CVE-2021-46990
powerpc/64s: Fix crashes when toggling entry flush barrier
Description
In the Linux kernel, the following vulnerability has been resolved: powerpc/64s: Fix crashes when toggling entry flush barrier The entry flush mitigation can be enabled/disabled at runtime via a debugfs file (entry_flush), which causes the kernel to patch itself to enable/disable the relevant mitigations. However depending on which mitigation we're using, it may not be safe to do that patching while other CPUs are active. For example the following crash: sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20 Shows that we returned to userspace with a corrupted LR that points into the kernel, due to executing the partially patched call to the fallback entry flush (ie. we missed the LR restore). Fix it by doing the patching under stop machine. The CPUs that aren't doing the patching will be spinning in the core of the stop machine logic. That is currently sufficient for our purposes, because none of the patching we do is to that code or anywhere in the vicinity.
INFO
Published Date :
Feb. 28, 2024, 9:15 a.m.
Last Modified :
Dec. 26, 2024, 3:01 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel packages.
- Reboot the system if required.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-46990.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-46990 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-46990
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-46990 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-46990 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Reanalysis by [email protected]
Dec. 26, 2024
Action Type Old Value New Value Changed CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.4.245 up to (excluding) 4.4.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.9.245 up to (excluding) 4.9.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.14.208 up to (excluding) 4.14.233 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19.159 up to (excluding) 4.19.191 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.4.79 up to (excluding) 5.4.120 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10 up to (excluding) 5.10.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.11.22 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.5 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc7:*:*:*:*:*:* OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.4.245 up to (excluding) 4.4.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.9.245 up to (excluding) 4.9.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.14.208 up to (excluding) 4.14.233 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19.159 up to (excluding) 4.19.191 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.4.79 up to (excluding) 5.4.120 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10 up to (excluding) 5.10.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.11.22 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.5 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* -
Initial Analysis by [email protected]
Dec. 24, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NIST NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.4.245 up to (excluding) 4.4.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.9.245 up to (excluding) 4.9.269 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.14.208 up to (excluding) 4.14.233 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.19.159 up to (excluding) 4.19.191 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.4.79 up to (excluding) 5.4.120 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10 up to (excluding) 5.10.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.11.22 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.5 *cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:5.13:rc7:*:*:*:*:*:* Changed Reference Type https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 No Types Assigned https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 Patch Changed Reference Type https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 No Types Assigned https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 Patch Changed Reference Type https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a No Types Assigned https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a Patch Changed Reference Type https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a No Types Assigned https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a Patch Changed Reference Type https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 No Types Assigned https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 Patch Changed Reference Type https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 No Types Assigned https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 Patch Changed Reference Type https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf No Types Assigned https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf Patch Changed Reference Type https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf No Types Assigned https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf Patch Changed Reference Type https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 No Types Assigned https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 Patch Changed Reference Type https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 No Types Assigned https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 Patch Changed Reference Type https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b No Types Assigned https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b Patch Changed Reference Type https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b No Types Assigned https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b Patch Changed Reference Type https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 No Types Assigned https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 Patch Changed Reference Type https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 No Types Assigned https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 Patch Changed Reference Type https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d No Types Assigned https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d Patch Changed Reference Type https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d No Types Assigned https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d Patch Changed Reference Type https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b No Types Assigned https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b Patch Changed Reference Type https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b No Types Assigned https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 Added Reference https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a Added Reference https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 Added Reference https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf Added Reference https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 Added Reference https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b Added Reference https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 Added Reference https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d Added Reference https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 28, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: powerpc/64s: Fix crashes when toggling entry flush barrier The entry flush mitigation can be enabled/disabled at runtime via a debugfs file (entry_flush), which causes the kernel to patch itself to enable/disable the relevant mitigations. However depending on which mitigation we're using, it may not be safe to do that patching while other CPUs are active. For example the following crash: sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20 Shows that we returned to userspace with a corrupted LR that points into the kernel, due to executing the partially patched call to the fallback entry flush (ie. we missed the LR restore). Fix it by doing the patching under stop machine. The CPUs that aren't doing the patching will be spinning in the core of the stop machine logic. That is currently sufficient for our purposes, because none of the patching we do is to that code or anywhere in the vicinity. Added Reference Linux https://git.kernel.org/stable/c/8382b15864e5014261b4f36c2aa89723612ee058 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/0c25a7bb697f2e6ee65b6d63782f675bf129511a [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/ee4b7aab93c2631c3bb0753023c5dda592bb666b [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/2db22ba4e0e103f00e0512e0ecce36ac78c644f8 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/0b4eb172cc12dc102cd0ad013e53ee4463db9508 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/dd0d6117052faace5440db20fc37175efe921c7d [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/5bc00fdda1e934c557351a9c751a205293e68cbf [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/aec86b052df6541cc97c5fca44e5934cbea4963b [No types assigned]