{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-53170",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2024-53170"
  ],
  "published": "2024-12-27T13:53:01Z",
  "summary": "block: fix uaf for flush rq while iterating tags",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix uaf for flush rq while iterating tags\n\nblk_mq_clear_flush_rq_mapping() is not called during scsi probe, by\nchecking blk_queue_init_done(). However, QUEUE_FLAG_INIT_DONE is cleared\nin del_gendisk by commit aec89dc5d421 (\"block: keep q_usage_counter in\natomic mode after del_gendisk\"), hence for disk like scsi, following\nblk_mq_destroy_queue() will not clear flush rq from tags->rqs[] as well,\ncause following uaf that is found by our syzkaller for v6.6:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in blk_mq_find_and_get_req+0x16e/0x1a0 block/blk-mq-tag.c:261\nRead of size 4 at addr ffff88811c969c20 by task kworker/1:2H/224909\n\nCPU: 1 PID: 224909 Comm: kworker/1:2H Not tainted 6.6.0-ga836a5060850 #32\nWorkqueue: kblockd blk_mq_timeout_work\nCall Trace:\n\n__dump_stack lib/dump_stack.c:88 [inline]\ndump_stack_lvl+0x91/0xf0 lib/dump_stack.c:106\nprint_address_description.constprop.0+0x66/0x300 mm/kasan/report.c:364\nprint_report+0x3e/0x70 mm/kasan/report.c:475\nkasan_report+0xb8/0xf0 mm/kasan/report.c:588\nblk_mq_find_and_get_req+0x16e/0x1a0 block/blk-mq-tag.c:261\nbt_iter block/blk-mq-tag.c:288 [inline]\n__sbitmap_for_each_set include/linux/sbitmap.h:295 [inline]\nsbitmap_for_each_set include/linux/sbitmap.h:316 [inline]\nbt_for_each+0x455/0x790 block/blk-mq-tag.c:325\nblk_mq_queue_tag_busy_iter+0x320/0x740 block/blk-mq-tag.c:534\nblk_mq_timeout_work+0x1a3/0x7b0 block/blk-mq.c:1673\nprocess_one_work+0x7c4/0x1450 kernel/workqueue.c:2631\nprocess_scheduled_works kernel/workqueue.c:2704 [inline]\nworker_thread+0x804/0xe40 kernel/workqueue.c:2785\nkthread+0x346/0x450 kernel/kthread.c:388\nret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147\nret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:293\n\nAllocated by task 942:\nkasan_save_stack+0x22/0x50 mm/kasan/common.c:45\nkasan_set_track+0x25/0x30 mm/kasan/common.c:52\n____kasan_kmalloc mm/kasan/common.c:374 [inline]\n__kasan_kmalloc mm/kasan/common.c:383 [inline]\n__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:380\nkasan_kmalloc include/linux/kasan.h:198 [inline]\n__do_kmalloc_node mm/slab_common.c:1007 [inline]\n__kmalloc_node+0x69/0x170 mm/slab_common.c:1014\nkmalloc_node include/linux/slab.h:620 [inline]\nkzalloc_node include/linux/slab.h:732 [inline]\nblk_alloc_flush_queue+0x144/0x2f0 block/blk-flush.c:499\nblk_mq_alloc_hctx+0x601/0x940 block/blk-mq.c:3788\nblk_mq_alloc_and_init_hctx+0x27f/0x330 block/blk-mq.c:4261\nblk_mq_realloc_hw_ctxs+0x488/0x5e0 block/blk-mq.c:4294\nblk_mq_init_allocated_queue+0x188/0x860 block/blk-mq.c:4350\nblk_mq_init_queue_data block/blk-mq.c:4166 [inline]\nblk_mq_init_queue+0x8d/0x100 block/blk-mq.c:4176\nscsi_alloc_sdev+0x843/0xd50 drivers/scsi/scsi_scan.c:335\nscsi_probe_and_add_lun+0x77c/0xde0 drivers/scsi/scsi_scan.c:1189\n__scsi_scan_target+0x1fc/0x5a0 drivers/scsi/scsi_scan.c:1727\nscsi_scan_channel drivers/scsi/scsi_scan.c:1815 [inline]\nscsi_scan_channel+0x14b/0x1e0 drivers/scsi/scsi_scan.c:1791\nscsi_scan_host_selected+0x2fe/0x400 drivers/scsi/scsi_scan.c:1844\nscsi_scan+0x3a0/0x3f0 drivers/scsi/scsi_sysfs.c:151\nstore_scan+0x2a/0x60 drivers/scsi/scsi_sysfs.c:191\ndev_attr_store+0x5c/0x90 drivers/base/core.c:2388\nsysfs_kf_write+0x11c/0x170 fs/sysfs/file.c:136\nkernfs_fop_write_iter+0x3fc/0x610 fs/kernfs/file.c:338\ncall_write_iter include/linux/fs.h:2083 [inline]\nnew_sync_write+0x1b4/0x2d0 fs/read_write.c:493\nvfs_write+0x76c/0xb00 fs/read_write.c:586\nksys_write+0x127/0x250 fs/read_write.c:639\ndo_syscall_x64 arch/x86/entry/common.c:51 [inline]\ndo_syscall_64+0x70/0x120 arch/x86/entry/common.c:81\nentry_SYSCALL_64_after_hwframe+0x78/0xe2\n\nFreed by task 244687:\nkasan_save_stack+0x22/0x50 mm/kasan/common.c:45\nkasan_set_track+0x25/0x30 mm/kasan/common.c:52\nkasan_save_free_info+0x2b/0x50 mm/kasan/generic.c:522\n____kasan_slab_free mm/kasan/common.c:236 [inline]\n__kasan_slab_free+0x12a/0x1b0 mm/kasan/common.c:244\nkasan_slab_free include/linux/kasan.h:164 [in\n---truncated---",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
