CVE-2025-38209

In the Linux kernel, the following vulnerability has been resolved:

nvme-tcp: remove tag set when second admin queue config fails

Commit 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure

concatenation") modified nvme_tcp_setup_ctrl() to call

nvme_tcp_configure_admin_queue() twice. The first call prepares for

DH-CHAP negotitation, and the second call is required for secure

concatenation. However, this change triggered BUG KASAN slab-use-after-

free in blk_mq_queue_tag_busy_iter(). This BUG can be recreated by

repeating the blktests test case nvme/063 a few times [1].

When the BUG happens, nvme_tcp_create_ctrl() fails in the call chain

below:

nvme_tcp_create_ctrl()

nvme_tcp_alloc_ctrl() new=true ... Alloc nvme_tcp_ctrl and admin_tag_set

nvme_tcp_setup_ctrl() new=true

nvme_tcp_configure_admin_queue() new=true ... Succeed

nvme_alloc_admin_tag_set() ... Alloc the tag set for admin_tag_set

nvme_stop_keep_alive()

nvme_tcp_teardown_admin_queue() remove=false

nvme_tcp_configure_admin_queue() new=false

nvme_tcp_alloc_admin_queue() ... Fail, but do not call nvme_remove_admin_tag_set()

nvme_uninit_ctrl()

nvme_put_ctrl() ... Free up the nvme_tcp_ctrl and admin_tag_set

The first call of nvme_tcp_configure_admin_queue() succeeds with

new=true argument. The second call fails with new=false argument. This

second call does not call nvme_remove_admin_tag_set() on failure, due to

the new=false argument. Then the admin tag set is not removed. However,

nvme_tcp_create_ctrl() assumes that nvme_tcp_setup_ctrl() would call

nvme_remove_admin_tag_set(). Then it frees up struct nvme_tcp_ctrl which

has admin_tag_set field. Later on, the timeout handler accesses the

admin_tag_set field and causes the BUG KASAN slab-use-after-free.

To not leave the admin tag set, call nvme_remove_admin_tag_set() when

the second nvme_tcp_configure_admin_queue() call fails. Do not return

from nvme_tcp_setup_ctrl() on failure. Instead, jump to "destroy_admin"

go-to label to call nvme_tcp_teardown_admin_queue() which calls

nvme_remove_admin_tag_set().