Bug 2546408 (CVE-2026-98358)

Summary:	CVE-2026-98358 kernel: IB/iser: reject a remote invalidation of an unregistered direction
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's iSCSI Extensions for Remote Direct Memory Access (iSER) driver. A remote storage target can trigger a Denial of Service (DoS) by sending an unexpected remote invalidation response for write operations transmitted as immediate data. In this scenario, the initiator driver attempts to access an unregistered memory descriptor, resulting in a null pointer dereference and a kernel crash.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-06 09:16:04 UTC

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

IB/iser: reject a remote invalidation of an unregistered direction

A write command whose data is sent entirely as immediate data is not
registered.  iser_reg_mem_fastreg() takes the DMA key path and leaves
rdma_reg[ISER_DIR_OUT].desc at NULL, while iser_dma_map_task_data() has
already set dir[ISER_DIR_OUT].

iser_check_remote_inv() looks at dir[] alone and hands the descriptor to
iser_inv_desc(), which reads desc->sig_protected.  A target that answers
such a command with IB_WR_SEND_WITH_INV faults the initiator.
Leaving those commands unregistered is deliberate.

The same function already terminates the connection when a target sends
a remote invalidation the initiator did not ask for.  A target that
invalidates a direction that was never registered is in the same class,
so give it the same answer.

  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
  CPU: 0 UID: 0 PID: 40 Comm: kworker/u8:2 Not tainted 7.2.0-rc5-ISERHOST-gf5098b6bae76-dirty #3 PREEMPT(lazy)
  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
  Workqueue: rxe_wq do_work
  RIP: 0010:iser_task_rsp+0x6d6/0xec0
  Code: 48 c1 ea 03 80 3c 02 00 0f 85 ba 06 00 00 48 8b 9b 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 20 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 76 06 00 00 80 7b 20 00 0f 84 3d 04
  RSP: 0018:ffff88811b008db8 EFLAGS: 00010202
  RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000001848
  RDX: 0000000000000004 RSI: 1ffff11021587b12 RDI: 0000000000000020
  RBP: ffff88810adc1ae4 R08: ffff888109b7f860 R09: ffffffff90a922c0
  R10: ffff88810adc1a1c R11: 000000000000003c R12: ffff888109b7f800
  R13: ffff88810adc1acc R14: ffff888109b7f820 R15: 0000000000000000
  FS:  0000000000000000(0000) GS:ffff88818a676000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000005afe2b CR3: 000000010af23005 CR4: 0000000000770ef0
  PKRU: 55555554
  Call Trace:
   <IRQ>
   __ib_process_cq+0xe1/0x390
   ib_poll_handler+0x6e/0x200
   irq_poll_softirq+0x1df/0x480
   ? clockevents_program_event+0x2ba/0x860
   ? __pfx_irq_poll_softirq+0x10/0x10
   handle_softirqs+0x18e/0x590
   ? __pfx_handle_softirqs+0x10/0x10
   ? __hrtimer_rearm_deferred+0x156/0x450
   do_softirq+0x3b/0x60
   </IRQ>
   <TASK>
   __local_bh_enable_ip+0x61/0x70
   __alloc_skb+0x732/0x890
   ? _raw_spin_lock_irqsave+0x85/0xe0
   ? __pfx___alloc_skb+0x10/0x10
   ? _raw_read_unlock_irqrestore+0x16/0x50
   rxe_init_packet+0x16b/0x4f0
   prepare_ack_packet+0xb8/0x830
   rxe_receiver+0x499/0x9980
   ? __pfx_rxe_receiver+0x10/0x10
   ? rxe_completer+0x29e5/0x38c0
   ? hrtimer_start_range_ns_common+0x75f/0x1730
   ? hrtimer_start_range_ns+0xa6/0x2c0
   ? __pfx__raw_spin_lock_irqsave+0x10/0x10
   ? __pfx_rxe_receiver+0x10/0x10
   do_work+0x144/0x470
   process_one_work+0x633/0x1030
   ? assign_work+0x11d/0x370
   worker_thread+0x45b/0xd10
   ? __pfx_worker_thread+0x10/0x10
   kthread+0x2c6/0x3b0
   ? recalc_sigpending+0x15c/0x1e0
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x36e/0x5a0
   ? __pfx_ret_from_fork+0x10/0x10
   ? __switch_to+0x572/0xdd0
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>
  Modules linked in:
  ---[ end trace 0000000000000000 ]---

Comment 1 gkamathe 2026-10-07 07:49:21 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98358.mbox