fkie_cve-2024-26676
Vulnerability from fkie_nvd
Published
2024-04-02 07:15
Modified
2025-05-07 20:15
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: af_unix: Call kfree_skb() for dead unix_(sk)->oob_skb in GC. syzbot reported a warning [0] in __unix_gc() with a repro, which creates a socketpair and sends one socket's fd to itself using the peer. socketpair(AF_UNIX, SOCK_STREAM, 0, [3, 4]) = 0 sendmsg(4, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\360", iov_len=1}], msg_iovlen=1, msg_control=[{cmsg_len=20, cmsg_level=SOL_SOCKET, cmsg_type=SCM_RIGHTS, cmsg_data=[3]}], msg_controllen=24, msg_flags=0}, MSG_OOB|MSG_PROBE|MSG_DONTWAIT|MSG_ZEROCOPY) = 1 This forms a self-cyclic reference that GC should finally untangle but does not due to lack of MSG_OOB handling, resulting in memory leak. Recently, commit 11498715f266 ("af_unix: Remove io_uring code for GC.") removed io_uring's dead code in GC and revealed the problem. The code was executed at the final stage of GC and unconditionally moved all GC candidates from gc_candidates to gc_inflight_list. That papered over the reported problem by always making the following WARN_ON_ONCE(!list_empty(&gc_candidates)) false. The problem has been there since commit 2aab4b969002 ("af_unix: fix struct pid leaks in OOB support") added full scm support for MSG_OOB while fixing another bug. To fix this problem, we must call kfree_skb() for unix_sk(sk)->oob_skb if the socket still exists in gc_candidates after purging collected skb. Then, we need to set NULL to oob_skb before calling kfree_skb() because it calls last fput() and triggers unix_release_sock(), where we call duplicate kfree_skb(u->oob_skb) if not NULL. Note that the leaked socket remained being linked to a global list, so kmemleak also could not detect it. We need to check /proc/net/protocol to notice the unfreed socket. [0]: WARNING: CPU: 0 PID: 2863 at net/unix/garbage.c:345 __unix_gc+0xc74/0xe80 net/unix/garbage.c:345 Modules linked in: CPU: 0 PID: 2863 Comm: kworker/u4:11 Not tainted 6.8.0-rc1-syzkaller-00583-g1701940b1a02 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Workqueue: events_unbound __unix_gc RIP: 0010:__unix_gc+0xc74/0xe80 net/unix/garbage.c:345 Code: 8b 5c 24 50 e9 86 f8 ff ff e8 f8 e4 22 f8 31 d2 48 c7 c6 30 6a 69 89 4c 89 ef e8 97 ef ff ff e9 80 f9 ff ff e8 dd e4 22 f8 90 <0f> 0b 90 e9 7b fd ff ff 48 89 df e8 5c e7 7c f8 e9 d3 f8 ff ff e8 RSP: 0018:ffffc9000b03fba0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffc9000b03fc10 RCX: ffffffff816c493e RDX: ffff88802c02d940 RSI: ffffffff896982f3 RDI: ffffc9000b03fb30 RBP: ffffc9000b03fce0 R08: 0000000000000001 R09: fffff52001607f66 R10: 0000000000000003 R11: 0000000000000002 R12: dffffc0000000000 R13: ffffc9000b03fc10 R14: ffffc9000b03fc10 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005559c8677a60 CR3: 000000000d57a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> process_one_work+0x889/0x15e0 kernel/workqueue.c:2633 process_scheduled_works kernel/workqueue.c:2706 [inline] worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787 kthread+0x2c6/0x3b0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 </TASK>
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1279f9d9dec2d7462823a18c29ad61359e0a007dPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4fe505c63aa3273135a57597fda761e9aecc7668Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/82ae47c5c3a6b27fdc0f9e83c1499cb439c56140Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b74aa9ce13d02b7fd37c5325b99854f91b9b4276Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e0e09186d8821ad59806115d347ea32efa43ca4bPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/1279f9d9dec2d7462823a18c29ad61359e0a007dPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/4fe505c63aa3273135a57597fda761e9aecc7668Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/82ae47c5c3a6b27fdc0f9e83c1499cb439c56140Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/b74aa9ce13d02b7fd37c5325b99854f91b9b4276Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/e0e09186d8821ad59806115d347ea32efa43ca4bPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.8
linux linux_kernel 6.8
linux linux_kernel 6.8


To clipboard 

{
