Affected: Linux

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

scsi: target: Bound PR-OUT TransportID parsing to the received buffer

core_scsi3_decode_spec_i_port() and core_scsi3_emulate_register_and_move() hand the raw PERSISTENT RESERVE OUT parameter buffer to target_parse_pr_out_transport_id() without telling it how many bytes are valid. For an iSCSI TransportID (FORMAT CODE 01b), iscsi_parse_pr_out_transport_id() locates the ",i,0x" ISID separator with an unbounded strstr() (and on the error path prints the name with a further unbounded "%s"). An initiator can submit a TransportID whose iSCSI name contains neither a ",i,0x" substring nor a NUL terminator, filling the parameter list to its end, so the scan runs off the end of the buffer.

When the parameter list spans more than one page the buffer is a multi-page vmap (transport_kmap_data_sg()), so the over-read walks into the trailing vmalloc guard page and oopses (KASAN: vmalloc-out-of-bounds in strstr). It is reachable by any fabric that delivers a PR OUT to a device exported through an iSCSI TPG, including a guest via vhost-scsi.

Pass the number of received bytes down to the parser and validate the iSCSI TransportID's own self-described length (ADDITIONAL LENGTH + 4) once, up front: reject it if it is below the spc4r17 minimum or larger than the received buffer, then bound the separator search, the ISID walk and the name copy by that length. This is the length check the callers already perform after the p…