CVE-2025-22089: linux kernel vulnerability

What is known

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Don't expose hw_counters outside of init net namespace Commit 467f432a521a ("RDMA/core: Split port and device counter sysfs attributes") accidentally almost exposed hw counters to non-init net namespaces. It didn't expose them fully, as an attempt to read any of those counters leads to a crash like this one: [42021.807566] BUG: kernel NULL pointer dereference, address: 0000000000000028 [42021.814463] #PF: supervisor read access in kernel mode [42021.819549] #PF: error_code(0x0000) - not-present page [42021.824636] PGD 0 P4D 0 [42021.827145] Oops: 0000 [#1] SMP PTI [42021.830598] CPU: 82 PID: 2843922 Comm: switchto-defaul Kdump: loaded Tainted: G S W I XXX [42021.841697] Hardware name: XXX [42021.849619] RIP: 0010:hw_stat_device_show+0x1e/0x40 [ib_core] [42021.855362] Code: 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 49 89 d0 4c 8b 5e 20 48 8b 8f b8 04 00 00 48 81 c7 f0 fa ff ff <48> 8b 41 28 48 29 ce 48 83 c6 d0 48 c1 ee 04 69 d6 ab aa aa aa 48 [42021.873931] RSP: 0018:ffff97fe90f03da0 EFLAGS: 00010287 [42021.879108] RAX: ffff9406988a8c60 RBX: ffff940e1072d438 RCX: 0000000000000000 [42021.886169] RDX: ffff94085f1aa000 RSI: ffff93c6cbbdbcb0 RDI: ffff940c7517aef0 [42021.893230] RBP: ffff97fe90f03e70 R08: ffff94085f1aa000 R09: 0000000000000000 [42021.900294] R10: ffff94085f1aa000 R11: ffffffffc0775680 R12: ffffffff87ca2530 [42021.907355] R13: ffff940651602840 R14: ffff93c6cbbdbcb0 R15: ffff94085f1aa000 [42021.914418] FS: 00007fda1a3b9700(0000) GS:ffff94453fb80000(0000) knlGS:0000000000000000 [42021.922423] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [42021.928130] CR2: 0000000000000028 CR3: 00000042dcfb8003 CR4: 00000000003726f0 [42021.935194] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [42021.942257] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [42021.949324] Call Trace: [42021.951756] <TASK> [42021.953842] [<ffffffff86c58674>] ? show_regs+0x64/0x70 [42021.959030] [<ffffffff86c58468>] ? __die+0x78/0xc0 [42021.963874] [<ffffffff86c9ef75>] ? page_fault_oops+0x2b5/0x3b0 [42021.969749] [<ffffffff87674b92>] ? exc_page_fault+0x1a2/0x3c0 [42021.975549] [<ffffffff87801326>] ? asm_exc_page_fault+0x26/0x30 [42021.981517] [<ffffffffc0775680>] ? __pfx_show_hw_stats+0x10/0x10 [ib_core] [42021.988482] [<ffffffffc077564e>] ? hw_stat_device_show+0x1e/0x40 [ib_core] [42021.995438] [<ffffffff86ac7f8e>] dev_attr_show+0x1e/0x50 [42022.000803] [<ffffffff86a3eeb1>] sysfs_kf_seq_show+0x81/0xe0 [42022.006508] [<ffffffff86a11134>] seq_read_iter+0xf4/0x410 [42022.011954] [<ffffffff869f4b2e>] vfs_read+0x16e/0x2f0 [42022.017058] [<ffffffff869f50ee>] ksys_read+0x6e/0xe0 [42022.022073] [<ffffffff8766f1ca>] do_syscall_64+0x6a/0xa0 [42022.027441] [<ffffffff8780013b>] entry_SYSCALL_64_after_hwframe+0x78/0xe2 The problem can be reproduced using the following steps: ip netns add foo ip netns exec foo bash cat /sys/class/infiniband/mlx4_0/hw_counters/* The panic occurs because of casting the device pointer into an ib_device pointer using container_of() in hw_stat_device_show() is wrong and leads to a memory corruption. However the real problem is that hw counters should never been exposed outside of the non-init net namespace. Fix this by saving the index of the corresponding attribute group (it might be 1 or 2 depending on the presence of driver-specific attributes) and zeroing the pointer to hw_counters group for compat devices during the initialization. With this fix applied hw_counters are not available in a non-init net namespace: find /sys/class/infiniband/mlx4_0/ -name hw_counters /sys/class/infiniband/mlx4_0/ports/1/hw_counters /sys/class/infiniband/mlx4_0/ports/2/hw_counters /sys/class/infiniband/mlx4_0/hw_counters ip netns add foo ip netns exec foo bash find /sys/class/infiniband/mlx4_0/ -name hw_counters

Business impact

Successful exploitation of CVE-2025-22089, a high vulnerability (CVSS 7.8) affecting linux kernel, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether linux kernel is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

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