From: Michael Bommarito <michael.bommarito@gmail.com> mainline inclusion from mainline-v7.1 commit 29e7b925ae6df64894e82ab6419994dc25580a8a category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15861 CVE: CVE-2026-53176 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- In drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done() computes the login request payload length as wc->byte_len minus ISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int. A remote iSER initiator can post a login Send work request carrying fewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows and login_req_len becomes negative. isert_rx_login_req() then reads that negative length back into a signed int, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the min() is signed it keeps the negative value; the value is then passed as the memcpy() length and sign-extended to a multi-gigabyte size_t. The copy into the 8192-byte login->req_buf runs far out of bounds and faults, crashing the target node. The login phase precedes iSCSI authentication, so no credentials are required to reach this path. Reject any login PDU shorter than ISER_HEADERS_LEN before the subtraction, mirroring the existing early return on a failed work completion, so login_req_len can never go negative. The upper bound was already safe: a posted login buffer cannot deliver more than ISER_RX_PAYLOAD_SIZE, so the difference stays at or below MAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing lower bound needs to be added. Fixes: b8d26b3be8b3 ("iser-target: Add iSCSI Extensions for RDMA (iSER) target driver") Link: https://patch.msgid.link/r/20260602194642.2273217-1-michael.bommarito@gmail.... Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Conflicts: drivers/infiniband/ulp/isert/ib_isert.c [Context differences, unrelated to the fix patch.] Signed-off-by: Xia Fukun <xiafukun@huawei.com> --- drivers/infiniband/ulp/isert/ib_isert.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index f39670c5c25c..97119e8e0751 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -1473,6 +1473,12 @@ isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc) ib_dma_sync_single_for_cpu(ib_dev, isert_conn->login_req_dma, ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE); + if (unlikely(wc->byte_len < ISER_HEADERS_LEN)) { + isert_dbg("login request length %u is too short\n", + wc->byte_len); + return; + } + isert_conn->login_req_len = wc->byte_len - ISER_HEADERS_LEN; if (isert_conn->conn) { -- 2.34.1