Description
In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg When the server answers an RTRS READ, rdma_write_sg() builds the source scatter/gather entry for the IB_WR_RDMA_WRITE that returns data to the peer. Its length is taken directly from the wire descriptor: plist->length = le32_to_cpu(id->rd_msg->desc[0].len); rd_msg points into the chunk buffer that the remote peer filled via RDMA-WRITE-WITH-IMM (rtrs_srv_rdma_done() -> process_io_req() -> process_read()), so desc[0].len is attacker-controlled and, before this change, was only rejected when zero. The source address is the fixed chunk start (dma_addr[msg_id]) and the source lkey is the PD-wide local_dma_lkey, which is not tied to the chunk's MR mapping, so the verbs layer does not constrain the transfer length to max_chunk_size. msg_id and off are bounded against queue_depth and max_chunk_size in rtrs_srv_rdma_done(), but desc[0].len is a separate field that was not checked against the chunk size. A peer that advertises desc[0].len larger than max_chunk_size can make the posted RDMA write read past the chunk's mapped region. The resulting behaviour depends on the IOMMU configuration: with no IOMMU or in passthrough mode the read may extend into memory adjacent to the chunk and be returned to the peer, which can disclose host memory; with a translating IOMMU the out-of-range access is expected to fault and abort the connection. In either case the transfer exceeds what the protocol permits and is driven by a remote peer. Reject a descriptor length above max_chunk_size, mirroring the existing off >= max_chunk_size bound in rtrs_srv_rdma_done(). Legitimate clients do not exceed it: the client sets desc[0].len to its MR length, which is capped at the negotiated max_io_size (max_chunk_size - MAX_HDR_SIZE).
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
9cb837480424e78ed585376f944088246685aec3 to < a35b7a8728a53ddc80b323970689fa5985816836affected9cb837480424e78ed585376f944088246685aec3 to < 68c09762172f6224e9ddf9b0a60bacbb36e443ebaffected9cb837480424e78ed585376f944088246685aec3 to < 6cada540150894e81042a0ae0c796a21a9a877daaffected9cb837480424e78ed585376f944088246685aec3 to < 2912f3d40355dabc08fdbaaf2764d02445fe88dcaffected9cb837480424e78ed585376f944088246685aec3 to < 6f40246f4312fdbab5a13cc440adebf95eb2aa66affected9cb837480424e78ed585376f944088246685aec3 to < 5a45d0aa1fa50a333ce5763ade744e2d89838667affected9cb837480424e78ed585376f944088246685aec3 to < da3e44add94b05dfde56f898421922f5cf35705faffected9cb837480424e78ed585376f944088246685aec3 to < 963af8d97a8c6a117134a8d0db1415e0489200b1affected
Linux Linux
Default version status: affected
5.8affected0 to < 5.8unaffected5.10.266 to ≤ 5.10.*unaffected5.15.212 to ≤ 5.15.*unaffected6.1.178 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.96 to ≤ 6.12.*unaffected6.18.39 to ≤ 6.18.*unaffected7.1.4 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/a35b7a8728a53ddc80b323970689fa5985816836 ↗
- https://git.kernel.org/stable/c/68c09762172f6224e9ddf9b0a60bacbb36e443eb ↗
- https://git.kernel.org/stable/c/6cada540150894e81042a0ae0c796a21a9a877da ↗
- https://git.kernel.org/stable/c/2912f3d40355dabc08fdbaaf2764d02445fe88dc ↗
- https://git.kernel.org/stable/c/6f40246f4312fdbab5a13cc440adebf95eb2aa66 ↗
- https://git.kernel.org/stable/c/5a45d0aa1fa50a333ce5763ade744e2d89838667 ↗
- https://git.kernel.org/stable/c/da3e44add94b05dfde56f898421922f5cf35705f ↗
- https://git.kernel.org/stable/c/963af8d97a8c6a117134a8d0db1415e0489200b1 ↗