CVE-2021-47280
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2021-47280
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-47280.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2021-47280
- Related
- Published
- 2024-05-21T15:15:16Z
- Modified
- 2024-09-11T02:00:06Z
- Summary
- [none]
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
drm: Fix use-after-free read in drm_getunique()
There is a time-of-check-to-time-of-use error in drmgetunique() due to retrieving filepriv->master prior to locking the device's master mutex.
An example can be seen in the crash report of the use-after-free error found by Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803
In the report, the master pointer was used after being freed. This is because another process had acquired the device's master mutex in drmsetmasterioctl(), then overwrote fpriv->master in drmnewset_master(). The old value of fpriv->master was subsequently freed before the mutex was unlocked.
To fix this, we lock the device's master mutex before retrieving the pointer from from fpriv->master. This patch passes the Syzbot reproducer test.
- References
-
- https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4
- https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6
- https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9
- https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3
- https://git.kernel.org/stable/c/b436acd1cf7fac0ba987abd22955d98025c80c2b
- https://git.kernel.org/stable/c/f773f8cccac13c7e7bbd9182e7996c727742488e
- https://security-tracker.debian.org/tracker/CVE-2021-47280
Affected packages
Debian:11 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:12 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:13 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source