From 3a6d89836ab09d53f4c32c57588689a378ce4363 Mon Sep 17 00:00:00 2001 From: Xixin Liu Date: Wed, 1 Jul 2026 14:30:00 +0800 Subject: [PATCH] nvme-auth: use crypto_memneq for DH-HMAC-CHAP response comparison DH-HMAC-CHAP authentication compares HMAC response digests with memcmp(). Standard memcmp() may stop at the first differing byte, which can leak timing information to a remote attacker and allow incremental recovery of the expected digest. Use crypto_memneq() for constant-time comparison on both the host path that validates the controller Success1 response and the target path that validates the host Reply digest. Other memcmp() uses in the NVMe auth code (e.g. fixed string prefix checks) are not security-sensitive and are left unchanged. Signed-off-by: Xixin Liu Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch --- drivers/nvme/host/auth.c | 3 ++- drivers/nvme/target/fabrics-cmd-auth.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c index 16de4499a8e7..e55920642f2c 100644 --- a/drivers/nvme/host/auth.c +++ b/drivers/nvme/host/auth.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "nvme.h" #include "fabrics.h" #include @@ -361,7 +362,7 @@ static int nvme_auth_process_dhchap_success1(struct nvme_ctrl *ctrl, return 0; /* Validate controller response */ - if (memcmp(chap->response, data->rval, data->hl)) { + if (crypto_memneq(chap->response, data->rval, data->hl)) { dev_dbg(ctrl->device, "%s: qid %d ctrl response %*ph\n", __func__, chap->qid, (int)chap->hash_len, data->rval); dev_dbg(ctrl->device, "%s: qid %d host response %*ph\n", diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c index 45820a12750d..03529e19698b 100644 --- a/drivers/nvme/target/fabrics-cmd-auth.c +++ b/drivers/nvme/target/fabrics-cmd-auth.c @@ -9,6 +9,7 @@ #include #include #include +#include #include "nvmet.h" static void nvmet_auth_expired_work(struct work_struct *work) @@ -177,7 +178,7 @@ static u8 nvmet_auth_reply(struct nvmet_req *req, void *d, u32 tl) return NVME_AUTH_DHCHAP_FAILURE_FAILED; } - if (memcmp(data->rval, response, data->hl)) { + if (crypto_memneq(data->rval, response, data->hl)) { pr_info("ctrl %d qid %d host response mismatch\n", ctrl->cntlid, req->sq->qid); pr_debug("ctrl %d qid %d rval %*ph\n",