CVE-2022-48647: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: sfc: fix TX channel offset when using legacy interrupts In legacy interrupt mode the tx_channel_offset was hardcoded to 1, but that's not correct if efx_sepparate_tx_channels is false. In that case, the offset is 0 because the tx queues are in the single existing channel at index 0, together with the rx queue. Without this fix, as soon as you try to send any traffic, it tries to get the tx queues from an uninitialized channel getting these errors: WARNING: CPU: 1 PID: 0 at drivers/net/ethernet/sfc/tx.c:540 efx_hard_start_xmit+0x12e/0x170 [sfc] [...] RIP: 0010:efx_hard_start_xmit+0x12e/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [...] RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...]

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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	5.10.122 — 5.10.146
linux	linux_kernel	5.15.47 — 5.15.71
linux	linux_kernel	5.17.15 — 5.18
linux	linux_kernel	5.18.4 — 5.19.12
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/360910b88d1466a90644a4e0533803b594344a2b https://git.kernel.org/stable/c/5f623a77cfc2d501d72bcb4f9ee71721e6c766ff https://git.kernel.org/stable/c/b4afd3878f961d3517f27b3213730fceef77945c https://git.kernel.org/stable/c/f232af4295653afa4ade3230462b3be15ad16419 https://git.kernel.org/stable/c/360910b88d1466a90644a4e0533803b594344a2b https://git.kernel.org/stable/c/5f623a77cfc2d501d72bcb4f9ee71721e6c766ff https://git.kernel.org/stable/c/b4afd3878f961d3517f27b3213730fceef77945c https://git.kernel.org/stable/c/f232af4295653afa4ade3230462b3be15ad16419

Frequently Asked Questions

What is CVE-2022-48647? +

In the Linux kernel, the following vulnerability has been resolved: sfc: fix TX channel offset when using legacy interrupts In legacy interrupt mode the tx_channel_offset was hardcoded to 1, but that's not correct if efx_sepparate_tx_channels is false. In that case, the offset is 0 because the tx queues are in the single existing channel at index 0, together with the rx queue. Without this fix, as soon as you try to send any traffic, it tries to get the tx queues from an uninitialized channel getting these errors: WARNING: CPU: 1 PID: 0 at drivers/net/ethernet/sfc/tx.c:540 efx_hard_start_xmit+0x12e/0x170 [sfc] [...] RIP: 0010:efx_hard_start_xmit+0x12e/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [...] RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...] It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2022-48647? +

CVE-2022-48647 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-2022-48647? +

CVE-2022-48647 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-2022-48647? +

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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CVE-2022-48647