scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show() If the allocation of tl_hba->sh fails in tcm_loop_driver_probe() and we attempt to dereference it in tcm_loop_tpg_address_show() we will get a segfault, see below for an example. So, check tl_hba->sh before dereferencing it. Unable to allocate struct scsi_host BUG: kernel NULL pointer dereference, address: 0000000000000194 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 8356 Comm: tokio-runtime-w Not tainted 6.6.104.2-4.azl3 #1 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/28/2024 RIP: 0010:tcm_loop_tpg_address_show+0x2e/0x50 [tcm_loop] ... Call Trace: <TASK> configfs_read_iter+0x12d/0x1d0 [configfs] vfs_read+0x1b5/0x300 ksys_read+0x6f/0xf0 ...

References

• https://git.kernel.org/stable/c/63f511d3855f7f4b35dd63dbc58fc3d935a81268
• https://git.kernel.org/stable/c/3d8c517f6eb27e47b1a198e05f8023038329b40b
• https://git.kernel.org/stable/c/f449a1edd7a13bb025aaf9342ea6f8bf92684bbf
• https://git.kernel.org/stable/c/1c9ba455b5073253ceaadae4859546e38e8261fe
• https://git.kernel.org/stable/c/a6ef60898ddaf1414592ce3e5b0d94276d631663
• https://git.kernel.org/stable/c/72e8831079266749a7023618a0de2f289a9dced6
• https://git.kernel.org/stable/c/13aff3b8a7184281b134698704d6c06863a8361b
• https://git.kernel.org/stable/c/e6965188f84a7883e6a0d3448e86b0cf29b24dfc