CVE-2023-53487
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-01

Last updated on: 2025-10-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: powerpc/rtas_flash: allow user copy to flash block cache objects With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the /proc/powerpc/rtas/firmware_update interface to prepare a system firmware update yields a BUG(): kernel BUG at mm/usercopy.c:102! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2 Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries NIP: c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000 REGS: c0000000148c76a0 TRAP: 0700 Not tainted (6.5.0-rc3+) MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002242 XER: 0000000c CFAR: c0000000001fbd34 IRQMASK: 0 [ ... GPRs omitted ... ] NIP usercopy_abort+0xa0/0xb0 LR usercopy_abort+0x9c/0xb0 Call Trace: usercopy_abort+0x9c/0xb0 (unreliable) __check_heap_object+0x1b4/0x1d0 __check_object_size+0x2d0/0x380 rtas_flash_write+0xe4/0x250 proc_reg_write+0xfc/0x160 vfs_write+0xfc/0x4e0 ksys_write+0x90/0x160 system_call_exception+0x178/0x320 system_call_common+0x160/0x2c4 The blocks of the firmware image are copied directly from user memory to objects allocated from flash_block_cache, so flash_block_cache must be created using kmem_cache_create_usercopy() to mark it safe for user access. [mpe: Trim and indent oops]
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Meta Information
Published
2025-10-01
Last Modified
2025-10-02
Generated
2026-06-16
AI Q&A
2025-10-01
EPSS Evaluated
2026-06-15
NVD
CVE-2023-53487
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.5.0-rc3
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability occurs in the Linux kernel's powerpc/rtas_flash component when hardened usercopy is enabled. It involves the /proc/powerpc/rtas/firmware_update interface used for system firmware updates. The issue arises because blocks of the firmware image are copied directly from user memory to objects allocated from flash_block_cache without proper safety markings. This leads to a kernel BUG and an exception in kernel mode, potentially causing system instability or crashes. The root cause is that flash_block_cache was not created using kmem_cache_create_usercopy(), which is necessary to mark it safe for user access.

Impact Analysis

This vulnerability can cause a kernel BUG and an exception in kernel mode, leading to system crashes or instability during firmware updates via the /proc/powerpc/rtas/firmware_update interface. This could disrupt normal system operations, potentially causing downtime or requiring system reboots.

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