fkie_cve-2024-43837
Vulnerability from fkie_nvd
Published
2024-08-17 10:15
Modified
2024-08-22 15:44
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: bpf: Fix null pointer dereference in resolve_prog_type() for BPF_PROG_TYPE_EXT When loading a EXT program without specifying `attr->attach_prog_fd`, the `prog->aux->dst_prog` will be null. At this time, calling resolve_prog_type() anywhere will result in a null pointer dereference. Example stack trace: [ 8.107863] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 [ 8.108262] Mem abort info: [ 8.108384] ESR = 0x0000000096000004 [ 8.108547] EC = 0x25: DABT (current EL), IL = 32 bits [ 8.108722] SET = 0, FnV = 0 [ 8.108827] EA = 0, S1PTW = 0 [ 8.108939] FSC = 0x04: level 0 translation fault [ 8.109102] Data abort info: [ 8.109203] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 8.109399] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 8.109614] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 8.109836] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000101354000 [ 8.110011] [0000000000000004] pgd=0000000000000000, p4d=0000000000000000 [ 8.112624] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 8.112783] Modules linked in: [ 8.113120] CPU: 0 PID: 99 Comm: may_access_dire Not tainted 6.10.0-rc3-next-20240613-dirty #1 [ 8.113230] Hardware name: linux,dummy-virt (DT) [ 8.113390] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 8.113429] pc : may_access_direct_pkt_data+0x24/0xa0 [ 8.113746] lr : add_subprog_and_kfunc+0x634/0x8e8 [ 8.113798] sp : ffff80008283b9f0 [ 8.113813] x29: ffff80008283b9f0 x28: ffff800082795048 x27: 0000000000000001 [ 8.113881] x26: ffff0000c0bb2600 x25: 0000000000000000 x24: 0000000000000000 [ 8.113897] x23: ffff0000c1134000 x22: 000000000001864f x21: ffff0000c1138000 [ 8.113912] x20: 0000000000000001 x19: ffff0000c12b8000 x18: ffffffffffffffff [ 8.113929] x17: 0000000000000000 x16: 0000000000000000 x15: 0720072007200720 [ 8.113944] x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720 [ 8.113958] x11: 0720072007200720 x10: 0000000000f9fca4 x9 : ffff80008021f4e4 [ 8.113991] x8 : 0101010101010101 x7 : 746f72705f6d656d x6 : 000000001e0e0f5f [ 8.114006] x5 : 000000000001864f x4 : ffff0000c12b8000 x3 : 000000000000001c [ 8.114020] x2 : 0000000000000002 x1 : 0000000000000000 x0 : 0000000000000000 [ 8.114126] Call trace: [ 8.114159] may_access_direct_pkt_data+0x24/0xa0 [ 8.114202] bpf_check+0x3bc/0x28c0 [ 8.114214] bpf_prog_load+0x658/0xa58 [ 8.114227] __sys_bpf+0xc50/0x2250 [ 8.114240] __arm64_sys_bpf+0x28/0x40 [ 8.114254] invoke_syscall.constprop.0+0x54/0xf0 [ 8.114273] do_el0_svc+0x4c/0xd8 [ 8.114289] el0_svc+0x3c/0x140 [ 8.114305] el0t_64_sync_handler+0x134/0x150 [ 8.114331] el0t_64_sync+0x168/0x170 [ 8.114477] Code: 7100707f 54000081 f9401c00 f9403800 (b9400403) [ 8.118672] ---[ end trace 0000000000000000 ]--- One way to fix it is by forcing `attach_prog_fd` non-empty when bpf_prog_load(). But this will lead to `libbpf_probe_bpf_prog_type` API broken which use verifier log to probe prog type and will log nothing if we reject invalid EXT prog before bpf_check(). Another way is by adding null check in resolve_prog_type(). The issue was introduced by commit 4a9c7bbe2ed4 ("bpf: Resolve to prog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT") which wanted to correct type resolution for BPF_PROG_TYPE_TRACING programs. Before that, the type resolution of BPF_PROG_TYPE_EXT prog actually follows the logic below: prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type; It implies that when EXT program is not yet attached to `dst_prog`, the prog type should be EXT itself. This code worked fine in the past. So just keep using it. Fix this by returning `prog->type` for BPF_PROG_TYPE_EXT if `dst_prog` is not present in resolve_prog_type().