CVE-2026-99152: scsi: libiscsi: Validate the task named by a management response

CVE-2026-99152: scsi: libiscsi: Validate the task named by a management response

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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
[    6.298656] RIP: 0010:iscsi_nop_out_rsp.constprop.0+0x46/0x160
[    6.298691] Code: c1 ea 03 48 83 ec 08 80 3c 02 00 0f 85 f5 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 58 48 8d 7d 60 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c0 00 00 00 48 8b 45 60 48 39 c3 74 50 48 b8 00
[    6.298698] RSP: 0018:ffff88806c907be8 EFLAGS: 00010206
[    6.298701] RAX: dffffc0000000000 RBX: ffff888006116800 RCX: 0000000000000020
[    6.298702] RDX: 000000000000000c RSI: ffff88800525d578 RDI: 0000000000000060
[    6.298703] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[    6.298706] R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000
[    6.298706] R13: 000000000000002e R14: ffff8880056eb440 R15: ffff888006116800
[    6.298707] FS:  00007fc02d1c2740(0000) GS:ffff8880b29bc000(0000) knlGS:0000000000000000
[    6.298710] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    6.298711] CR2: 000055fe3b56ddf8 CR3: 00000000053b9004 CR4: 0000000000770ef0
[    6.298712] PKRU: 55555554
[    6.298713] Call Trace:
[    6.298714]  <IRQ>
[    6.298714]  __iscsi_complete_pdu+0x13a8/0x22a0
[    6.298758]  iscsi_complete_pdu+0x54/0xa0
[    6.298759]  iscsi_tcp_hdr_recv_done+0x870/0x2c80
[    6.298778]  iscsi_tcp_recv_skb+0x31e/0xec0
[    6.298800]  iscsi_sw_tcp_recv+0x12f/0x390
[    6.298804]  __tcp_read_sock+0x1ab/0x810
[    6.298812]  iscsi_sw_tcp_data_ready+0x18b/0x510
[    6.298814]  tcp_rcv_established+0x1f56/0x3a00
[    6.298842]  tcp_v4_do_rcv+0x449/0x960
[    6.298847]  tcp_v4_rcv+0x2245/0x3bc0

The Linux kernel CVE team has assigned CVE-2026-99152 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.18 with commit 7996a778ff8c717cb1a7a294475c59cc8f1e9fb8 and fixed in 6.18.59 with commit 55a65ef61e2775aeb18fda63bd1959fa8b41f936
	Issue introduced in 2.6.18 with commit 7996a778ff8c717cb1a7a294475c59cc8f1e9fb8 and fixed in 7.2.13 with commit f721487523d45941aed4b0ac8d829b0461a7d860
	Issue introduced in 2.6.18 with commit 7996a778ff8c717cb1a7a294475c59cc8f1e9fb8 and fixed in 7.3 with commit 11bffcd9cb346732eab2914ef44fe777a3f0b585

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-99152
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/scsi/libiscsi.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/55a65ef61e2775aeb18fda63bd1959fa8b41f936
	https://git.kernel.org/stable/c/f721487523d45941aed4b0ac8d829b0461a7d860
	https://git.kernel.org/stable/c/11bffcd9cb346732eab2914ef44fe777a3f0b585