Description
In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: bound SGL data length before allocating command buffers nvmet_tcp_map_data() reads the host-controlled 32-bit sgl->length and, for the in-capsule offset descriptor (type 0x01), checks it against port->inline_data_size before use. Any other SGL descriptor type -- including the non-inline transport SGL data-block descriptor (type (NVME_TRANSPORT_SGL_DATA_DESC << 4) | NVME_SGL_FMT_TRANSPORT_A, the type a real host uses for out-of-capsule writes) skips that check entirely and falls straight through to: cmd->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.sg_cnt); with len taken directly from the wire, unbounded up to 4 GiB. nvmet_req_init() only parses the command and never inspects sgl->length, and nvmet_check_transfer_len() -- the only other place transfer_len is validated -- runs later, from req->execute(), after the allocation has already happened. For a write command the target responds with an R2T and parks the command waiting for the host to send the data; if the host (or an unauthenticated peer that simply never follows up) never does, the sgl_alloc() buffer stays resident for the life of the command. NVMe/TCP has no mandatory authentication in the default configuration, so any peer able to reach the target portal and complete a Fabrics connect can drive this with a single crafted command, repeatable across queues and connections for amplification. This is unbounded kernel memory allocation triggered by a remote, effectively unauthenticated peer. Validate len against the same NVMET_TCP_MAXH2CDATA ceiling this file already uses to bound per-PDU H2C data, for every SGL descriptor type, before doing any allocation. This closes the gap for the non-inline descriptor while leaving the existing, tighter inline_data_size check in place for the in-capsule case. Runtime-verified on a v6.19 KASAN stand: with this bound in place, a crafted write command carrying an oversized non-inline SGL length is rejected before sgl_alloc() runs, where the same request previously drove an unbounded ~256 MiB kernel allocation (up to 4 GiB) that stayed resident pending an R2T the host never satisfies.
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
872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < f6e51b09cbaa5f6f6e6a3a9dafa666f76c37aab5affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < f63e89a0310264264923f84406dea05fe752de62affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < 0952541b153e258b99d39cdb03ea6919fdeb41d0affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < 25ad03d5c0e858c4b63f1e4b6d461d2af1b30b22affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < d2acc96c528d589f5827cfb90e8e9229dd9d8cb4affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < 6d27199ebe8cb223022150f74be13f154a964474affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < 14dbe37681a6a7e346fc147bb363ec7cca3180a0affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < d895e66628f939edbb98608f6e033d3d39e6e546affected872d26a391da92ed8f0c0f5cb5fef428067b7f30 to < 4a3f00262a044e8e15064b1a6860968bf0500bf4affected
Linux Linux
Default version status: affected
5.0affected0 to < 5.0unaffected5.10.269 to ≤ 5.10.*unaffected5.15.220 to ≤ 5.15.*unaffected6.1.187 to ≤ 6.1.*unaffected6.6.156 to ≤ 6.6.*unaffected6.12.106 to ≤ 6.12.*unaffected6.18.47 to ≤ 6.18.*unaffected7.1.11 to ≤ 7.1.*unaffected7.2.1 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/f6e51b09cbaa5f6f6e6a3a9dafa666f76c37aab5 ↗
- https://git.kernel.org/stable/c/f63e89a0310264264923f84406dea05fe752de62 ↗
- https://git.kernel.org/stable/c/0952541b153e258b99d39cdb03ea6919fdeb41d0 ↗
- https://git.kernel.org/stable/c/25ad03d5c0e858c4b63f1e4b6d461d2af1b30b22 ↗
- https://git.kernel.org/stable/c/d2acc96c528d589f5827cfb90e8e9229dd9d8cb4 ↗
- https://git.kernel.org/stable/c/6d27199ebe8cb223022150f74be13f154a964474 ↗
- https://git.kernel.org/stable/c/14dbe37681a6a7e346fc147bb363ec7cca3180a0 ↗
- https://git.kernel.org/stable/c/d895e66628f939edbb98608f6e033d3d39e6e546 ↗
- https://git.kernel.org/stable/c/4a3f00262a044e8e15064b1a6860968bf0500bf4 ↗