ghsa-2c59-vh4j-7xh2
Vulnerability from github
Published
2025-10-21 12:31
Modified
2025-10-21 12:31
Details

In the Linux kernel, the following vulnerability has been resolved:

bpf, arm64: Clear prog->jited_len along prog->jited

syzbot reported an illegal copy_to_user() attempt from bpf_prog_get_info_by_fd() [1]

There was no repro yet on this bug, but I think that commit 0aef499f3172 ("mm/usercopy: Detect vmalloc overruns") is exposing a prior bug in bpf arm64.

bpf_prog_get_info_by_fd() looks at prog->jited_len to determine if the JIT image can be copied out to user space.

My theory is that syzbot managed to get a prog where prog->jited_len has been set to 43, while prog->bpf_func has ben cleared.

It is not clear why copy_to_user(uinsns, NULL, ulen) is triggering this particular warning.

I thought find_vma_area(NULL) would not find a vm_struct. As we do not hold vmap_area_lock spinlock, it might be possible that the found vm_struct was garbage.

[1] usercopy: Kernel memory exposure attempt detected from vmalloc (offset 792633534417210172, size 43)! kernel BUG at mm/usercopy.c:101! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 25002 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-10139-g8291eaafed36 #0 Hardware name: linux,dummy-virt (DT) pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : usercopy_abort+0x90/0x94 mm/usercopy.c:101 lr : usercopy_abort+0x90/0x94 mm/usercopy.c:89 sp : ffff80000b773a20 x29: ffff80000b773a30 x28: faff80000b745000 x27: ffff80000b773b48 x26: 0000000000000000 x25: 000000000000002b x24: 0000000000000000 x23: 00000000000000e0 x22: ffff80000b75db67 x21: 0000000000000001 x20: 000000000000002b x19: ffff80000b75db3c x18: 00000000fffffffd x17: 2820636f6c6c616d x16: 76206d6f72662064 x15: 6574636574656420 x14: 74706d6574746120 x13: 2129333420657a69 x12: 73202c3237313031 x11: 3237313434333533 x10: 3336323937207465 x9 : 657275736f707865 x8 : ffff80000a30c550 x7 : ffff80000b773830 x6 : ffff80000b773830 x5 : 0000000000000000 x4 : ffff00007fbbaa10 x3 : 0000000000000000 x2 : 0000000000000000 x1 : f7ff000028fc0000 x0 : 0000000000000064 Call trace: usercopy_abort+0x90/0x94 mm/usercopy.c:89 check_heap_object mm/usercopy.c:186 [inline] __check_object_size mm/usercopy.c:252 [inline] __check_object_size+0x198/0x36c mm/usercopy.c:214 check_object_size include/linux/thread_info.h:199 [inline] check_copy_size include/linux/thread_info.h:235 [inline] copy_to_user include/linux/uaccess.h:159 [inline] bpf_prog_get_info_by_fd.isra.0+0xf14/0xfdc kernel/bpf/syscall.c:3993 bpf_obj_get_info_by_fd+0x12c/0x510 kernel/bpf/syscall.c:4253 __sys_bpf+0x900/0x2150 kernel/bpf/syscall.c:4956 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline] __se_sys_bpf kernel/bpf/syscall.c:5019 [inline] __arm64_sys_bpf+0x28/0x40 kernel/bpf/syscall.c:5019 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142 do_el0_svc+0xa0/0xc0 arch/arm64/kernel/syscall.c:206 el0_svc+0x44/0xb0 arch/arm64/kernel/entry-common.c:624 el0t_64_sync_handler+0x1ac/0x1b0 arch/arm64/kernel/entry-common.c:642 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581 Code: aa0003e3 d00038c0 91248000 97fff65f (d4210000)