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            "upstream_version": "6.6.51",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.74"
          },
          "1:6.6.62-1+rpt1": {
            "linux_commit": "dd2394360860d15146c96635796a75b05bb32b61",
            "upstream_version": "6.6.62",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.6.74"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-53170"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1921fe7d2836f8be1d321cf430d17e0d4e05301b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1364a29b71c7837770f1902c49e7a6e234d72c92"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a0e93b9fefafe97d596f9c98701ae6c3b04b3ff6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/61092568f2a9acb0e6e186f03f2e0649a4e86d09"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3802f73bd80766d70f319658f334754164075bc3"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:52:36Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerability is in the block layer's blk-mq tag iteration and is reached through local block device I/O (flush/fsync on a SCSI-backed device) plus device teardown; there is no remote protocol handler involved. Exploitation requires local access to drive I/O and groom the kernel heap on the affected host.\nAC:L - The dangling flush_rq pointer is left in the host-wide tags->rqs[] deterministically after any SCSI LUN teardown, and the attacker can drive both sides of the consuming window by keeping heavy I/O on the remaining LUNs of the same SCSI host (forcing timeout/EH tag iteration) while spraying the freed kmalloc slab. No condition depends on state the attacker cannot influence.\nPR:L - An unprivileged local user can supply every attacker-controlled element \u2014 issuing flushes via fsync on a mounted SCSI disk to plant flush_rq in the shared tag array, driving I/O that forces tag iteration, and spraying the generic kmalloc cache to reclaim the freed request; the teardown itself is a routine event (USB/SAN/virtio-scsi hotplug, path loss) rather than an attacker-only capability.\nUI:N - No victim action such as opening a file or mounting a filesystem is required; the use-after-free fires from kernel worker context (blk_mq_timeout_work, SCSI error handling) as ordinary I/O proceeds.\nS:U - The corrupted memory and the impact both reside in the kernel's own security authority; there is no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The freed struct request lives in a generic kmalloc cache that an unprivileged attacker can reclaim with controlled data, and the tag iterator reads fields (rq->tag, rq->q, rq->mq_hctx, rq->state) from it, allowing the attacker to steer subsequent dereferences into arbitrary kernel memory and disclose its contents.\nI:H - Beyond reading, req_ref_inc_not_zero() performs an atomic increment into the freed object, and blk_mq_put_rq_ref() can invoke flush_end_io() on it, which walks fq->flush_queue lists and calls completion callbacks derived from attacker-groomable memory \u2014 a write and control-flow hijack primitive.\nA:H - The use-after-free reliably produces a KASAN slab-use-after-free/oops in blk_mq_find_and_get_req() from the kblockd worker, and unconstrained follow-on dereferences of the freed request cause kernel panics, taking down the storage stack and the system."
    }
  }
}