CVE-2022-49476

Description

From CVE.org

In the Linux kernel, the following vulnerability has been resolved: mt76: mt7921: fix kernel crash at mt7921_pci_remove The crash log shown it is possible that mt7921_irq_handler is called while devm_free_irq is being handled so mt76_free_device need to be postponed until devm_free_irq is completed to solve the crash we free the mt76 device too early. [ 9299.339655] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 9299.339705] #PF: supervisor read access in kernel mode [ 9299.339735] #PF: error_code(0x0000) - not-present page [ 9299.339768] PGD 0 P4D 0 [ 9299.339786] Oops: 0000 [#1] SMP PTI [ 9299.339812] CPU: 1 PID: 1624 Comm: prepare-suspend Not tainted 5.15.14-1.fc32.qubes.x86_64 #1 [ 9299.339863] Hardware name: Xen HVM domU, BIOS 4.14.3 01/20/2022 [ 9299.339901] RIP: 0010:mt7921_irq_handler+0x1e/0x70 [mt7921e] [ 9299.340048] RSP: 0018:ffffa81b80c27cb0 EFLAGS: 00010082 [ 9299.340081] RAX: 0000000000000000 RBX: ffff98a4cb752020 RCX: ffffffffa96211c5 [ 9299.340123] RDX: 0000000000000000 RSI: 00000000000d4204 RDI: ffff98a4cb752020 [ 9299.340165] RBP: ffff98a4c28a62a4 R08: ffff98a4c37a96c0 R09: 0000000080150011 [ 9299.340207] R10: 0000000040000000 R11: 0000000000000000 R12: ffff98a4c4eaa080 [ 9299.340249] R13: ffff98a4c28a6360 R14: ffff98a4cb752020 R15: ffff98a4c28a6228 [ 9299.340297] FS: 00007260840d3740(0000) GS:ffff98a4ef700000(0000) knlGS:0000000000000000 [ 9299.340345] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9299.340383] CR2: 0000000000000008 CR3: 0000000004c56001 CR4: 0000000000770ee0 [ 9299.340432] PKRU: 55555554 [ 9299.340449] Call Trace: [ 9299.340467] <TASK> [ 9299.340485] __free_irq+0x221/0x350 [ 9299.340527] free_irq+0x30/0x70 [ 9299.340553] devm_free_irq+0x55/0x80 [ 9299.340579] mt7921_pci_remove+0x2f/0x40 [mt7921e] [ 9299.340616] pci_device_remove+0x3b/0xa0 [ 9299.340651] __device_release_driver+0x17a/0x240 [ 9299.340686] device_driver_detach+0x3c/0xa0 [ 9299.340714] unbind_store+0x113/0x130 [ 9299.340740] kernfs_fop_write_iter+0x124/0x1b0 [ 9299.340775] new_sync_write+0x15c/0x1f0 [ 9299.340806] vfs_write+0x1d2/0x270 [ 9299.340831] ksys_write+0x67/0xe0 [ 9299.340857] do_syscall_64+0x3b/0x90 [ 9299.340887] entry_SYSCALL_64_after_hwframe+0x44/0xae

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).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score5.55.55.5
Attack VectorLocalLocalLocal
Attack ComplexityLowLowLow
Privileges RequiredLowLowLow
User InteractionNoneNoneNone
ScopeUnchangedUnchangedUnchanged
ConfidentialityNoneNoneNone
Integrity ImpactNoneNoneNone
Availability ImpactHighHighHigh

Vector

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

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

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

Understanding the Weakness (CWE)

CWE-476

Availability

Technical Impact: DoS: Crash, Exit, or Restart

NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.

Integrity,Confidentiality

Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory

In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.

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