vlan: fix skb_under_panic and races when toggling HW VLAN offload
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.158, 6.12.111, 6.18.51, 7.2.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: vlan: fix skb_under_panic and races when toggling HW VLAN offload Toggling hardware VLAN TX offload (NETIF_F_HW_VLAN_CTAG_TX or NETIF_F_HW_VLAN_STAG_TX) on a lower device invokes vlan_transfer_features(), which dynamically changed vlandev->hard_header_len. This causes two issues: 1. Lockless TX paths (e.g. packet_snd in af_packet.c, ip6_finish_output2) read dev->hard_header_len without holding RTNL lock. Mutating hard_header_len dynamically under RTNL creates a data race where upper layers reserve insufficient headroom based on a stale hard_header_len, resulting in skb_under_panic when vlan_dev_hard_header() is called. 2. In addition, vlan_transfer_features() updated hard_header_len without updating header_ops, causing a mismatch between allocated headroom and header creation. Always setting dev->hard_header_len = real_dev->hard_header_len and dev->needed_headroom = real_dev->needed_headroom + VLAN_HLEN unconditionally ensures: • dev->hard_header_len remains 100% static and immutable at real_dev->hard_header_len, eliminating all dynamic runtime updates and data races on hard_header_len. • Upper layers allocating skbs via LL_RESERVED_SPACE() will always reserve sufficient headroom for software VLAN tag insertion (real_dev->hard_header_len + real_dev->needed_headroom + VLAN_HLEN). • vlandev inherits real_dev->needed_tailroom so underlying trailer/padding/ICV requirements are honored. • AF_PACKET SOCK_RAW network header offsets remain correctly aligned at real_dev->hard_header_len. • vlan_header_ops is used unconditionally. Note to stable teams: Make sure to backport these commits: e16e960d55a4 ("ipvlan: inherit needed_headroom and needed_tailroom from phy_dev") cef51860becd ("macvlan: inherit needed_headroom and needed_tailroom from lowerdev")
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b38d7a4bc9c17e1d437696da25f9fbc286614d9d; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b30fe4de285b9bdaf9508740191f69f7cd83b8fa; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 1517d1996b5236fe69eccd9d253f725e06996eb1; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in a29f3b884ba50217e6f50414f568073221e2bb07; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 447cbe95ebb95392b5d8f6a01c0556826919ce23
- Linux Linux
2.6.12
- KernelLinux
From 2.6.12 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.3