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).

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History

Fri, 14 Feb 2025 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.17:rc8:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel

Tue, 05 Nov 2024 08:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-05-04T08:20:04.717Z

Reserved: 2024-02-25T13:44:28.315Z

Link: CVE-2022-48629

cve-icon Vulnrichment

Updated: 2024-08-03T15:17:55.625Z

cve-icon NVD

Status : Modified

Published: 2024-03-05T12:15:45.707

Modified: 2025-02-26T07:00:18.270

Link: CVE-2022-48629

cve-icon Redhat

Severity : Low

Publid Date: 2024-03-05T00:00:00Z

Links: CVE-2022-48629 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses