_label_update+0xef/0x350\n[]  __static_key_slow_dec_cpuslocked.part.0+0x3c/0x60\n[]  jump_label_update_timeout+0x2c/0x40\n[]  process_one_work+0xe3b/0x1670\n[]  worker_thread+0x587/0xce0\n[]  kthread+0x28a/0x350\n[]  ret_from_fork+0x31/0x70\n[]  ret_from_fork_asm+0x1a/0x30\n[]  \u003c/TASK\u003e\n[] Modules linked in: veth\n[] ---[ end trace 0000000000000000 ]---\n[] RIP: 0010:__jump_label_patch+0x2f6/0x350\n\n[1]: https://netdev-3.bots.linux.dev/vmksft-tcp-ao-dbg/results/696681/5-connect-deny-ipv6/stderr"
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            {
              "url": "https://git.kernel.org/stable/c/14ab4792ee120c022f276a7e4768f4dcb08f0cdd"
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          "title": "net/tcp: Disable TCP-AO static key after RCU grace period",
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        "assignerShortName": "Linux",
        "cveId": "CVE-2024-43887",
        "datePublished": "2024-08-26T10:10:39.383Z",
        "dateReserved": "2024-08-17T09:11:59.288Z",
        "dateUpdated": "2026-05-11T20:31:43.999Z",
        "state": "PUBLISHED"
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    }
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.