7.8

CVE-2022-49626

sfc: fix use after free when disabling sriov

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

sfc: fix use after free when disabling sriov

Use after free is detected by kfence when disabling sriov. What was read
after being freed was vf->pci_dev: it was freed from pci_disable_sriov
and later read in efx_ef10_sriov_free_vf_vports, called from
efx_ef10_sriov_free_vf_vswitching.

Set the pointer to NULL at release time to not trying to read it later.

Reproducer and dmesg log (note that kfence doesn't detect it every time):
$ echo 1 > /sys/class/net/enp65s0f0np0/device/sriov_numvfs
$ echo 0 > /sys/class/net/enp65s0f0np0/device/sriov_numvfs

 BUG: KFENCE: use-after-free read in efx_ef10_sriov_free_vf_vswitching+0x82/0x170 [sfc]

 Use-after-free read at 0x00000000ff3c1ba5 (in kfence-#224):
  efx_ef10_sriov_free_vf_vswitching+0x82/0x170 [sfc]
  efx_ef10_pci_sriov_disable+0x38/0x70 [sfc]
  efx_pci_sriov_configure+0x24/0x40 [sfc]
  sriov_numvfs_store+0xfe/0x140
  kernfs_fop_write_iter+0x11c/0x1b0
  new_sync_write+0x11f/0x1b0
  vfs_write+0x1eb/0x280
  ksys_write+0x5f/0xe0
  do_syscall_64+0x5c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 kfence-#224: 0x00000000edb8ef95-0x00000000671f5ce1, size=2792, cache=kmalloc-4k

 allocated by task 6771 on cpu 10 at 3137.860196s:
  pci_alloc_dev+0x21/0x60
  pci_iov_add_virtfn+0x2a2/0x320
  sriov_enable+0x212/0x3e0
  efx_ef10_sriov_configure+0x67/0x80 [sfc]
  efx_pci_sriov_configure+0x24/0x40 [sfc]
  sriov_numvfs_store+0xba/0x140
  kernfs_fop_write_iter+0x11c/0x1b0
  new_sync_write+0x11f/0x1b0
  vfs_write+0x1eb/0x280
  ksys_write+0x5f/0xe0
  do_syscall_64+0x5c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 freed by task 6771 on cpu 12 at 3170.991309s:
  device_release+0x34/0x90
  kobject_cleanup+0x3a/0x130
  pci_iov_remove_virtfn+0xd9/0x120
  sriov_disable+0x30/0xe0
  efx_ef10_pci_sriov_disable+0x57/0x70 [sfc]
  efx_pci_sriov_configure+0x24/0x40 [sfc]
  sriov_numvfs_store+0xfe/0x140
  kernfs_fop_write_iter+0x11c/0x1b0
  new_sync_write+0x11f/0x1b0
  vfs_write+0x1eb/0x280
  ksys_write+0x5f/0xe0
  do_syscall_64+0x5c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 4.2 < 4.9.324
Linux ≫ Linux Kernel Version >= 4.10 < 4.14.289
Linux ≫ Linux Kernel Version >= 4.15 < 4.19.253
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.207
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.132
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.56
Linux ≫ Linux Kernel Version >= 5.16 < 5.18.13
Linux ≫ Linux Kernel Version5.19 Updaterc1
Linux ≫ Linux Kernel Version5.19 Updaterc2
Linux ≫ Linux Kernel Version5.19 Updaterc3
Linux ≫ Linux Kernel Version5.19 Updaterc4
Linux ≫ Linux Kernel Version5.19 Updaterc5
Linux ≫ Linux Kernel Version5.19 Updaterc6
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.26% 0.173
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
134c704f-9b21-4f2e-91b3-4a467353bcc0 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

https://git.kernel.org/stable/c/3199e34912d84cdfb8a93a984c5ae5c73fb13e84
Patch
https://git.kernel.org/stable/c/58d93e9d160c0de6d867c7eb4c2206671a351eb1
Patch
https://git.kernel.org/stable/c/9c854ae512b89229aeee93849e9bd4c115b37909
Patch
https://git.kernel.org/stable/c/bcad880865bfb421885364b1f0c7351280fe2b97
Patch
https://git.kernel.org/stable/c/c2240500817b3b4b996cdf2a461a3a5679f49b94
Patch
https://git.kernel.org/stable/c/c9e75bb22a26e391f189f5a5133dd63dcb57fdaa
Patch
https://git.kernel.org/stable/c/e435c4aeeaa073091f7f3b7735af2ef5c97d63f2
Patch
https://git.kernel.org/stable/c/ebe41da5d47ac0fff877e57bd14c54dccf168827
Patch