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          "negate": false,
          "operator": "OR"
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Call kfree_skb() for dead unix_(sk)-\u003eoob_skb in GC.\n\nsyzbot reported a warning [0] in __unix_gc() with a repro, which\ncreates a socketpair and sends one socket\u0027s fd to itself using the\npeer.\n\n  socketpair(AF_UNIX, SOCK_STREAM, 0, [3, 4]) = 0\n  sendmsg(4, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base=\"\\360\", iov_len=1}],\n          msg_iovlen=1, msg_control=[{cmsg_len=20, cmsg_level=SOL_SOCKET,\n                                      cmsg_type=SCM_RIGHTS, cmsg_data=[3]}],\n          msg_controllen=24, msg_flags=0}, MSG_OOB|MSG_PROBE|MSG_DONTWAIT|MSG_ZEROCOPY) = 1\n\nThis forms a self-cyclic reference that GC should finally untangle\nbut does not due to lack of MSG_OOB handling, resulting in memory\nleak.\n\nRecently, commit 11498715f266 (\"af_unix: Remove io_uring code for\nGC.\") removed io_uring\u0027s dead code in GC and revealed the problem.\n\nThe code was executed at the final stage of GC and unconditionally\nmoved all GC candidates from gc_candidates to gc_inflight_list.\nThat papered over the reported problem by always making the following\nWARN_ON_ONCE(!list_empty(\u0026gc_candidates)) false.\n\nThe problem has been there since commit 2aab4b969002 (\"af_unix: fix\nstruct pid leaks in OOB support\") added full scm support for MSG_OOB\nwhile fixing another bug.\n\nTo fix this problem, we must call kfree_skb() for unix_sk(sk)-\u003eoob_skb\nif the socket still exists in gc_candidates after purging collected skb.\n\nThen, we need to set NULL to oob_skb before calling kfree_skb() because\nit calls last fput() and triggers unix_release_sock(), where we call\nduplicate kfree_skb(u-\u003eoob_skb) if not NULL.\n\nNote that the leaked socket remained being linked to a global list, so\nkmemleak also could not detect it.  We need to check /proc/net/protocol\nto notice the unfreed socket.\n\n[0]:\nWARNING: CPU: 0 PID: 2863 at net/unix/garbage.c:345 __unix_gc+0xc74/0xe80 net/unix/garbage.c:345\nModules linked in:\nCPU: 0 PID: 2863 Comm: kworker/u4:11 Not tainted 6.8.0-rc1-syzkaller-00583-g1701940b1a02 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nWorkqueue: events_unbound __unix_gc\nRIP: 0010:__unix_gc+0xc74/0xe80 net/unix/garbage.c:345\nCode: 8b 5c 24 50 e9 86 f8 ff ff e8 f8 e4 22 f8 31 d2 48 c7 c6 30 6a 69 89 4c 89 ef e8 97 ef ff ff e9 80 f9 ff ff e8 dd e4 22 f8 90 \u003c0f\u003e 0b 90 e9 7b fd ff ff 48 89 df e8 5c e7 7c f8 e9 d3 f8 ff ff e8\nRSP: 0018:ffffc9000b03fba0 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffffc9000b03fc10 RCX: ffffffff816c493e\nRDX: ffff88802c02d940 RSI: ffffffff896982f3 RDI: ffffc9000b03fb30\nRBP: ffffc9000b03fce0 R08: 0000000000000001 R09: fffff52001607f66\nR10: 0000000000000003 R11: 0000000000000002 R12: dffffc0000000000\nR13: ffffc9000b03fc10 R14: ffffc9000b03fc10 R15: 0000000000000001\nFS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005559c8677a60 CR3: 000000000d57a000 CR4: 00000000003506f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n process_one_work+0x889/0x15e0 kernel/workqueue.c:2633\n process_scheduled_works kernel/workqueue.c:2706 [inline]\n worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787\n kthread+0x2c6/0x3b0 kernel/kthread.c:388\n ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242\n \u003c/TASK\u003e"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: af_unix: Llame a kfree_skb() para unix_(sk)-\u0026gt;oob_skb muerto en GC. syzbot inform\u00f3 una advertencia [0] en __unix_gc() con una reproducci\u00f3n, que crea un par de sockets y se env\u00eda el fd de un socket a s\u00ed mismo utilizando el par. socketpair(AF_UNIX, SOCK_STREAM, 0, [3, 4]) = 0 sendmsg(4, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base=\"\\360\", iov_len=1}], msg_iovlen=1, msg_control=[{cmsg_len=20, cmsg_level=SOL_SOCKET, cmsg_type=SCM_RIGHTS, cmsg_data=[3]}], msg_controllen=24, msg_flags=0}, MSG_OOB|MSG_PROBE|MSG_DONTWAIT|MSG_ZEROCOPY) = 1 Esto forma una referencia autoc\u00edclica ese GC finalmente deber\u00eda desenredarse, pero no lo hace debido a la falta de manejo de MSG_OOB, lo que resulta en una p\u00e9rdida de memoria. Recientemente, el commit 11498715f266 (\"af_unix: Eliminar el c\u00f3digo io_uring para GC.\") elimin\u00f3 el c\u00f3digo inactivo de io_uring en GC y revel\u00f3 el problema. El c\u00f3digo se ejecut\u00f3 en la etapa final de GC y movi\u00f3 incondicionalmente todos los candidatos de GC de gc_candidates a gc_inflight_list. Eso ocult\u00f3 el problema informado haciendo siempre que lo siguiente WARN_ON_ONCE(!list_empty(\u0026amp;gc_candidates)) fuera falso. El problema ha estado ah\u00ed desde que el commit 2aab4b969002 (\"af_unix: corrige fugas de struct pid en soporte OOB\") agreg\u00f3 soporte completo de scm para MSG_OOB mientras solucionaba otro error. Para solucionar este problema, debemos llamar a kfree_skb() para unix_sk(sk)-\u0026gt;oob_skb si el socket todav\u00eda existe en gc_candidates despu\u00e9s de purgar el skb recopilado. Luego, necesitamos establecer NULL en oob_skb antes de llamar a kfree_skb() porque llama al \u00faltimo fput() y activa unix_release_sock(), donde llamamos al duplicado kfree_skb(u-\u0026gt;oob_skb) si no es NULL. Tenga en cuenta que el socket filtrado segu\u00eda vinculado a una lista global, por lo que kmemleak tampoco pudo detectarlo. Necesitamos verificar /proc/net/protocol para notar el socket no liberado. [0]: ADVERTENCIA: CPU: 0 PID: 2863 en net/unix/garbage.c:345 __unix_gc+0xc74/0xe80 net/unix/garbage.c:345 M\u00f3dulos vinculados en: CPU: 0 PID: 2863 Comm: kworker/ u4:11 No contaminado 6.8.0-rc1-syzkaller-00583-g1701940b1a02 #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 25/01/2024 Cola de trabajo: events_unbound __unix_gc RIP: 0010:__unix_gc+0xc74/0xe80 net/unix/garbage.c:345 C\u00f3digo: 8b 5c 24 50 e9 86 f8 ff ff e8 f8 e4 22 f8 31 d2 48 c7 c6 30 6a 69 89 4c 89 ef e8 97 ef ff ff e9 80 f9 ff ff e8 dd e4 22 f8 90 \u0026lt;0f\u0026gt; 0b 90 e9 7b fd ff ff 48 89 df e8 5c e7 7c f8 e9 d3 f8 ff ff e8 RSP: 0018:ffffc9000b03fba0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff c9000b03fc10 RCX: ffffffff816c493e RDX: ffff88802c02d940 RSI: ffffffff896982f3 RDI: ffffc9000b03fb30 RBP: ffffc9000b03fce0 R08: 0000000000000001 R09: fffff52001607f66 R10: 00000000000000003 R11: 00000000000000002 R12: dffffc 0000000000 R13: ffffc9000b03fc10 R14: ffffc9000b03fc10 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:000 0000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005559c8677a60 CR3: 000000000d57a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 00000000 00000000 DR2: 0000000000000000 DR3: 00000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Seguimiento de llamadas:  Process_one_work+0x889/0x15e0 kernel/workqueue.c :2633 Process_scheduled_works kernel/workqueue.c:2706 [en l\u00ednea] work_thread+0x8b9/0x12a0 kernel/workqueue.c:2787 kthread+0x2c6/0x3b0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process. c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 "
    }
  ],
  "id": "CVE-2024-26676",
  "lastModified": "2025-05-07T20:15:23.713",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2024-04-02T07:15:44.170",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/1279f9d9dec2d7462823a18c29ad61359e0a007d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/4fe505c63aa3273135a57597fda761e9aecc7668"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/82ae47c5c3a6b27fdc0f9e83c1499cb439c56140"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b74aa9ce13d02b7fd37c5325b99854f91b9b4276"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/e0e09186d8821ad59806115d347ea32efa43ca4b"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/1279f9d9dec2d7462823a18c29ad61359e0a007d"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/4fe505c63aa3273135a57597fda761e9aecc7668"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/82ae47c5c3a6b27fdc0f9e83c1499cb439c56140"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b74aa9ce13d02b7fd37c5325b99854f91b9b4276"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/e0e09186d8821ad59806115d347ea32efa43ca4b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-401"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-401"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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