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2022-49341"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:10Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Clear prog-\u003ejited_len along prog-\u003ejited\n\nsyzbot reported an illegal copy_to_user() attempt\nfrom bpf_prog_get_info_by_fd() [1]\n\nThere was no repro yet on this bug, but I think\nthat commit 0aef499f3172 (\"mm/usercopy: Detect vmalloc overruns\")\nis exposing a prior bug in bpf arm64.\n\nbpf_prog_get_info_by_fd() looks at prog-\u003ejited_len\nto determine if the JIT image can be copied out to user space.\n\nMy theory is that syzbot managed to get a prog where prog-\u003ejited_len\nhas been set to 43, while prog-\u003ebpf_func has ben cleared.\n\nIt is not clear why copy_to_user(uinsns, NULL, ulen) is triggering\nthis particular warning.\n\nI thought find_vma_area(NULL) would not find a vm_struct.\nAs we do not hold vmap_area_lock spinlock, it might be possible\nthat the found vm_struct was garbage.\n\n[1]\nusercopy: Kernel memory exposure attempt detected from vmalloc (offset 792633534417210172, size 43)!\nkernel BUG at mm/usercopy.c:101!\nInternal error: Oops - BUG: 0 [#1] PREEMPT SMP\nModules linked in:\nCPU: 0 PID: 25002 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-10139-g8291eaafed36 #0\nHardware name: linux,dummy-virt (DT)\npstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : usercopy_abort+0x90/0x94 mm/usercopy.c:101\nlr : usercopy_abort+0x90/0x94 mm/usercopy.c:89\nsp : ffff80000b773a20\nx29: ffff80000b773a30 x28: faff80000b745000 x27: ffff80000b773b48\nx26: 0000000000000000 x25: 000000000000002b x24: 0000000000000000\nx23: 00000000000000e0 x22: ffff80000b75db67 x21: 0000000000000001\nx20: 000000000000002b x19: ffff80000b75db3c x18: 00000000fffffffd\nx17: 2820636f6c6c616d x16: 76206d6f72662064 x15: 6574636574656420\nx14: 74706d6574746120 x13: 2129333420657a69 x12: 73202c3237313031\nx11: 3237313434333533 x10: 3336323937207465 x9 : 657275736f707865\nx8 : ffff80000a30c550 x7 : ffff80000b773830 x6 : ffff80000b773830\nx5 : 0000000000000000 x4 : ffff00007fbbaa10 x3 : 0000000000000000\nx2 : 0000000000000000 x1 : f7ff000028fc0000 x0 : 0000000000000064\nCall trace:\n usercopy_abort+0x90/0x94 mm/usercopy.c:89\n check_heap_object mm/usercopy.c:186 [inline]\n __check_object_size mm/usercopy.c:252 [inline]\n __check_object_size+0x198/0x36c mm/usercopy.c:214\n check_object_size include/linux/thread_info.h:199 [inline]\n check_copy_size include/linux/thread_info.h:235 [inline]\n copy_to_user include/linux/uaccess.h:159 [inline]\n bpf_prog_get_info_by_fd.isra.0+0xf14/0xfdc kernel/bpf/syscall.c:3993\n bpf_obj_get_info_by_fd+0x12c/0x510 kernel/bpf/syscall.c:4253\n __sys_bpf+0x900/0x2150 kernel/bpf/syscall.c:4956\n __do_sys_bpf kernel/bpf/syscall.c:5021 [inline]\n __se_sys_bpf kernel/bpf/syscall.c:5019 [inline]\n __arm64_sys_bpf+0x28/0x40 kernel/bpf/syscall.c:5019\n __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]\n invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52\n el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142\n do_el0_svc+0xa0/0xc0 arch/arm64/kernel/syscall.c:206\n el0_svc+0x44/0xb0 arch/arm64/kernel/entry-common.c:624\n el0t_64_sync_handler+0x1ac/0x1b0 arch/arm64/kernel/entry-common.c:642\n el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581\nCode: aa0003e3 d00038c0 91248000 97fff65f (d4210000)",
  "id": "GHSA-2c59-vh4j-7xh2",
  "modified": "2025-10-21T12:31:25Z",
  "published": "2025-10-21T12:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49341"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0cf7aaff290cdc4d7cee683d4a18138b0dacac48"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/10f3b29c65bb2fe0d47c2945cd0b4087be1c5218"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f4d5e727aeaa610688d46c9f101f78b7f712583"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/41f7c4f85d402043687e863627a1a84fa867c62d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5c25a3040bc0486c41a7b63a1fb0de7cdb846ad7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aaf61a312af63e1cfe2264c4c5b8cd4ea3626025"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e412b3d178ea4bf746f6b8ee086761613704c6be"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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