Linux: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2024-50234 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in Linux, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 271d282ecc15d7012e71ca82c89a6c0e13a063dd, 9d89941e51259c2b0b8e9c10c6f1f74200d7444f, d0231f43df473e2f80372d0ca150eb3619932ef9 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 271d282ecc15d7012e71ca82c89a6c0e13a063dd or 9d89941e51259c2b0b8e9c10c6f1f74200d7444f or d0231f43df473e2f80372d0ca150eb3619932ef9 or 8ac22fe1e2b104c37e4fecd97735f64bd6349ebc, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.323 or 5.4.285 or 5.10.229 or 5.15.171, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 271d282ecc15d7012e71ca82c89a6c0e13a063dd; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 9d89941e51259c2b0b8e9c10c6f1f74200d7444f; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, d0231f43df473e2f80372d0ca150eb3619932ef9; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 8ac22fe1e2b104c37e4fecd97735f64bd6349ebc; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 23f9cef17ee315777dbe88d5c11ff6166e4d0699; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, cedf0f1db8d5f3524339c2c6e35a8505b0f1ab73; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 8af8294d369a871cdbcdbb4d13b87d2d6e490a1f; e655b9f03f41c7a84fb74d6619abf844d7f2ab65 up to, but not including, 07c90acb071b9954e1fecb1e4f4f13d12c544b34; and 1 more ranges | 271d282ecc15d7012e71ca82c89a6c0e13a063dd, 9d89941e51259c2b0b8e9c10c6f1f74200d7444f, d0231f43df473e2f80372d0ca150eb3619932ef9, 8ac22fe1e2b104c37e4fecd97735f64bd6349ebc, 23f9cef17ee315777dbe88d5c11ff6166e4d0699, cedf0f1db8d5f3524339c2c6e35a8505b0f1ab73 |
| Linux | Linux Kernel | before 4.19.323; 4.20 up to, but not including, 5.4.285; 5.5 up to, but not including, 5.10.229; 5.11 up to, but not including, 5.15.171; 5.16 up to, but not including, 6.1.116; 6.2 up to, but not including, 6.6.60; 6.7 up to, but not including, 6.11.7; 6.12 | 4.19.323, 5.4.285, 5.10.229, 5.15.171, 6.1.116, 6.6.60 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | NVD |
| CVSS 3.1 | 7.0 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: iwlegacy: Clear stale interrupts before resuming device iwl4965 fails upon resume from hibernation on my laptop. The reason seems to be a stale interrupt which isn't being cleared out before interrupts are enabled. We end up with a race beween the resume trying to bring things back up, and the restart work (queued form the interrupt handler) trying to bring things down. Eventually the whole thing blows up. Fix the problem by clearing out any stale interrupts before interrupts get enabled during resume. Here's a debug log of the indicent: [ 12.042589] ieee80211 phy0: il_isr ISR inta 0x00000080, enabled 0xaa00008b, fh 0x00000000 [ 12.042625] ieee80211 phy0: il4965_irq_tasklet inta 0x00000080, enabled 0x00000000, fh 0x00000000 [ 12.042651] iwl4965 0000:10:00.0: RF_KILL bit toggled to enable radio. [ 12.042653] iwl4965 0000:10:00.0: On demand firmware reload [ 12.042690] ieee80211 phy0: il4965_irq_tasklet End inta 0x00000000, enabled 0xaa00008b, fh 0x00000000, flags 0x00000282 [ 12.052207] ieee80211 phy0: il4965_mac_start enter [ 12.052212] ieee80211 phy0: il_prep_station Add STA to driver ID 31: ff:ff:ff:ff:ff:ff [ 12.052244] ieee80211 phy0: il4965_set_hw_ready hardware ready [ 12.052324] ieee80211 phy0: il_apm_init Init card's basic functions [ 12.052348] ieee80211 phy0: il_apm_init L1 Enabled; Disabling L0S [ 12.055727] ieee80211 phy0: il4965_load_bsm Begin load bsm [ 