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CVE-2022-48914

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <5.16.13, <dcf4ff7a48e7598e6b10126cc02177abb8ae4f3f, a5d8e6189b134f5db61be5cd59cf5a74bb01edc7, <4.19.233, 5.16.3, <5.15.27, 0abd3f9903fae6ecf8db3c89a459971fe7925499, d7dac083414eb5bb99a6d2ed53dc2c1b405224e5, 5.4.174, 35cad2003b6447932cfe91f795090586306738e8, 443133330a5d4a3fd429179d460cc297724fefe8, 5.15.17, 5.10.94, c5eb468cbc1fa663bf0cc6c5360802dea4e611c2, <5.4.183, <a1753d5c29a6fb9a8966dcf04cb4f3b71e303ae8, <47e2f166ed9fe17f24561d6315be2228f6a90209, <198cdc287769c717dafff5887c6125cb7a373bf3, 4.19.226, <5.10.104, <b40c912624775a21da32d1105e158db5f6d0554a, <a63eb1e4a2e1a191a90217871e67fba42fd39255

Description

In the Linux kernel, the following vulnerability has been resolved: xen/netfront: destroy queues before real_num_tx_queues is zeroed xennet_destroy_queues() relies on info->netdev->real_num_tx_queues to delete queues. Since d7dac083414eb5bb99a6d2ed53dc2c1b405224e5 ("net-sysfs: update the queue counts in the unregistration path"), unregister_netdev() indirectly sets real_num_tx_queues to 0. Those two facts together means, that xennet_destroy_queues() called from xennet_remove() cannot do its job, because it's called after unregister_netdev(). This results in kfree-ing queues that are still linked in napi, which ultimately crashes: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 52 Comm: xenwatch Tainted: G W 5.16.10-1.32.fc32.qubes.x86_64+ #226 RIP: 0010:free_netdev+0xa3/0x1a0 Code: ff 48 89 df e8 2e e9 00 00 48 8b 43 50 48 8b 08 48 8d b8 a0 fe ff ff 48 8d a9 a0 fe ff ff 49 39 c4 75 26 eb 47 e8 ed c1 66 ff <48> 8b 85 60 01 00 00 48 8d 95 60 01 00 00 48 89 ef 48 2d 60 01 00 RSP: 0000:ffffc90000bcfd00 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff88800edad000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffc90000bcfc30 RDI: 00000000ffffffff RBP: fffffffffffffea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88800edad050 R13: ffff8880065f8f88 R14: 0000000000000000 R15: ffff8880066c6680 FS: 0000000000000000(0000) GS:ffff8880f3300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000e998c006 CR4: 00000000003706e0 Call Trace: <TASK> xennet_remove+0x13d/0x300 [xen_netfront] xenbus_dev_remove+0x6d/0xf0 __device_release_driver+0x17a/0x240 device_release_driver+0x24/0x30 bus_remove_device+0xd8/0x140 device_del+0x18b/0x410 ? _raw_spin_unlock+0x16/0x30 ? klist_iter_exit+0x14/0x20 ? xenbus_dev_request_and_reply+0x80/0x80 device_unregister+0x13/0x60 xenbus_dev_changed+0x18e/0x1f0 xenwatch_thread+0xc0/0x1a0 ? do_wait_intr_irq+0xa0/0xa0 kthread+0x16b/0x190 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x22/0x30 </TASK> Fix this by calling xennet_destroy_queues() from xennet_uninit(), when real_num_tx_queues is still available. This ensures that queues are destroyed when real_num_tx_queues is set to 0, regardless of how unregister_netdev() was called. Originally reported at https://github.com/QubesOS/qubes-issues/issues/7257

Gravité et risque d'exploitation

CVE-2022-48914 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 0.21 %, ce qui la place devant 11.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <5.16.13, <dcf4ff7a48e7598e6b10126cc02177abb8ae4f3f, a5d8e6189b134f5db61be5cd59cf5a74bb01edc7, <4.19.233, 5.16.3, <5.15.27, 0abd3f9903fae6ecf8db3c89a459971fe7925499, d7dac083414eb5bb99a6d2ed53dc2c1b405224e5, 5.4.174, 35cad2003b6447932cfe91f795090586306738e8, 443133330a5d4a3fd429179d460cc297724fefe8, 5.15.17, 5.10.94, c5eb468cbc1fa663bf0cc6c5360802dea4e611c2, <5.4.183, <a1753d5c29a6fb9a8966dcf04cb4f3b71e303ae8, <47e2f166ed9fe17f24561d6315be2228f6a90209, <198cdc287769c717dafff5887c6125cb7a373bf3, 4.19.226, <5.10.104, <b40c912624775a21da32d1105e158db5f6d0554a, <a63eb1e4a2e1a191a90217871e67fba42fd39255) 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

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