nvmet_auth_challenge() receives its output buffer as a void pointer. sizeof(*d) therefore evaluates to one with GCC and undercounts the fixed challenge header by 15 bytes. A short AUTH_RECEIVE buffer can pass the check before the challenge is copied past the end of its allocation. Use the typed challenge pointer when calculating the response size. BUG: KASAN: slab-out-of-bounds in nvmet_execute_auth_receive (drivers/nvme/target/fabrics-cmd-auth.c:442 drivers/nvme/target/fabrics-cmd-auth.c:569) Write of size 32 by task kworker/1:1H/64 Workqueue: nvmet_tcp_wq nvmet_tcp_io_work Call Trace: nvmet_execute_auth_receive (drivers/nvme/target/fabrics-cmd-auth.c:442 drivers/nvme/target/fabrics-cmd-auth.c:569) nvmet_tcp_try_recv_pdu (drivers/nvme/target/tcp.c:1119 drivers/nvme/target/tcp.c:1243) nvmet_tcp_io_work (drivers/nvme/target/tcp.c:1350 drivers/nvme/target/tcp.c:1382 drivers/nvme/target/tcp.c:1445) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) The buggy address is located 16 bytes inside of allocated 33-byte region [ffff888000554e80, ffff888000554ea1) Kernel panic - not syncing: KASAN: panic_on_warn set ... Cc: stable@vger.kernel.org Fixes: db1312dd9548 ("nvmet: implement basic In-Band Authentication") Reported-by: co+77553a7fc66ac133@bugs.sh Closes: https://lore.kernel.org/all/Ah6QavQXwvshtqyUcYD1P1R7XE0ND9fB7lbV@bugs.sh/ Assisted-by: Codex:gpt-5.6 Signed-off-by: Weiming Shi --- drivers/nvme/target/fabrics-cmd-auth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c index 92f8a76f10..dccdb55a36 100644 --- a/drivers/nvme/target/fabrics-cmd-auth.c +++ b/drivers/nvme/target/fabrics-cmd-auth.c @@ -427,7 +427,7 @@ static int nvmet_auth_challenge(struct nvmet_req *req, void *d, int al) struct nvmet_ctrl *ctrl = req->sq->ctrl; int ret = 0; int hash_len = nvme_auth_hmac_hash_len(ctrl->shash_id); - int data_size = sizeof(*d) + hash_len; + int data_size = sizeof(*data) + hash_len; if (ctrl->dh_tfm) data_size += ctrl->dh_keysize; -- 2.55.0