CVE-2021-47649

udmabuf: validate ubuf->pagecount

Description

In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array().

N/A

CVSS

Severity:

EPSS 0.05%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/5d50f851dd307c07ca5591297093f19967c834a9
https://git.kernel.org/stable/c/b267a8118c2b171bf7d67b90ed64154eeab9fae0
https://git.kernel.org/stable/c/811b667cefbea9cb7511a874b169d6a92907137e
https://git.kernel.org/stable/c/a3728d32fc61eb0fe283cb8ff60b2c8f751e2202
https://git.kernel.org/stable/c/9e9b4a269f84d3230f2af84ff42322db676440d9
https://git.kernel.org/stable/c/2b6dd600dd72573c23ea180b5b0b2f1813405882

Frequently Asked Questions

What is the severity of CVE-2021-47649?: CVE-2021-47649 has not yet been assigned a CVSS score.
How to fix CVE-2021-47649?: To fix CVE-2021-47649, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47649 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2021-47649 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47649?: CVE-2021-47649 affects Linux Linux, Linux Linux.

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