12.056140] ieee80211 phy0: il4965_verify_bsm Begin verify bsm [ 12.058642] ieee80211 phy0: il4965_verify_bsm BSM bootstrap uCode image OK [ 12.058721] ieee80211 phy0: il4965_load_bsm BSM write complete, poll 1 iterations [ 12.058734] ieee80211 phy0: __il4965_up iwl4965 is coming up [ 12.058737] ieee80211 phy0: il4965_mac_start Start UP work done. [ 12.058757] ieee80211 phy0: __il4965_down iwl4965 is going down [ 12.058761] ieee80211 phy0: il_scan_cancel_timeout Scan cancel timeout [ 12.058762] ieee80211 phy0: il_do_scan_abort Not performing scan to abort [ 12.058765] ieee80211 phy0: il_clear_ucode_stations Clearing ucode stations in driver [ 12.058767] ieee80211 phy0: il_clear_ucode_stations No active stations found to be cleared [ 12.058819] ieee80211 phy0: _il_apm_stop Stop card, put in low power state [ 12.058827] ieee80211 phy0: _il_apm_stop_master stop master [ 12.058864] ieee80211 phy0: il4965_clear_free_frames 0 frames on pre-allocated heap on clear. [ 12.058869] ieee80211 phy0: Hardware restart was requested [ 16.132299] iwl4965 0000:10:00.0: START_ALIVE timeout after 4000ms. [ 16.132303] ------------[ cut here ]------------ [ 16.132304] Hardware became unavailable upon resume. This could be a software issue prior to suspend or a hardware issue. [ 16.132338] WARNING: CPU: 0 PID: 181 at net/mac80211/util.c:1826 ieee80211_reconfig+0x8f/0x14b0 [mac80211] [ 16.132390] Modules linked in: ctr ccm sch_fq_codel xt_tcpudp xt_multiport xt_state iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv4 ip_tables x_tables binfmt_misc joydev mousedev btusb btrtl btintel btbcm bluetooth ecdh_generic ecc iTCO_wdt i2c_dev iwl4965 iwlegacy coretemp snd_hda_codec_analog pcspkr psmouse mac80211 snd_hda_codec_generic libarc4 sdhci_pci cqhci sha256_generic sdhci libsha256 firewire_ohci snd_hda_intel snd_intel_dspcfg mmc_core snd_hda_codec snd_hwdep firewire_core led_class iosf_mbi snd_hda_core uhci_hcd lpc_ich crc_itu_t cfg80211 ehci_pci ehci_hcd snd_pcm usbcore mfd_core rfkill snd_timer snd usb_common soundcore video parport_pc parport intel_agp wmi intel_gtt backlight e1000e agpgart evdev [ 16.132456] CPU: 0 UID: 0 PID: 181 Comm: kworker/u8:6 Not tainted 6.11.0-cl+ #143 [ 16.132460] Hardware name: Hewlett-Packard HP Compaq 6910p/30BE, BIOS 68MCU Ver. F.19 07/06/2010 [ 16.132463] Workqueue: async async_run_entry_fn [ 16.132469] RIP: 0010:ieee80211_reconfig+0x8f/0x14b0 [mac80211] [ 16.132501] Code: da 02 00 0 ---truncated---
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
How developers prevent this class of flaw
- The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
- When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
- Limit the interleaving of operations on files from multiple processes.
More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/07c90acb071b9954e1fecb1e4f4f13d12c544b34
- git.kernel.org/stable/c/23f9cef17ee315777dbe88d5c11ff6166e4d0699
- git.kernel.org/stable/c/271d282ecc15d7012e71ca82c89a6c0e13a063dd
- git.kernel.org/stable/c/8ac22fe1e2b104c37e4fecd97735f64bd6349ebc
- git.kernel.org/stable/c/8af8294d369a871cdbcdbb4d13b87d2d6e490a1f
- git.kernel.org/stable/c/9d89941e51259c2b0b8e9c10c6f1f74200d7444f
- git.kernel.org/stable/c/cedf0f1db8d5f3524339c2c6e35a8505b0f1ab73
- git.kernel.org/stable/c/d0231f43df473e2f80372d0ca150eb3619932ef9
Other references
Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities
- 7.0 High severity
- 7.5 High severity
- 8.3 High severity
- 9.8 Critical severity
- 7.0 High severity
- 7.0 High severity
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