From: Bryam Vargas Date: Wed, 10 Jun 2026 04:22:48 +0000 (+0000) Subject: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE X-Git-Tag: v7.2-rc4~9^2~4 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fda6a1f3c3d7047b5ce5654487649c2daa738bfc;p=thirdparty%2Fkernel%2Flinux.git 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. Fixes: 4949314c7283 ("target: Allow control CDBs with data > 1 page") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Reviewed-by: John Garry Reviewed-by: David Disseldorp Link: https://patch.msgid.link/20260610042245.35473-1-hexlabsecurity@proton.me Signed-off-by: Martin K. Petersen --- diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c index 0b19997c2edd..1a77b4bb62b0 100644 --- a/drivers/target/target_core_pr.c +++ b/drivers/target/target_core_pr.c @@ -3293,9 +3293,6 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key, goto out; } - transport_kunmap_data_sg(cmd); - buf = NULL; - pr_debug("SPC-3 PR [%s] Extracted initiator %s identifier: %s" " %s\n", dest_tf_ops->fabric_name, (iport_ptr != NULL) ? "port" : "device", initiator_str, (iport_ptr != NULL) ? @@ -3532,6 +3529,11 @@ after_iport_check: core_scsi3_update_and_write_aptpl(cmd->se_dev, aptpl); core_scsi3_put_pr_reg(dest_pr_reg); + /* + * iport_ptr aliases the PR-OUT parameter list mapped above, so the + * buffer is unmapped only here on success (and at out: on error). + */ + transport_kunmap_data_sg(cmd); return 0; out: if (buf)