RDMA/mlx5: Fix integer overflow of user QP buffer size

Summary

In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix integer overflow of user QP buffer size set_user_buf_size() computes the QP buffer size by left-shifting the user-supplied rq.wqe_cnt and rq.wqe_shift values as signed integers. A sufficiently large rq.wqe_cnt causes signed integer overflow, which is undefined behavior, and yields a small or negative buf_size, causing ib_umem_get() to map a buffer smaller than the hardware will actually write into. Replace the shifts and addition with check_shl_overflow() and check_add_overflow(), rejecting invalid user inputs. Moreover, guard the identical shift computing qp->sq.offset in _create_user_qp() before set_user_buf_size() is reached.

Timeline

1. Sep 17, 2026, 4:09 PM UTCCVE published
2. Oct 19, 2026, 9:03 AM UTCRecord last updated

Affected versions

• Linux Linux

  From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in ccce6b7ef1d7efc59ccba3421e1339c6e63a3d20; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in d99622e40aaa910ade681dfd4dc0fa240a011331; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in c845e5e05140ea1bc64a5b1107942d93c876034d; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in 42fb8aefffff5b458aaa66803364a16e0ea44129; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in d7fa2ff72ad1861eac194a4e0075d504ba8c246e; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in 5b6cfc6d7ff0959dd9766fdc24286a253b59ca77; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in f917707f0de0832b8ab582391b1f64e549995c6c; From e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c · fixed in dec47e4b0fe34afdf38caa72b4408ba95502e5de

• Linux Linux

  3.11

• KernelLinux

  From 3.11.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 8