max_qpairs = ha->msix_count - 1 (MB interrupt) - 1 (default response queue) - 1 (ATIO, in dual or pure target mode) max_qpairs is set to zero in case of two CPUs and initiator mode. The number is then used to allocate ha->queue_pair_map inside qla2x00_alloc_queues(). No allocation happens and ha->queue_pair_map is left NULL but the driver thinks there are queue pairs available. qla2xxx_queuecommand() tries to find a qpair in the map and crashes: if (ha->mqenable) { uint32_t tag; uint16_t hwq; struct qla_qpair *qpair = NULL; tag = blk_mq_unique_tag(cmd->request); hwq = blk_mq_unique_tag_to_hwq(tag); qpair = ha->queue_pair_map[hwq]; # <- HERE if (qpair) return qla2xxx_mqueuecommand(host, cmd, qpair); } BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 72 Comm: kworker/u4:3 Tainted: G W 5.10.0-rc1+ #25 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 Workqueue: scsi_wq_7 fc_scsi_scan_rport [scsi_transport_fc] RIP: 0010:qla2xxx_queuecommand+0x16b/0x3f0 [qla2xxx] Call Trace: scsi_queue_rq+0x58c/0xa60 blk_mq_dispatch_rq_list+0x2b7/0x6f0 ? __sbitmap_get_word+0x2a/0x80 __blk_mq_sched_dispatch_requests+0xb8/0x170 blk_mq_sched_dispatch_requests+0x2b/0x50 __blk_mq_run_hw_queue+0x49/0xb0 __blk_mq_delay_run_hw_queue+0xfb/0x150 blk_mq_sched_insert_request+0xbe/0x110 blk_execute_rq+0x45/0x70 __scsi_execute+0x10e/0x250 scsi_probe_and_add_lun+0x228/0xda0 __scsi_scan_target+0xf4/0x620 ? __pm_runtime_resume+0x4f/0x70 scsi_scan_target+0x100/0x110 fc_scsi_scan_rport+0xa1/0xb0 [scsi_transport_fc] process_one_work+0x1ea/0x3b0 worker_thread+0x28/0x3b0 ? process_one_work+0x3b0/0x3b0 kthread+0x112/0x130 ? kthread_park+0x80/0x80 ret_from_fork+0x22/0x30 The driver should allocate enough vectors to provide every CPU it's own HW queue and still handle reserved (MB, RSP, ATIO) interrupts. The change fixes the crash on dual core VM and prevents unbalanced QP allocation where nr_hw_queues is two less than the number of CPUs.">
Weakness Name | Source | |
---|---|---|
NULL Pointer Dereference The product dereferences a pointer that it expects to be valid but is NULL. |
Metrics | Score | Severity | CVSS Vector | Source |
---|---|---|---|---|
V3.1 | 5.5 | MEDIUM |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
More informations
Base: Exploitabilty MetricsThe Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. Local The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Attack Complexity This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Low Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. Low The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources. User Interaction This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component. None The vulnerable system can be exploited without interaction from any user. Base: Scope MetricsThe Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope. Scope Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs. Unchanged An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority. Base: Impact MetricsThe Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. None There is no loss of confidentiality within the impacted component. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. None There is no loss of integrity within the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. High There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable). Temporal MetricsThe Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability. Environmental MetricsThese metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability. |
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