CVE-2026-72083scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE

Official description

In the Linux kernel, the following vulnerability has been resolved: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE core_scsi3_emulate_pro_register_and_move() maps the PERSISTENT RESERVE OUT parameter list with transport_kmap_data_sg() and parses the destination TransportID with target_parse_pr_out_transport_id(). For an iSCSI TransportID (FORMAT CODE 01b), iscsi_parse_pr_out_transport_id() returns the ISID in iport_ptr as a raw pointer into that mapped buffer. The function then unmaps the buffer with transport_kunmap_data_sg() before dereferencing iport_ptr in strcmp(), __core_scsi3_locate_pr_reg() and core_scsi3_alloc_registration(). When the parameter list spans more than one page (PARAMETER LIST LENGTH > 4096), transport_kmap_data_sg() uses vmap() and transport_kunmap_data_sg() does vunmap(), so the kernel virtual address backing iport_ptr is torn down and every subsequent dereference is a use-after-free read of the unmapped region. Keep the parameter list mapped until iport_ptr is no longer needed: drop the early transport_kunmap_data_sg() and unmap once on the success path, right before returning. The error paths already unmap through the existing "if (buf) transport_kunmap_data_sg(cmd)" at the out: label, which now runs on every post-map error exit because buf is no longer cleared early. Only reads of the mapping happen while spinlocks are held; the map and unmap calls remain outside any lock. The sibling caller core_scsi3_decode_spec_i_port() already uses the buffer before unmapping it and is left unchanged.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/7d56f5c868d92c9d504a34a3ea450bce481c7f63
• https://git.kernel.org/stable/c/59a2a5a37dc49a641ad6bc64aee34e5a61025ffd
• https://git.kernel.org/stable/c/9f8076cc73dfa6b10155978c160587e986b22169
• https://git.kernel.org/stable/c/a040004846f1fbe687f6ec76d9ccc27b4ead42e4
• https://git.kernel.org/stable/c/05b3e37433cf2eaf8867f1c16528aa347bb212ab
• https://git.kernel.org/stable/c/cb7bdae7fba404852ade34b0c1445fbaf3e54fbb
• https://git.kernel.org/stable/c/ef2ee18fec92088c7d8877baf7674e89389ccd66
• https://git.kernel.org/stable/c/fda6a1f3c3d7047b5ce5654487649c2daa738bfc