CVE-2021-46993

Summary

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

sched: Fix out-of-bound access in uclamp

Util-clamp places tasks in different buckets based on their clamp values for performance reasons. However, the size of buckets is currently computed using a rounding division, which can lead to an off-by-one error in some configurations.

For instance, with 20 buckets, the bucket size will be 1024/20=51. A task with a clamp of 1024 will be mapped to bucket id 1024/51=20. Sadly, correct indexes are in range [0,19], hence leading to an out of bound memory access.

Clamp the bucket id to fix the issue.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux69842cba9ace84849bb9b8edcdf2cefccd97901c < 687f523c134b7f0bd040ee1230f6d17990d54172affected
LinuxLinux69842cba9ace84849bb9b8edcdf2cefccd97901c < f7347c85490b92dd144fa1fba9e1eca501656ab3affected
LinuxLinux69842cba9ace84849bb9b8edcdf2cefccd97901c < 3da3f804b82a0a382d523a21acf4cf3bb35f936daffected
LinuxLinux69842cba9ace84849bb9b8edcdf2cefccd97901c < 42ee47c7e3569d9a0e2cb5053c496d97d380472faffected
LinuxLinux69842cba9ace84849bb9b8edcdf2cefccd97901c < 6d2f8909a5fabb73fe2a63918117943986c39b6caffected
LinuxLinux5.3affected
LinuxLinux0 < 5.3unaffected
LinuxLinux5.4.120 <= 5.4.*unaffected
LinuxLinux5.10.38 <= 5.10.*unaffected
LinuxLinux5.11.22 <= 5.11.*unaffected
LinuxLinux5.12.5 <= 5.12.*unaffected
LinuxLinux5.13 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References