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d40fd516aeae6779e3c84c6b96700ca76285847Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b29a880bb145e1f1c1df5ab88ed26b1495ff9f09Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f7866c35873377313ff94398f17d425b28b71de1Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *


To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "ADED9C16-75E2-47CC-A756-30929EBBF848",
              "versionEndExcluding": "6.1.103",
              "versionStartIncluding": "5.18",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CC912330-6B41-4C6B-99AF-F3857FBACB6A",
              "versionEndExcluding": "6.6.44",
              "versionStartIncluding": "6.2",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "92D388F2-1EAF-4CFA-AC06-5B26D762EA7D",
              "versionEndExcluding": "6.10.3",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix null pointer dereference in resolve_prog_type() for BPF_PROG_TYPE_EXT\n\nWhen loading a EXT program without specifying `attr-\u003eattach_prog_fd`,\nthe `prog-\u003eaux-\u003edst_prog` will be null. At this time, calling\nresolve_prog_type() anywhere will result in a null pointer dereference.\n\nExample stack trace:\n\n[    8.107863] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004\n[    8.108262] Mem abort info:\n[    8.108384]   ESR = 0x0000000096000004\n[    8.108547]   EC = 0x25: DABT (current EL), IL = 32 bits\n[    8.108722]   SET = 0, FnV = 0\n[    8.108827]   EA = 0, S1PTW = 0\n[    8.108939]   FSC = 0x04: level 0 translation fault\n[    8.109102] Data abort info:\n[    8.109203]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000\n[    8.109399]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n[    8.109614]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[    8.109836] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000101354000\n[    8.110011] [0000000000000004] pgd=0000000000000000, p4d=0000000000000000\n[    8.112624] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP\n[    8.112783] Modules linked in:\n[    8.113120] CPU: 0 PID: 99 Comm: may_access_dire Not tainted 6.10.0-rc3-next-20240613-dirty #1\n[    8.113230] Hardware name: linux,dummy-virt (DT)\n[    8.113390] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[    8.113429] pc : may_access_direct_pkt_data+0x24/0xa0\n[    8.113746] lr : add_subprog_and_kfunc+0x634/0x8e8\n[    8.113798] sp : ffff80008283b9f0\n[    8.113813] x29: ffff80008283b9f0 x28: ffff800082795048 x27: 0000000000000001\n[    8.113881] x26: ffff0000c0bb2600 x25: 0000000000000000 x24: 0000000000000000\n[    8.113897] x23: ffff0000c1134000 x22: 000000000001864f x21: ffff0000c1138000\n[    8.113912] x20: 0000000000000001 x19: ffff0000c12b8000 x18: ffffffffffffffff\n[    8.113929] x17: 0000000000000000 x16: 0000000000000000 x15: 0720072007200720\n[    8.113944] x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720\n[    8.113958] x11: 0720072007200720 x10: 0000000000f9fca4 