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GHSA-WV8M-2PXF-RH83

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31
VLAI
Details

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

iommu/iommufd: Fix NULL pointer deref in iommufd_ioas_change_process when racing with iopt_map_file_pages

iommufd_ioas_change_process() iterates every IOAS area while only holding every IOAS iova_rwsem, so it assumes every area has a non-NULL pages pointer. That assumption can be false when it runs concurrently with iopt_map_file_pages().

iopt_map_pages() executes in two phases. It first creates the area and inserts it into the interval tree under iova_rwsem, with area->pages still NULL. It then drops iova_rwsem and later fills area->pages under domains_rwsem. This leaves a window between area creation and area->pages fill where a concurrent iommufd_ioas_change_process() can observe the area and dereference a NULL area->pages pointer, leading to a NULL pointer dereference:

BUG: kernel NULL pointer dereference, address: 00000000000000c0

PF: supervisor read access in kernel mode

PF: error_code(0x0000) - not-present page

PGD 4b655067 P4D 4b655067 PUD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 11841 Comm: syz.1.628 Not tainted 7.1.0 #3 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:iommufd_ioas_change_process+0x419/0xd50 drivers/iommu/iommufd/ioas.c:538 Code: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd <8b> ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74 RSP: 0018:ffffc90015c17d28 EFLAGS: 00010246 RAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000 RDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0 RBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000 R10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008 R13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f4aea3f66c0(0000) GS:ffff8880b1fa1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 000000004b75c000 CR4: 0000000000350ef0 Call Trace: iommufd_fops_ioctl+0x287/0x400 drivers/iommu/iommufd/main.c:533 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x120/0x170 fs/ioctl.c:583 x64_sys_call+0x1092/0x1fb0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10a/0x680 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4aec1a82bd Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4aea3f6018 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4aec436090 RCX: 00007f4aec1a82bd RDX: 0000200000000180 RSI: 0000000000003b92 RDI: 0000000000000003 RBP: 00007f4aec250295 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4aec436128 R14: 00007f4aec436090 R15: 00007ffd04ef23e0 Modules linked in: CR2: 00000000000000c0 ---[ end trace 0000000000000000 ]--- RIP: 0010:iommufd_ioas_change_process+0x419/0xd50 drivers/iommu/iommufd/ioas.c:538 Code: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd <8b> ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74 RSP: 0018:ffffc90015c17d28 EFLAGS: 00010246 RAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000 RDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0 RBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000 R10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008 R13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f4aea3f66c0(000 ---truncated---

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-80817"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:09Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/iommufd: Fix NULL pointer deref in iommufd_ioas_change_process when racing with iopt_map_file_pages\n\niommufd_ioas_change_process() iterates every IOAS area while only\nholding every IOAS iova_rwsem, so it assumes every area has a non-NULL\npages pointer. That assumption can be false when it runs concurrently\nwith iopt_map_file_pages().\n\niopt_map_pages() executes in two phases. It first creates the area and\ninserts it into the interval tree under iova_rwsem, with area-\u003epages\nstill NULL. It then drops iova_rwsem and later fills area-\u003epages\nunder domains_rwsem. This leaves a window between area creation and\narea-\u003epages fill where a concurrent iommufd_ioas_change_process()\ncan observe the area and dereference a NULL area-\u003epages pointer,\nleading to a NULL pointer dereference:\n\nBUG: kernel NULL pointer dereference, address: 00000000000000c0\n#PF: supervisor read access in kernel mode\n#PF: error_code(0x0000) - not-present page\nPGD 4b655067 P4D 4b655067 PUD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 0 UID: 0 PID: 11841 Comm: syz.1.628 Not tainted 7.1.0 #3 PREEMPT(full)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:iommufd_ioas_change_process+0x419/0xd50 drivers/iommu/iommufd/ioas.c:538\nCode: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd \u003c8b\u003e ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74\nRSP: 0018:ffffc90015c17d28 EFLAGS: 00010246\nRAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000\nRDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0\nRBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000\nR10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008\nR13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000\nFS:  00007f4aea3f66c0(0000) GS:ffff8880b1fa1000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00000000000000c0 CR3: 000000004b75c000 CR4: 0000000000350ef0\nCall Trace:\n \u003cTASK\u003e\n iommufd_fops_ioctl+0x287/0x400 drivers/iommu/iommufd/main.c:533\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl fs/ioctl.c:583 [inline]\n __x64_sys_ioctl+0x120/0x170 fs/ioctl.c:583\n x64_sys_call+0x1092/0x1fb0 arch/x86/include/generated/asm/syscalls_64.h:17\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x10a/0x680 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f4aec1a82bd\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007f4aea3f6018 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007f4aec436090 RCX: 00007f4aec1a82bd\nRDX: 0000200000000180 RSI: 0000000000003b92 RDI: 0000000000000003\nRBP: 00007f4aec250295 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007f4aec436128 R14: 00007f4aec436090 R15: 00007ffd04ef23e0\n \u003c/TASK\u003e\nModules linked in:\nCR2: 00000000000000c0\n---[ end trace 0000000000000000 ]---\nRIP: 0010:iommufd_ioas_change_process+0x419/0xd50 drivers/iommu/iommufd/ioas.c:538\nCode: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd \u003c8b\u003e ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74\nRSP: 0018:ffffc90015c17d28 EFLAGS: 00010246\nRAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000\nRDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0\nRBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000\nR10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008\nR13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000\nFS:  00007f4aea3f66c0(000\n---truncated---",
  "id": "GHSA-wv8m-2pxf-rh83",
  "modified": "2026-09-04T18:31:27Z",
  "published": "2026-09-04T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80817"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7596354148c5aa12dfaa17992d1aef1aa2ea831a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d616de490ec0242dcf78f02f1adf7baa035c4d0d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d9635e2507dc8260b9ba9992a4198e84f9340a15"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ffe6d379be20df013e19a4c63dd80bc6b683106d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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