CVE-2021-47095: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: ipmi: ssif: initialize ssif_info->client early During probe ssif_info->client is dereferenced in error path. However, it is set when some of the error checking has already been done. This causes following kernel crash if an error path is taken: [ 30.645593][ T674] ipmi_ssif 0-000e: ipmi_ssif: Not probing, Interface already present [ 30.657616][ T674] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000088 ... [ 30.657723][ T674] pc : __dev_printk+0x28/0xa0 [ 30.657732][ T674] lr : _dev_err+0x7c/0xa0 ... [ 30.657772][ T674] Call trace: [ 30.657775][ T674] __dev_printk+0x28/0xa0 [ 30.657778][ T674] _dev_err+0x7c/0xa0 [ 30.657781][ T674] ssif_probe+0x548/0x900 [ipmi_ssif 62ce4b08badc1458fd896206d9ef69a3c31f3d3e] [ 30.657791][ T674] i2c_device_probe+0x37c/0x3c0 ... Initialize ssif_info->client before any error path can be taken. Clear i2c_client data in the error path to prevent the dangling pointer from leaking.

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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	5.4 — 5.4.169
linux	linux_kernel	5.5 — 5.10.89
linux	linux_kernel	5.11 — 5.15.12
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/1f6ab847461ce7dd89ae9db2dd4658c993355d7c https://git.kernel.org/stable/c/34f35f8f14bc406efc06ee4ff73202c6fd245d15 https://git.kernel.org/stable/c/77a7311ca167aa5b7055c549a940a56e73ee5f29 https://git.kernel.org/stable/c/8efd6a3391f7b0b19fb0c38e50add06ca30c94af https://git.kernel.org/stable/c/1f6ab847461ce7dd89ae9db2dd4658c993355d7c https://git.kernel.org/stable/c/34f35f8f14bc406efc06ee4ff73202c6fd245d15 https://git.kernel.org/stable/c/77a7311ca167aa5b7055c549a940a56e73ee5f29 https://git.kernel.org/stable/c/8efd6a3391f7b0b19fb0c38e50add06ca30c94af

Frequently Asked Questions

What is CVE-2021-47095? +

In the Linux kernel, the following vulnerability has been resolved: ipmi: ssif: initialize ssif_info->client early During probe ssif_info->client is dereferenced in error path. However, it is set when some of the error checking has already been done. This causes following kernel crash if an error path is taken: [ 30.645593][ T674] ipmi_ssif 0-000e: ipmi_ssif: Not probing, Interface already present [ 30.657616][ T674] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000088 ... [ 30.657723][ T674] pc : __dev_printk+0x28/0xa0 [ 30.657732][ T674] lr : _dev_err+0x7c/0xa0 ... [ 30.657772][ T674] Call trace: [ 30.657775][ T674] __dev_printk+0x28/0xa0 [ 30.657778][ T674] _dev_err+0x7c/0xa0 [ 30.657781][ T674] ssif_probe+0x548/0x900 [ipmi_ssif 62ce4b08badc1458fd896206d9ef69a3c31f3d3e] [ 30.657791][ T674] i2c_device_probe+0x37c/0x3c0 ... Initialize ssif_info->client before any error path can be taken. Clear i2c_client data in the error path to prevent the dangling pointer from leaking. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47095? +

CVE-2021-47095 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-2021-47095? +

CVE-2021-47095 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-2021-47095? +

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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