Description
In the Linux kernel, the following vulnerability has been resolved: net/packet: fix TOCTOU race on mmap'd vnet_hdr in tpacket_snd() In tpacket_snd(), when PACKET_VNET_HDR is enabled, vnet_hdr points directly into the mmap'd TX ring buffer shared with userspace. The kernel validates the header via __packet_snd_vnet_parse() but then re-reads all fields later in virtio_net_hdr_to_skb(). A concurrent userspace thread can modify the vnet_hdr fields between validation and use, bypassing all safety checks. The non-TPACKET path (packet_snd()) already correctly copies vnet_hdr to a stack-local variable. All other vnet_hdr consumers in the kernel (tun.c, tap.c, virtio_net.c) also use stack copies. The TPACKET TX path is the only caller of virtio_net_hdr_to_skb() that reads directly from user-controlled shared memory. Fix this by copying vnet_hdr from the mmap'd ring buffer to a stack-local variable before validation and use, consistent with the approach used in packet_snd() and all other callers.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
1d036d25e5609ba73fee6a88db01c306b140d512 to < 0f4c9754956b86de158a4af5278c5cf5bda9439eaffected1d036d25e5609ba73fee6a88db01c306b140d512 to < 714aa973da8163925eda7efd49361ccbee21ee46affected1d036d25e5609ba73fee6a88db01c306b140d512 to < 1490f82353bdabc09265a74e645b07f05cf4188eaffected1d036d25e5609ba73fee6a88db01c306b140d512 to < 74e2db36fe50e3ad9d5300d7fd0e6e2a15a6d121affected1d036d25e5609ba73fee6a88db01c306b140d512 to < 3a1bf9116ea31470b89692585c3910dfe830dcddaffected1d036d25e5609ba73fee6a88db01c306b140d512 to < 28324a3b62d9ce7f9bdd65a8ce63f382041d1b27affected1d036d25e5609ba73fee6a88db01c306b140d512 to < 48a6ef291a17639e1b6ae0fbe9c8b2bb87d7804baffected1d036d25e5609ba73fee6a88db01c306b140d512 to < 2c054e17d9d41f1020376806c7f750834ced4dc5affected
Linux Linux
Default version status: affected
4.6affected0 to < 4.6unaffected5.10.259 to ≤ 5.10.*unaffected5.15.210 to ≤ 5.15.*unaffected6.1.176 to ≤ 6.1.*unaffected6.6.136 to ≤ 6.6.*unaffected6.12.84 to ≤ 6.12.*unaffected6.18.25 to ≤ 6.18.*unaffected7.0.2 to ≤ 7.0.*unaffected7.1 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/0f4c9754956b86de158a4af5278c5cf5bda9439e ↗
- https://git.kernel.org/stable/c/714aa973da8163925eda7efd49361ccbee21ee46 ↗
- https://git.kernel.org/stable/c/1490f82353bdabc09265a74e645b07f05cf4188e ↗
- https://git.kernel.org/stable/c/74e2db36fe50e3ad9d5300d7fd0e6e2a15a6d121 ↗
- https://git.kernel.org/stable/c/3a1bf9116ea31470b89692585c3910dfe830dcdd ↗
- https://git.kernel.org/stable/c/28324a3b62d9ce7f9bdd65a8ce63f382041d1b27 ↗
- https://git.kernel.org/stable/c/48a6ef291a17639e1b6ae0fbe9c8b2bb87d7804b ↗
- https://git.kernel.org/stable/c/2c054e17d9d41f1020376806c7f750834ced4dc5 ↗
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html ↗