RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access

mr_check_range() validates that [iova, iova+length) falls within the
registered MR range using wraparound-prone arithmetic:

    if (iova < mr->ibmr.iova ||
        iova + length > mr->ibmr.iova + mr->ibmr.length)

A remote peer can craft an RDMA-Write/Read RETH so that iova + length
wraps to 0 (e.g. iova=0xfffffffffffffff8, length=8), bypassing the
check. rxe_mr_iova_to_index() then computes a huge index (int idx, only
guarded by WARN_ON) and rxe_mr_copy_xarray() dereferences
mr->page_info[huge], causing an out-of-bounds read/write and a kernel
oops that is triggerable by an unauthenticated remote peer.

Rewrite the check in overflow-safe form; the first two clauses guarantee
that the subsequent subtractions do not underflow:

    if (iova < mr->ibmr.iova ||
        length > mr->ibmr.length ||
        iova - mr->ibmr.iova > mr->ibmr.length - length)

With the fix, mr_check_range() returns -EINVAL for the crafted iova and
the responder reports REMOTE_ACCESS_ERROR instead of triggering the OOB.

Fixes: 8700e3e7c4 ("Soft RoCE driver")
Signed-off-by: Gang Yan <yangang@kylinos.cn>
Link: https://patch.msgid.link/20260814093740.292954-1-gang.yan@linux.dev
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Reviewed-by: Shukai Ni <shukai.ni@kuleuven.be>
Tested-by: Shukai Ni <shukai.ni@kuleuven.be>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Gang Yan 2026-08-14 17:37:40 +08:00 committed by Leon Romanovsky
parent ae36a5b609
commit d10e2a0879

View File

@ -33,7 +33,8 @@ int mr_check_range(struct rxe_mr *mr, u64 iova, size_t length)
case IB_MR_TYPE_USER:
case IB_MR_TYPE_MEM_REG:
if (iova < mr->ibmr.iova ||
iova + length > mr->ibmr.iova + mr->ibmr.length) {
length > mr->ibmr.length ||
iova - mr->ibmr.iova > mr->ibmr.length - length) {
rxe_dbg_mr(mr, "iova/length out of range\n");
return -EINVAL;
}