ghsa-cqc3-8mfm-84p4
Vulnerability from github
Published
2024-07-16 15:30
Modified
2024-07-23 15:31
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

vhost: fix hung thread due to erroneous iotlb entries

In vhost_iotlb_add_range_ctx(), range size can overflow to 0 when start is 0 and last is ULONG_MAX. One instance where it can happen is when userspace sends an IOTLB message with iova=size=uaddr=0 (vhost_process_iotlb_msg). So, an entry with size = 0, start = 0, last = ULONG_MAX ends up in the iotlb. Next time a packet is sent, iotlb_access_ok() loops indefinitely due to that erroneous entry.

Call Trace:
 <TASK>
 iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340
 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366
 vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104
 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Reported by syzbot at: https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87

To fix this, do two things:

  1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map a range with size 0.
  2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX] by splitting it into two entries.
Show details on source website

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{
   affected: [],
   aliases: [
      "CVE-2022-48862",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-835",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-07-16T13:15:13Z",
      severity: "MODERATE",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost: fix hung thread due to erroneous iotlb entries\n\nIn vhost_iotlb_add_range_ctx(), range size can overflow to 0 when\nstart is 0 and last is ULONG_MAX. One instance where it can happen\nis when userspace sends an IOTLB message with iova=size=uaddr=0\n(vhost_process_iotlb_msg). So, an entry with size = 0, start = 0,\nlast = ULONG_MAX ends up in the iotlb. Next time a packet is sent,\niotlb_access_ok() loops indefinitely due to that erroneous entry.\n\n\tCall Trace:\n\t <TASK>\n\t iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340\n\t vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366\n\t vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104\n\t vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372\n\t kthread+0x2e9/0x3a0 kernel/kthread.c:377\n\t ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295\n\t </TASK>\n\nReported by syzbot at:\n\thttps://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87\n\nTo fix this, do two things:\n\n1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map\n   a range with size 0.\n2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX]\n   by splitting it into two entries.",
   id: "GHSA-cqc3-8mfm-84p4",
   modified: "2024-07-23T15:31:08Z",
   published: "2024-07-16T15:30:50Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2022-48862",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/d9a747e6b6561280bf1791bb24c5e9e082193dad",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/e2ae38cf3d91837a493cb2093c87700ff3cbe667",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/f8d88e86e90ea1002226d7ac2430152bfea003d1",
      },
   ],
   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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