RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe

get_srq_wqe() reads wqe->dma.num_sge from the shared receive queue
buffer, which is mapped into userspace. It validates num_sge against
max_sge, but then re-reads the same field to calculate the memcpy
size. A concurrent userspace thread can modify num_sge between
validation and use, causing a heap buffer overflow when copying the
WQE into qp->resp.srq_wqe.

Read num_sge into a local variable and use it for both the bounds
check and the size calculation.

Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://patch.msgid.link/r/20260518215040.1598586-2-tristan@talencesecurity.com
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

0 files changed, 0 insertions, 0 deletions