CVE-2021-47633

Description

In the Linux kernel, the following vulnerability has been resolved: ath5k: fix OOB in ath5k_eeprom_read_pcal_info_5111 The bug was found during fuzzing. Stacktrace locates it in ath5k_eeprom_convert_pcal_info_5111. When none of the curve is selected in the loop, idx can go up to AR5K_EEPROM_N_PD_CURVES. The line makes pd out of bound. pd = &chinfo[pier].pd_curves[idx]; There are many OOB writes using pd later in the code. So I added a sanity check for idx. Checks for other loops involving AR5K_EEPROM_N_PD_CURVES are not needed as the loop index is not used outside the loops. The patch is NOT tested with real device. The following is the fuzzing report BUG: KASAN: slab-out-of-bounds in ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] Write of size 1 at addr ffff8880174a4d60 by task modprobe/214 CPU: 0 PID: 214 Comm: modprobe Not tainted 5.6.0 #1 Call Trace: dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] __kasan_report.cold+0x37/0x7c ? ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] kasan_report+0xe/0x20 ath5k_eeprom_read_pcal_info_5111+0x126a/0x1390 [ath5k] ? apic_timer_interrupt+0xa/0x20 ? ath5k_eeprom_init_11a_pcal_freq+0xbc0/0xbc0 [ath5k] ? ath5k_pci_eeprom_read+0x228/0x3c0 [ath5k] ath5k_eeprom_init+0x2513/0x6290 [ath5k] ? ath5k_eeprom_init_11a_pcal_freq+0xbc0/0xbc0 [ath5k] ? usleep_range+0xb8/0x100 ? apic_timer_interrupt+0xa/0x20 ? ath5k_eeprom_read_pcal_info_2413+0x2f20/0x2f20 [ath5k] ath5k_hw_init+0xb60/0x1970 [ath5k] ath5k_init_ah+0x6fe/0x2530 [ath5k] ? kasprintf+0xa6/0xe0 ? ath5k_stop+0x140/0x140 [ath5k] ? _dev_notice+0xf6/0xf6 ? apic_timer_interrupt+0xa/0x20 ath5k_pci_probe.cold+0x29a/0x3d6 [ath5k] ? ath5k_pci_eeprom_read+0x3c0/0x3c0 [ath5k] ? mutex_lock+0x89/0xd0 ? ath5k_pci_eeprom_read+0x3c0/0x3c0 [ath5k] local_pci_probe+0xd3/0x160 pci_device_probe+0x23f/0x3e0 ? pci_device_remove+0x280/0x280 ? pci_device_remove+0x280/0x280 really_probe+0x209/0x5d0

Gravité et risque d'exploitation

CVE-2021-47633 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.26 %, ce qui la place devant 17.1 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=5.17.*, 5.18, <25efc5d03455c3839249bc77fce5e29ecb54677e, 5.15.34, 0, <ed3dfdaa8b5f0579eabfc1c5818eed30cfe1fe84, 5.16.20, <=4.9.*, <c4e2f577271e158d87a916afb4e87415a88ce856, <564d4eceb97eaf381dd6ef6470b06377bb50c95a, <=5.10.*, <cbd96d6cad6625feba9c8d101ed4977d53e82f8e, 2.6.30, 4.9.311, <=4.14.*, 5.17.3, <f4de974019a0adf34d0e7de6b86252f1bd266b06, 5.4.189, <=5.4.*, <2.6.30, <=4.19.*, <9d7d83d0399e23d66fd431b553842a84ac10398f, 5.10.111, <=5.16.*, 4.14.276, <=*, 4.19.238, <=5.15.*, <fc8f7752a82f4accb99c0f1a868906ba1eb7b86f, <be2f81024e7981565d90a4c9ca3067d11b6bca7f, 8e218fb24faef0bfe95bc91b3c05261e20439527) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/f4de974019a0adf34d0e7de6b86252f1bd266b06
• https://git.kernel.org/stable/c/ed3dfdaa8b5f0579eabfc1c5818eed30cfe1fe84
• https://git.kernel.org/stable/c/25efc5d03455c3839249bc77fce5e29ecb54677e
• https://git.kernel.org/stable/c/c4e2f577271e158d87a916afb4e87415a88ce856
• https://git.kernel.org/stable/c/9d7d83d0399e23d66fd431b553842a84ac10398f
• https://git.kernel.org/stable/c/be2f81024e7981565d90a4c9ca3067d11b6bca7f
• https://git.kernel.org/stable/c/fc8f7752a82f4accb99c0f1a868906ba1eb7b86f
• https://git.kernel.org/stable/c/cbd96d6cad6625feba9c8d101ed4977d53e82f8e
• https://git.kernel.org/stable/c/564d4eceb97eaf381dd6ef6470b06377bb50c95a