CVE-2022-49648

Published Feb 26, 2025

Last updated a year ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Fix memory leak problem This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac. As commit 46bbe5c671e0 ("tracing: fix double free") said, the "double free" problem reported by clang static analyzer is: > In parse_var_defs() if there is a problem allocating > var_defs.expr, the earlier var_defs.name is freed. > This free is duplicated by free_var_defs() which frees > the rest of the list. However, if there is a problem allocating N-th var_defs.expr: + in parse_var_defs(), the freed 'earlier var_defs.name' is actually the N-th var_defs.name; + then in free_var_defs(), the names from 0th to (N-1)-th are freed; IF ALLOCATING PROBLEM HAPPENED HERE!!! -+ \ | 0th 1th (N-1)-th N-th V +-------------+-------------+-----+-------------+----------- var_defs: | name | expr | name | expr | ... | name | expr | name | /// +-------------+-------------+-----+-------------+----------- These two frees don't act on same name, so there was no "double free" problem before. Conversely, after that commit, we get a "memory leak" problem because the above "N-th var_defs.name" is not freed. If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th var_defs.expr allocated, then execute on shell like: $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' > \ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger Then kmemleak reports: unreferenced object 0xffff8fb100ef3518 (size 8): comm "bash", pid 196, jiffies 4295681690 (age 28.538s) hex dump (first 8 bytes): 76 31 00 00 b1 8f ff ff v1...... backtrace: [<0000000038fe4895>] kstrdup+0x2d/0x60 [<00000000c99c049a>] event_hist_trigger_parse+0x206f/0x20e0 [<00000000ae70d2cc>] trigger_process_regex+0xc0/0x110 [<0000000066737a4c>] event_trigger_write+0x75/0xd0 [<000000007341e40c>] vfs_write+0xbb/0x2a0 [<0000000087fde4c2>] ksys_write+0x59/0xd0 [<00000000581e9cdf>] do_syscall_64+0x3a/0x80 [<00000000cf3b065c>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-401
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-401

Social media

Hype score
Not currently trending

Configurations

Related CVEs

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References

Sources include official advisories and independent security research.