CVE-2024-35907: Vulnerability in Linux Linux

Severity: highType: vulnerabilityCVE-2024-35907

In the Linux kernel, the following vulnerability has been resolved: mlxbf_gige: call request_irq() after NAPI initialized The mlxbf_gige driver encounters a NULL pointer exception in mlxbf_gige_open() when kdump is enabled. The sequence to reproduce the exception is as follows: a) enable kdump b) trigger kdump via "echo c > /proc/sysrq-trigger" c) kdump kernel executes d) kdump kernel loads mlxbf_gige module e) the mlxbf_gige module runs its open() as the the "oob_net0" interface is brought up f) mlxbf_gige module will experience an exception during its open(), something like: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000086000004 EC = 0x21: IABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000086000004 [#1] SMP CPU: 0 PID: 812 Comm: NetworkManager Tainted: G OE 5.15.0-1035-bluefield #37-Ubuntu Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : 0x0 lr : __napi_poll+0x40/0x230 sp : ffff800008003e00 x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8 x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000 x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000 x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0 x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398 x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2 x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238 Call trace: 0x0 net_rx_action+0x178/0x360 __do_softirq+0x15c/0x428 __irq_exit_rcu+0xac/0xec irq_exit+0x18/0x2c handle_domain_irq+0x6c/0xa0 gic_handle_irq+0xec/0x1b0 call_on_irq_stack+0x20/0x2c do_interrupt_handler+0x5c/0x70 el1_interrupt+0x30/0x50 el1h_64_irq_handler+0x18/0x2c el1h_64_irq+0x7c/0x80 __setup_irq+0x4c0/0x950 request_threaded_irq+0xf4/0x1bc mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige] mlxbf_gige_open+0x5c/0x170 [mlxbf_gige] __dev_open+0x100/0x220 __dev_change_flags+0x16c/0x1f0 dev_change_flags+0x2c/0x70 do_setlink+0x220/0xa40 __rtnl_newlink+0x56c/0x8a0 rtnl_newlink+0x58/0x84 rtnetlink_rcv_msg+0x138/0x3c4 netlink_rcv_skb+0x64/0x130 rtnetlink_rcv+0x20/0x30 netlink_unicast+0x2ec/0x360 netlink_sendmsg+0x278/0x490 __sock_sendmsg+0x5c/0x6c ____sys_sendmsg+0x290/0x2d4 ___sys_sendmsg+0x84/0xd0 __sys_sendmsg+0x70/0xd0 __arm64_sys_sendmsg+0x2c/0x40 invoke_syscall+0x78/0x100 el0_svc_common.constprop.0+0x54/0x184 do_el0_svc+0x30/0xac el0_svc+0x48/0x160 el0t_64_sync_handler+0xa4/0x12c el0t_64_sync+0x1a4/0x1a8 Code: bad PC value ---[ end trace 7d1c3f3bf9d81885 ]--- Kernel panic - not syncing: Oops: Fatal exception in interrupt Kernel Offset: 0x2870a7a00000 from 0xffff800008000000 PHYS_OFFSET: 0x80000000 CPU features: 0x0,000005c1,a3332a5a Memory Limit: none ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]--- The exception happens because there is a pending RX interrupt before the call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires immediately after this request_irq() completes. The ---truncated---

AI Analysis

Technical Summary

CVE-2024-35907 is a vulnerability in the Linux kernel specifically affecting the mlxbf_gige network driver used in Mellanox BlueField-3 SmartNIC hardware. The issue arises due to improper ordering of interrupt request initialization in the driver. When the kdump kernel crash dump mechanism is enabled and triggered, the mlxbf_gige module is loaded and attempts to bring up the "oob_net0" network interface. During this process, the driver calls request_irq() to register the RX interrupt handler after the NAPI (New API) polling mechanism has been initialized. However, a pending RX interrupt can fire immediately after request_irq() completes, before the driver is fully ready to handle it. This leads to a NULL pointer dereference in the mlxbf_gige_open() function, causing a kernel oops and subsequent kernel panic. The panic results in a denial of service (DoS) condition, crashing the kernel and potentially disrupting network connectivity and system availability. The vulnerability is triggered in a very specific scenario involving kdump and the BlueField-3 SmartNIC hardware, which is used in high-performance computing and data center environments. The root cause is a race condition between interrupt handling and driver initialization, which has been resolved by correcting the order of request_irq() calls after NAPI setup. No known exploits are reported in the wild yet, and the vulnerability does not have an assigned CVSS score. The impact is primarily on system stability and availability during crash dump operations on affected hardware configurations running vulnerable Linux kernel versions.

Potential Impact

For European organizations, especially those operating data centers, cloud infrastructure, or high-performance computing environments utilizing Mellanox BlueField-3 SmartNICs, this vulnerability poses a risk of kernel panics and system crashes during kdump-triggered crash dump operations. This can lead to unexpected downtime, loss of network connectivity, and disruption of critical services. Organizations relying on automated crash dump mechanisms for post-mortem analysis may find their diagnostics hindered, complicating incident response. The impact is more pronounced in environments where kdump is enabled and actively used for kernel crash analysis. While the vulnerability does not allow remote code execution or privilege escalation, the denial of service effect can affect availability and operational continuity. Given the specialized hardware involved, the threat is limited to organizations deploying BlueField-3 SmartNICs, which are common in advanced networking and storage solutions. European enterprises in sectors such as telecommunications, cloud service providers, financial services, and research institutions using this hardware should be particularly vigilant.

Mitigation Recommendations

1. Apply the official Linux kernel patches that reorder the request_irq() call to occur after NAPI initialization, as provided by the Linux kernel maintainers or your Linux distribution vendor. 2. If patching is not immediately possible, consider disabling kdump temporarily to avoid triggering the vulnerability during kernel crash dump operations. 3. Monitor kernel logs for signs of NULL pointer dereferences or kernel panics related to mlxbf_gige during network interface initialization. 4. Validate and update firmware and drivers for BlueField-3 SmartNICs to the latest versions recommended by Mellanox/NVIDIA, as hardware vendor updates may include relevant fixes. 5. Implement robust system monitoring and automated recovery mechanisms to minimize downtime in case of kernel panics. 6. Test kernel updates and patches in staging environments that replicate production hardware configurations to ensure stability before deployment. 7. Coordinate with hardware and OS vendors to receive timely security advisories and updates related to this vulnerability.