CVE-2023-52564

2024-03-0222:15:48

416baaa9-dc9f-4396-8d5f-8c081fb06d67

web.nvd.nist.gov

linux

kernel

vulnerability

cve-2023-52564

resolution

commit

revert

security

nvd

6.2 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.7%

JSON

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

Revert “tty: n_gsm: fix UAF in gsm_cleanup_mux”

This reverts commit 9b9c8195f3f0d74a826077fc1c01b9ee74907239.

The commit above is reverted as it did not solve the original issue.

gsm_cleanup_mux() tries to free up the virtual ttys by calling
gsm_dlci_release() for each available DLCI. There, dlci_put() is called to
decrease the reference counter for the DLCI via tty_port_put() which
finally calls gsm_dlci_free(). This already clears the pointer which is
being checked in gsm_cleanup_mux() before calling gsm_dlci_release().
Therefore, it is not necessary to clear this pointer in gsm_cleanup_mux()
as done in the reverted commit. The commit introduces a null pointer
dereference:
<TASK>
? __die+0x1f/0x70
? page_fault_oops+0x156/0x420
? search_exception_tables+0x37/0x50
? fixup_exception+0x21/0x310
? exc_page_fault+0x69/0x150
? asm_exc_page_fault+0x26/0x30
? tty_port_put+0x19/0xa0
gsmtty_cleanup+0x29/0x80 [n_gsm]
release_one_tty+0x37/0xe0
process_one_work+0x1e6/0x3e0
worker_thread+0x4c/0x3d0
? __pfx_worker_thread+0x10/0x10
kthread+0xe1/0x110
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2f/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>

The actual issue is that nothing guards dlci_put() from being called
multiple times while the tty driver was triggered but did not yet finished
calling gsm_dlci_free().

Affected configurations

Vulners

Node

linuxlinux_kernelRange6.5–5.10.198

linuxlinux_kernelRange5.11.0–5.15.134

linuxlinux_kernelRange5.16.0–6.1.56

linuxlinux_kernelRange6.2.0–6.5.6

linuxlinux_kernelRange6.6.0≥

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/tty/n_gsm.c"
    ],
    "versions": [
      {
        "version": "8fc0eabaa73b",
        "lessThan": "6d5c8862932d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "5138c228311a",
        "lessThan": "a48d2bcd23f2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "9615ca54bc13",
        "lessThan": "c61d0b87a702",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "9b9c8195f3f0",
        "lessThan": "2bff660e0ff3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "9b9c8195f3f0",
        "lessThan": "29346e217b8a",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/tty/n_gsm.c"
    ],
    "versions": [
      {
        "version": "6.5",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.5",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.198",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.134",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.56",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.5.6",
        "lessThanOrEqual": "6.5.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]