drm: Fix use-after-free read in drm_getunique()
There is a time-of-check-to-time-of-use error in drm_getunique() due
to retrieving file_priv->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
drm_setmaster_ioctl(), then overwrote fpriv->master in
drm_new_set_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.
Metrics
Affected Vendors & Products
Mon, 05 May 2025 21:15:00 +0000
Type | Values Removed | Values Added |
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Metrics |
ssvc
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Tue, 24 Dec 2024 17:00:00 +0000
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First Time appeared |
Linux
Linux linux Kernel |
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CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* 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:*:*:*:*:*:* |
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Vendors & Products |
Linux
Linux linux Kernel |
|
Metrics |
cvssV3_1
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cvssV3_1
|
Wed, 11 Sep 2024 18:30:00 +0000
Type | Values Removed | Values Added |
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Metrics |
ssvc
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Wed, 11 Sep 2024 13:30:00 +0000
Type | Values Removed | Values Added |
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Metrics |
ssvc
|

Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-05-04T07:07:47.801Z
Reserved: 2024-05-21T13:27:52.128Z
Link: CVE-2021-47280

Updated: 2024-08-04T05:32:08.124Z

Status : Analyzed
Published: 2024-05-21T15:15:16.277
Modified: 2024-12-24T16:31:41.267
Link: CVE-2021-47280


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