Affected: Linux

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

scsi: libiscsi: Validate the task named by a management response

__iscsi_complete_pdu() fetches the task for five response types from one place and checks only that the index resolved:

case ISCSI_OP_LOGOUT_RSP: case ISCSI_OP_LOGIN_RSP: case ISCSI_OP_TEXT_RSP: case ISCSI_OP_SCSI_TMFUNC_RSP: case ISCSI_OP_NOOP_IN: task = iscsi_itt_to_task(conn, hdr->itt); if (!task) return ISCSI_ERR_BAD_ITT;

iscsi_itt_to_task() bounds the index against cmds_max and looks at nothing else, so a target can name any slot in the pool, including one that has never been used. task->conn is then NULL, and both iscsi_nop_out_rsp() and iscsi_complete_task() dereference it. One unsolicited NOP-In is enough; a Text Response carrying the same ITT crashes in iscsi_complete_task() instead.

Require the task to be in flight and not a SCSI command, the way iscsi_itt_to_ctask() does for the command opcodes.

[ 6.298634] Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI [ 6.298642] KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] [ 6.298652] CPU: 1 UID: 0 PID: 111 Comm: iscsistart Not tainted 7.2.0-rc5-ISCSI1-gf5098b6bae76 #1 PREEMPT(lazy) [ 6.298654] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 […