CVE-2021-47224

net: ll_temac: Make sure to free skb when it is completely used

State: Published
Severity: 7.8 High
Published: May 21, 2024
Updated: Aug 5, 2026
Reserved: Apr 10, 2024

Description

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

net: ll_temac: Make sure to free skb when it is completely used

With the skb pointer piggy-backed on the TX BD, we have a simple and efficient way to free the skb buffer when the frame has been transmitted. But in order to avoid freeing the skb while there are still fragments from the skb in use, we need to piggy-back on the TX BD of the skb, not the first.

Without this, we are doing use-after-free on the DMA side, when the first BD of a multi TX BD packet is seen as completed in xmit_done, and the remaining BDs are still being processed.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux
3.1	6.2 Medium	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	92744989533cbe85e8057935d230e128810168ce to before 6d120ab4dc39a543c6b63361e1d0541c382900a3Affected 92744989533cbe85e8057935d230e128810168ce to before 019ab7d044d0ebf97e1236bb8935b7809be92358Affected 92744989533cbe85e8057935d230e128810168ce to before e8afe05bd359ebe12a61dbdc94c06c00ea3e8d4bAffected 92744989533cbe85e8057935d230e128810168ce to before 6aa32217a9a446275440ee8724b1ecaf1838df47Affected
LinuxLinux	2.6.31Affected before 2.6.31Not affected 5.4.128 through 5.4.Not affected 5.10.46 through 5.10.Not affected 5.12.13 through 5.12.*Not affected 5.13 and laterNot affected

References

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