CVE-2024-26690

2024-04-0315:15:52

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

web.nvd.nist.gov

linux kernel

vulnerability

net

stmmac

64-bit statistics

mutual exclusion

seqcount update

stmmac_xmit()

stmmac_napi_poll_tx()

tx queue lock

napi poll

interrupt context

per-cpu struct

stmmac_pcpu_stats

6.6 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.7%

JSON

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

net: stmmac: protect updates of 64-bit statistics counters

As explained by a comment in <linux/u64_stats_sync.h>, write side of struct
u64_stats_sync must ensure mutual exclusion, or one seqcount update could
be lost on 32-bit platforms, thus blocking readers forever. Such lockups
have been observed in real world after stmmac_xmit() on one CPU raced with
stmmac_napi_poll_tx() on another CPU.

To fix the issue without introducing a new lock, split the statics into
three parts:

fields updated only under the tx queue lock,
fields updated only during NAPI poll,
fields updated only from interrupt context,

Updates to fields in the first two groups are already serialized through
other locks. It is sufficient to split the existing struct u64_stats_sync
so that each group has its own.

Note that tx_set_ic_bit is updated from both contexts. Split this counter
so that each context gets its own, and calculate their sum to get the total
value in stmmac_get_ethtool_stats().

For the third group, multiple interrupts may be processed by different CPUs
at the same time, but interrupts on the same CPU will not nest. Move fields
from this group to a newly created per-cpu struct stmmac_pcpu_stats.

Affected configurations

Vulners

Node

linuxlinux_kernelRange6.6–6.6.18

linuxlinux_kernelRange6.7.0–6.7.6

linuxlinux_kernelRange6.8.0≥

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:*:*:*:*:*:*:*:*

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::::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/net/ethernet/stmicro/stmmac/common.h",
      "drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c",
      "drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c",
      "drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c",
      "drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c",
      "drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c",
      "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
    ],
    "versions": [
      {
        "version": "133466c3bbe1",
        "lessThan": "9680b2ab54ba",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "133466c3bbe1",
        "lessThan": "e6af0f082a4b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "133466c3bbe1",
        "lessThan": "38cc3c6dcc09",
        "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/net/ethernet/stmicro/stmmac/common.h",
      "drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c",
      "drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c",
      "drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c",
      "drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c",
      "drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c",
      "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
    ],
    "versions": [
      {
        "version": "6.6",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.6",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.18",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.7.6",
        "lessThanOrEqual": "6.7.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]