CVE-2022-50002

Description

From CVE.org

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: LAG, fix logic over MLX5_LAG_FLAG_NDEVS_READY Only set MLX5_LAG_FLAG_NDEVS_READY if both netdevices are registered. Doing so guarantees that both ldev->pf[MLX5_LAG_P0].dev and ldev->pf[MLX5_LAG_P1].dev have valid pointers when MLX5_LAG_FLAG_NDEVS_READY is set. The core issue is asymmetry in setting MLX5_LAG_FLAG_NDEVS_READY and clearing it. Setting it is done wrongly when both ldev->pf[MLX5_LAG_P0].dev and ldev->pf[MLX5_LAG_P1].dev are set; clearing it is done right when either of ldev->pf[i].netdev is cleared. Consider the following scenario: 1. PF0 loads and sets ldev->pf[MLX5_LAG_P0].dev to a valid pointer 2. PF1 loads and sets both ldev->pf[MLX5_LAG_P1].dev and ldev->pf[MLX5_LAG_P1].netdev with valid pointers. This results in MLX5_LAG_FLAG_NDEVS_READY is set. 3. PF0 is unloaded before setting dev->pf[MLX5_LAG_P0].netdev. MLX5_LAG_FLAG_NDEVS_READY remains set. Further execution of mlx5_do_bond() will result in null pointer dereference when calling mlx5_lag_is_multipath() This patch fixes the following call trace actually encountered: [ 1293.475195] BUG: kernel NULL pointer dereference, address: 00000000000009a8 [ 1293.478756] #PF: supervisor read access in kernel mode [ 1293.481320] #PF: error_code(0x0000) - not-present page [ 1293.483686] PGD 0 P4D 0 [ 1293.484434] Oops: 0000 [#1] SMP PTI [ 1293.485377] CPU: 1 PID: 23690 Comm: kworker/u16:2 Not tainted 5.18.0-rc5_for_upstream_min_debug_2022_05_05_10_13 #1 [ 1293.488039] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1293.490836] Workqueue: mlx5_lag mlx5_do_bond_work [mlx5_core] [ 1293.492448] RIP: 0010:mlx5_lag_is_multipath+0x5/0x50 [mlx5_core] [ 1293.494044] Code: e8 70 40 ff e0 48 8b 14 24 48 83 05 5c 1a 1b 00 01 e9 19 ff ff ff 48 83 05 47 1a 1b 00 01 eb d7 0f 1f 44 00 00 0f 1f 44 00 00 <48> 8b 87 a8 09 00 00 48 85 c0 74 26 48 83 05 a7 1b 1b 00 01 41 b8 [ 1293.498673] RSP: 0018:ffff88811b2fbe40 EFLAGS: 00010202 [ 1293.500152] RAX: ffff88818a94e1c0 RBX: ffff888165eca6c0 RCX: 0000000000000000 [ 1293.501841] RDX: 0000000000000001 RSI: ffff88818a94e1c0 RDI: 0000000000000000 [ 1293.503585] RBP: 0000000000000000 R08: ffff888119886740 R09: ffff888165eca73c [ 1293.505286] R10: 0000000000000018 R11: 0000000000000018 R12: ffff88818a94e1c0 [ 1293.506979] R13: ffff888112729800 R14: 0000000000000000 R15: ffff888112729858 [ 1293.508753] FS: 0000000000000000(0000) GS:ffff88852cc40000(0000) knlGS:0000000000000000 [ 1293.510782] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1293.512265] CR2: 00000000000009a8 CR3: 00000001032d4002 CR4: 0000000000370ea0 [ 1293.514001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1293.515806] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score5.35.5N/A
Attack VectorLocalLocalN/A
Attack ComplexityHighLowN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityNoneNoneN/A
Integrity ImpactLowNoneN/A
Availability ImpactHighHighN/A

Vector

Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H

NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Understanding the Weakness (CWE)

CWE-821

Integrity,Confidentiality,Other

Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic

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