x9 : ffff80008021f4e4\n[    8.113991] x8 : 0101010101010101 x7 : 746f72705f6d656d x6 : 000000001e0e0f5f\n[    8.114006] x5 : 000000000001864f x4 : ffff0000c12b8000 x3 : 000000000000001c\n[    8.114020] x2 : 0000000000000002 x1 : 0000000000000000 x0 : 0000000000000000\n[    8.114126] Call trace:\n[    8.114159]  may_access_direct_pkt_data+0x24/0xa0\n[    8.114202]  bpf_check+0x3bc/0x28c0\n[    8.114214]  bpf_prog_load+0x658/0xa58\n[    8.114227]  __sys_bpf+0xc50/0x2250\n[    8.114240]  __arm64_sys_bpf+0x28/0x40\n[    8.114254]  invoke_syscall.constprop.0+0x54/0xf0\n[    8.114273]  do_el0_svc+0x4c/0xd8\n[    8.114289]  el0_svc+0x3c/0x140\n[    8.114305]  el0t_64_sync_handler+0x134/0x150\n[    8.114331]  el0t_64_sync+0x168/0x170\n[    8.114477] Code: 7100707f 54000081 f9401c00 f9403800 (b9400403)\n[    8.118672] ---[ end trace 0000000000000000 ]---\n\nOne way to fix it is by forcing `attach_prog_fd` non-empty when\nbpf_prog_load(). But this will lead to `libbpf_probe_bpf_prog_type`\nAPI broken which use verifier log to probe prog type and will log\nnothing if we reject invalid EXT prog before bpf_check().\n\nAnother way is by adding null check in resolve_prog_type().\n\nThe issue was introduced by commit 4a9c7bbe2ed4 (\"bpf: Resolve to\nprog-\u003eaux-\u003edst_prog-\u003etype only for BPF_PROG_TYPE_EXT\") which wanted\nto correct type resolution for BPF_PROG_TYPE_TRACING programs. Before\nthat, the type resolution of BPF_PROG_TYPE_EXT prog actually follows\nthe logic below:\n\n  prog-\u003eaux-\u003edst_prog ? prog-\u003eaux-\u003edst_prog-\u003etype : prog-\u003etype;\n\nIt implies that when EXT program is not yet attached to `dst_prog`,\nthe prog type should be EXT itself. This code worked fine in the past.\nSo just keep using it.\n\nFix this by returning `prog-\u003etype` for BPF_PROG_TYPE_EXT if `dst_prog`\nis not present in resolve_prog_type()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Se corrigi\u00f3 la desreferencia del puntero nulo en resolve_prog_type() para BPF_PROG_TYPE_EXT Al cargar un programa EXT sin especificar `attr-\u0026gt;attach_prog_fd`, el `prog-\u0026gt;aux-\u0026gt;dst_prog` ser\u00e1 nulo. En este momento, llamar a resolve_prog_type() en cualquier lugar dar\u00e1 como resultado una desreferencia del puntero nulo. Ejemplo de seguimiento de pila: [8.107863] No se puede manejar la desreferencia del puntero NULL del kernel en la direcci\u00f3n virtual 0000000000000004 [8.108262] Informaci\u00f3n de cancelaci\u00f3n de memoria: [8.108384] ESR = 0x0000000096000004 [8.108547] EC = 0x25: DABT (EL actual), IL = 32 bits [8.108722 ] SET = 0, FnV = 0 [8.108827] EA = 0, S1PTW = 0 [8.108939] FSC = 0x04: error de traducci\u00f3n de nivel 0 [8.109102] Informaci\u00f3n de cancelaci\u00f3n de datos: [8.109203] ISV = 0, ISS = 0x00000004, ISS2 = 00 [ 8.109399] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 8.109614] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 8.109836] tabla de p\u00e1ginas de usuario: p\u00e1ginas de 4k, VA de 48 bits, pgdp=0000000101354000 [8.110011] [00000000000000004] pgd=0000000000000000, p4d=0000000000000000 [8.112624] Error interno: Vaya: 0000000096000 004 [#1] PREEMPT SMP [8.112783] M\u00f3dulos vinculados en: [8.113120] CPU: 0 PID: 99 Comm: may_access_dire No contaminado 6.10.0-rc3-next-20240613-dirty #1 [8.113230] Nombre de hardware: linux,dummy-virt (DT) [8.113390] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE= --) [8.113429] pc: may_access_direct_pkt_data+0x24/0xa0 [8.113746] lr: add_subprog_and_kfunc+0x634/0x8e8 [8.113798] sp: ffff80008283b9f0 [8.113813] x29: 83b9f0 x28: ffff800082795048 x27: 00000000000000001 [ 8.113881] x26: ffff0000c0bb2600 x25: 0000000000000000 x24: 0000000000000000 [8.113897] x23: ffff0000c1134000 x22: 000000000001864f x21: ffff0000c1138000 [8.113912] x20: 0000000000000001 x19: ffff0000c12b8000 x18: ffffffffffffffff [ 8.113929] x17: 0000000000000000 x16: 00000000000000000 x15: 0720072007200720 [ 8.113944] x14: 20072007200720 x13: 0720072007200720 x12: 0720072007200720 [8.113958] x11: 0720072007200720 x10: 0000000000f9fca4 x9: ffff80008021f4e4 [8.113991] x8: 0101010101010101 x7: 46f72705f6d656d x6: 000000001e0e0f5f [8.114006] x5: 000000000001864f x4: ffff0000c12b8000 x3: 000000000000001c [8.114020] x2: 00000000002 x1: 0000000000000000 x0: 0000000000000000 [ 8.114126] Seguimiento de llamadas: [8.114159] may_access_direct_pkt_data+0x24/0xa0 [8.114202] bpf_check+0x3bc/0x28c0 [8.114214] bpf_prog_load+0x658/0xa58 [8.114227] xc50/0x2250 [8.114240] __arm64_sys_bpf+0x28/0x40 [8.114254] invoke_syscall. constprop.0+0x54/0xf0 [8.114273] do_el0_svc+0x4c/0xd8 [8.114289] el0_svc+0x3c/0x140 [8.114305] el0t_64_sync_handler+0x134/0x150 [8.114331] _sync+0x168/0x170 [8.114477] C\u00f3digo: 7100707f 54000081 f9401c00 f9403800 (b9400403 ) [8.118672] ---[ end trace 0000000000000000 ]--- Una forma de solucionarlo es forzando que `attach_prog_fd` no est\u00e9 vac\u00edo cuando bpf_prog_load(). Pero esto provocar\u00e1 que se rompa la API `libbpf_probe_bpf_prog_type`, que utiliza el registro del verificador para sondear el tipo de programa y no registrar\u00e1 nada si rechazamos el programa EXT no v\u00e1lido antes de bpf_check(). Otra forma es agregando una verificaci\u00f3n nula en resolve_prog_type(). El problema fue introducido por el commit 4a9c7bbe2ed4 (\"bpf: Resolve to prog-\u0026gt;aux-\u0026gt;dst_prog-\u0026gt;type only for BPF_PROG_TYPE_EXT\") que quer\u00eda corregir la resoluci\u00f3n de tipos para los programas BPF_PROG_TYPE_TRACING. Antes de eso, la resoluci\u00f3n de tipo del programa BPF_PROG_TYPE_EXT en realidad sigue la siguiente l\u00f3gica: prog-\u0026gt;aux-\u0026gt;dst_prog ? prog-\u0026gt;aux-\u0026gt;dst_prog-\u0026gt;tipo : prog-\u0026gt;tipo; Implica que cuando el programa EXT a\u00fan no est\u00e1 adjunto a `dst_prog`, el tipo de programa debe ser EXT. Este c\u00f3digo funcion\u00f3 bien en el pasado. As\u00ed que sigue us\u00e1ndolo. Solucione este problema devolviendo `prog-\u0026gt;type` para BPF_PROG_TYPE_EXT si `dst_prog` no est\u00e1 presente en resolve_prog_type()."
    }
  ],
  "id": "CVE-2024-43837",
  "lastModified": "2024-08-22T15:44:03.417",
  "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": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-08-17T10:15:09.320",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/9d40fd516aeae6779e3c84c6b96700ca76285847"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b29a880bb145e1f1c1df5ab88ed26b1495ff9f09"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/f7866c35873377313ff94398f17d425b28b71de1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/fcac5feb06f31ee4c88bca9bf98d8bc3ca7d2615"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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