CVE-2022-49625: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: sfc: fix kernel panic when creating VF When creating VFs a kernel panic can happen when calling to efx_ef10_try_update_nic_stats_vf. When releasing a DMA coherent buffer, sometimes, I don't know in what specific circumstances, it has to unmap memory with vunmap. It is disallowed to do that in IRQ context or with BH disabled. Otherwise, we hit this line in vunmap, causing the crash: BUG_ON(in_interrupt()); This patch reenables BH to release the buffer. Log messages when the bug is hit: kernel BUG at mm/vmalloc.c:2727! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 6 PID: 1462 Comm: NetworkManager Kdump: loaded Tainted: G I --------- --- 5.14.0-119.el9.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:vunmap+0x2e/0x30 ...skip... Call Trace: __iommu_dma_free+0x96/0x100 efx_nic_free_buffer+0x2b/0x40 [sfc] efx_ef10_try_update_nic_stats_vf+0x14a/0x1c0 [sfc] efx_ef10_update_stats_vf+0x18/0x40 [sfc] efx_start_all+0x15e/0x1d0 [sfc] efx_net_open+0x5a/0xe0 [sfc] __dev_open+0xe7/0x1a0 __dev_change_flags+0x1d7/0x240 dev_change_flags+0x21/0x60 ...skip...

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.2 — 4.9.324
linux	linux_kernel	4.10 — 4.14.289
linux	linux_kernel	4.15 — 4.19.253
linux	linux_kernel	4.20 — 5.4.207
linux	linux_kernel	5.5 — 5.10.132
linux	linux_kernel	5.11 — 5.15.56
linux	linux_kernel	5.16 — 5.18.13
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/16662524ec5da801fb78a1afcaf6e782f1cf103a https://git.kernel.org/stable/c/68e5f32f0de9594629ff9e599294d9801c6187de https://git.kernel.org/stable/c/82bcb730f856086f033e6c04082eb4503d4c2fa4 https://git.kernel.org/stable/c/ada74c5539eba06cf8b47d068f92e0b3963a9a6e https://git.kernel.org/stable/c/b82e4ad58a7fb72456503958a93060f87896e629 https://git.kernel.org/stable/c/b9072305270579a9d6afc9b926166231e5b1a7c8 https://git.kernel.org/stable/c/d9840212a9c00507347c703f4fdeda16400407e0 https://git.kernel.org/stable/c/da346adcf5573fd8663cabfdfe8371009629a906

Frequently Asked Questions

What is CVE-2022-49625? +

In the Linux kernel, the following vulnerability has been resolved: sfc: fix kernel panic when creating VF When creating VFs a kernel panic can happen when calling to efx_ef10_try_update_nic_stats_vf. When releasing a DMA coherent buffer, sometimes, I don't know in what specific circumstances, it has to unmap memory with vunmap. It is disallowed to do that in IRQ context or with BH disabled. Otherwise, we hit this line in vunmap, causing the crash: BUG_ON(in_interrupt()); This patch reenables BH to release the buffer. Log messages when the bug is hit: kernel BUG at mm/vmalloc.c:2727! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 6 PID: 1462 Comm: NetworkManager Kdump: loaded Tainted: G I --------- --- 5.14.0-119.el9.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:vunmap+0x2e/0x30 ...skip... Call Trace: __iommu_dma_free+0x96/0x100 efx_nic_free_buffer+0x2b/0x40 [sfc] efx_ef10_try_update_nic_stats_vf+0x14a/0x1c0 [sfc] efx_ef10_update_stats_vf+0x18/0x40 [sfc] efx_start_all+0x15e/0x1d0 [sfc] efx_net_open+0x5a/0xe0 [sfc] __dev_open+0xe7/0x1a0 __dev_change_flags+0x1d7/0x240 dev_change_flags+0x21/0x60 ...skip... It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2022-49625? +

CVE-2022-49625 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2022-49625? +

CVE-2022-49625 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2022-49625? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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