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Fencer Vulns
high 8.1

CVE-2022-48629 json

crypto: qcom-rng - ensure buffer for generate is completely filled

published 2024-03-05 2 y ago modified 2026-08-05 3 mo ago also EUVD-2022-51324

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

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

crypto: qcom-rng - ensure buffer for generate is completely filled

The generate function in struct rng_alg expects that the destination buffer is completely filled if the function returns 0. qcom_rng_read() can run into a situation where the buffer is partially filled with randomness and the remaining part of the buffer is zeroed since qcom_rng_generate() doesn't check the return value. This issue can be reproduced by running the following from libkcapi:

kcapi-rng -b 9000000 > OUTFILE

The generated OUTFILE will have three huge sections that contain all zeros, and this is caused by the code where the test 'val & PRNG_STATUS_DATA_AVAIL' fails.

Let's fix this issue by ensuring that qcom_rng_read() always returns with a full buffer if the function returns success. Let's also have qcom_rng_generate() return the correct value.

Here's some statistics from the ent project (https://www.fourmilab.ch/random/) that shows information about the quality of the generated numbers:

$ ent -c qcom-random-before Value Char Occurrences Fraction 0 606748 0.067416 1 33104 0.003678 2 33001 0.003667 ... 253 � 32883 0.003654 254 � 33035 0.003671 255 � 33239 0.003693

Total: 9000000 1.000000

Entropy = 7.811590 bits per byte.

Optimum compression would reduce the size of this 9000000 byte file by 2 percent.

Chi square distribution for 9000000 samples is 9329962.81, and randomly would exceed this value less than 0.01 percent of the times.

Arithmetic mean value of data bytes is 119.3731 (127.5 = random). Monte Carlo value for Pi is 3.197293333 (error 1.77 percent). Serial correlation coefficient is 0.159130 (totally uncorrelated = 0.0).

Without this patch, the results of the chi-square test is 0.01%, and the numbers are certainly not random according to ent's project page. The results improve with this patch:

$ ent -c qcom-random-after Value Char Occurrences Fraction 0 35432 0.003937 1 35127 0.003903 2 35424 0.003936 ... 253 � 35201 0.003911 254 � 34835 0.003871 255 � 35368 0.003930

Total: 9000000 1.000000

Entropy = 7.999979 bits per byte.

Optimum compression would reduce the size of this 9000000 byte file by 0 percent.

Chi square distribution for 9000000 samples is 258.77, and randomly would exceed this value 42.24 percent of the times.

Arithmetic mean value of data bytes is 127.5006 (127.5 = random). Monte Carlo value for Pi is 3.141277333 (error 0.01 percent). Serial correlation coefficient is 0.000468 (totally uncorrelated = 0.0).

This change was tested on a Nexus 5 phone (msm8974 SoC).

Patch / fix

  • Linux Linux 4.19.236, 5.4.187, 5.10.108, 5.15.31, 5.16.17, 5.17
  • linux Debian 14, Debian 13, Debian 12 5.16.18-1

debian advisories DEBIAN-CVE-2022-48629

  • linux Ubuntu 20.04 LTS 5.4.0-117.132
  • linux Ubuntu 22.04 LTS 5.15.0-37.39
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1078.84
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1011.14
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1078.84
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1008.12
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1008.10
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1026.29

ubuntu advisories UBUNTU-CVE-2022-48629

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.59.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.59.1

suse advisories SUSE-SU-2024:1490-1SUSE-SU-2024:1480-1SUSE-SU-2024:1466-1SUSE-SU-2024:1321-1SUSE-SU-2024:1320-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-48629 updated cvss 5.5

kernel: crypto: qcom-rng - ensure buffer for generate is completely filled

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • git.kernel.org https://git.kernel.org/stable/c/a8e32bbb96c25b7ab29b1894dcd45e0b3b08fd9d referenced PoC, tagged "exploit" by a source, unverified
  • git.kernel.org https://git.kernel.org/stable/c/184f7bd08ce56f003530fc19f160d54e75bf5c9d referenced PoC, tagged "exploit" by a source, unverified
  • git.kernel.org https://git.kernel.org/stable/c/0f9b7b8df17525e464294c916acc8194ce38446b referenced PoC, tagged "exploit" by a source, unverified
  • git.kernel.org https://git.kernel.org/stable/c/ab9337c7cb6f875b6286440b1adfbeeef2b2b2bd referenced PoC, tagged "exploit" by a source, unverified
  • git.kernel.org https://git.kernel.org/stable/c/485995cbc98a4f77cfd4f8ed4dd7ff8ab262964d referenced PoC, tagged "exploit" by a source, unverified
  • git.kernel.org https://git.kernel.org/stable/c/a680b1832ced3b5fa7c93484248fd221ea0d614b referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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