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CVE-2023-52463— efivarfs: force RO when remounting if SetVariable is not supported

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux Kernel 存在安全漏洞，该漏洞源于 efivarfs 模块存在潜在的崩溃问题。

AI Predicted 7.8 Difficulty: Easy EPSS 0.24% · P14

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux f88814cc2578c121e6edef686365036db72af0ed< 94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8 affected
f88814cc2578c121e6edef686365036db72af0ed< 2aa141f8bc580f8f9811dfe4e0e6009812b73826 affected
f88814cc2578c121e6edef686365036db72af0ed< d4a9aa7db574a0da64307729cc031fb68597aa8b affected
f88814cc2578c121e6edef686365036db72af0ed< 0049fe7e4a85849bdd778cdb72e51a791ff3d737 affected
f88814cc2578c121e6edef686365036db72af0ed< d4a714873db0866cc471521114eeac4a5072d548 affected
f88814cc2578c121e6edef686365036db72af0ed< 0e8d2444168dd519fea501599d150e62718ed2fe affected
552952e51fad35670459674bcb8a03bd96fe4646 affected
5.7.11< 5.8 affected
… +8 more rows
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I. Basic Information for CVE-2023-52463

Vulnerability Information
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Vulnerability Title
efivarfs: force RO when remounting if SetVariable is not supported
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: efivarfs: force RO when remounting if SetVariable is not supported If SetVariable at runtime is not supported by the firmware we never assign a callback for that function. At the same time mount the efivarfs as RO so no one can call that. However, we never check the permission flags when someone remounts the filesystem as RW. As a result this leads to a crash looking like this: $ mount -o remount,rw /sys/firmware/efi/efivars $ efi-updatevar -f PK.auth PK [ 303.279166] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 303.280482] Mem abort info: [ 303.280854] ESR = 0x0000000086000004 [ 303.281338] EC = 0x21: IABT (current EL), IL = 32 bits [ 303.282016] SET = 0, FnV = 0 [ 303.282414] EA = 0, S1PTW = 0 [ 303.282821] FSC = 0x04: level 0 translation fault [ 303.283771] user pgtable: 4k pages, 48-bit VAs, pgdp=000000004258c000 [ 303.284913] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 303.286076] Internal error: Oops: 0000000086000004 [#1] PREEMPT SMP [ 303.286936] Modules linked in: qrtr tpm_tis tpm_tis_core crct10dif_ce arm_smccc_trng rng_core drm fuse ip_tables x_tables ipv6 [ 303.288586] CPU: 1 PID: 755 Comm: efi-updatevar Not tainted 6.3.0-rc1-00108-gc7d0c4695c68 #1 [ 303.289748] Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.04-00627-g88336918701d 04/01/2023 [ 303.291150] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 303.292123] pc : 0x0 [ 303.292443] lr : efivar_set_variable_locked+0x74/0xec [ 303.293156] sp : ffff800008673c10 [ 303.293619] x29: ffff800008673c10 x28: ffff0000037e8000 x27: 0000000000000000 [ 303.294592] x26: 0000000000000800 x25: ffff000002467400 x24: 0000000000000027 [ 303.295572] x23: ffffd49ea9832000 x22: ffff0000020c9800 x21: ffff000002467000 [ 303.296566] x20: 0000000000000001 x19: 00000000000007fc x18: 0000000000000000 [ 303.297531] x17: 0000000000000000 x16: 0000000000000000 x15: 0000aaaac807ab54 [ 303.298495] x14: ed37489f673633c0 x13: 71c45c606de13f80 x12: 47464259e219acf4 [ 303.299453] x11: ffff000002af7b01 x10: 0000000000000003 x9 : 0000000000000002 [ 303.300431] x8 : 0000000000000010 x7 : ffffd49ea8973230 x6 : 0000000000a85201 [ 303.301412] x5 : 0000000000000000 x4 : ffff0000020c9800 x3 : 00000000000007fc [ 303.302370] x2 : 0000000000000027 x1 : ffff000002467400 x0 : ffff000002467000 [ 303.303341] Call trace: [ 303.303679] 0x0 [ 303.303938] efivar_entry_set_get_size+0x98/0x16c [ 303.304585] efivarfs_file_write+0xd0/0x1a4 [ 303.305148] vfs_write+0xc4/0x2e4 [ 303.305601] ksys_write+0x70/0x104 [ 303.306073] __arm64_sys_write+0x1c/0x28 [ 303.306622] invoke_syscall+0x48/0x114 [ 303.307156] el0_svc_common.constprop.0+0x44/0xec [ 303.307803] do_el0_svc+0x38/0x98 [ 303.308268] el0_svc+0x2c/0x84 [ 303.308702] el0t_64_sync_handler+0xf4/0x120 [ 303.309293] el0t_64_sync+0x190/0x194 [ 303.309794] Code: ???????? ???????? ???????? ???????? (????????) [ 303.310612] ---[ end trace 0000000000000000 ]--- Fix this by adding a .reconfigure() function to the fs operations which we can use to check the requested flags and deny anything that's not RO if the firmware doesn't implement SetVariable at runtime.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux Kernel 存在安全漏洞，该漏洞源于 efivarfs 模块存在潜在的崩溃问题。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux f88814cc2578c121e6edef686365036db72af0ed ~ 94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8 -
Linux Linux 5.8 -

II. Public POCs for CVE-2023-52463

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III. Intelligence Information for CVE-2023-52463

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Mailing List Discussions for CVE-2023-52463 (1)

Other References for CVE-2023-52463 (6)

Same Patch Batch · Linux · 2024-02-23 · 19 CVEs total

CVE-2024-26594 9.1 CRITICAL ksmbd: validate mech token in session setup
CVE-2024-26598 8.8 HIGH KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
CVE-2024-26597 7.8 HIGH net: qualcomm: rmnet: fix global oob in rmnet_policy
CVE-2023-52461 7.8 HIGH drm/sched: Fix bounds limiting when given a malformed entity
CVE-2023-52454 7.5 HIGH nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length
CVE-2023-52453 7.1 HIGH hisi_acc_vfio_pci: Update migration data pointer correctly on saving/resume
CVE-2023-52459 media: v4l: async: Fix duplicated list deletion
CVE-2024-26593 i2c: i801: Fix block process call transactions
CVE-2023-52455 iommu: Don't reserve 0-length IOVA region
CVE-2023-52456 serial: imx: fix tx statemachine deadlock
CVE-2023-52458 block: add check that partition length needs to be aligned with block size
CVE-2023-52457 serial: 8250: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed
CVE-2023-52460 drm/amd/display: Fix NULL pointer dereference at hibernate
CVE-2023-52462 bpf: fix check for attempt to corrupt spilled pointer
CVE-2023-52464 EDAC/thunderx: Fix possible out-of-bounds string access
CVE-2024-26596 net: dsa: fix netdev_priv() dereference before check on non-DSA netdevice events
CVE-2024-26595 mlxsw: spectrum_acl_tcam: Fix NULL pointer dereference in error path
CVE-2024-26599 pwm: Fix out-of-bounds access in of_pwm_single_xlate()

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2023-52463

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