Re: [PATCH] nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()

[Keith Busch <kbusch@kernel.org>]

On Sun, Sep 13, 2026 at 01:10:11AM +0800, Weiming Shi wrote:
> 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 ...

Thanks, applied to nvme-7.3.