CVE-2023-53487

powerpc/rtas_flash: allow user copy to flash block cache objects

State: Published
Severity: Not scored
Published: Oct 1, 2025
Updated: May 11, 2026
Reserved: Oct 1, 2025

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]

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	6d07d1cd300f4c7e16005f881fea388164999cc8 to before 8f09cc15dcd91d16562400c51d24c7be0d5796faAffected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before 1d29e21ed09fa668416fa7721e08d451b9903485Affected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before 0ba7f969be599e21d4b1f1e947593de6515f4996Affected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before 8ef25fb13494e35c6dbe15445c7875fa92bc3e8bAffected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before b8fee83aa4ed3846c7f50a0b364bc699f48d96e5Affected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before 6acb8a453388374fafb3c3b37534b675b2aa0ae1Affected 6d07d1cd300f4c7e16005f881fea388164999cc8 to before 4f3175979e62de3b929bfa54a0db4b87d36257a7Affected
LinuxLinux	4.16Affected before 4.16Not affected 4.19.293 through 4.19.Not affected 5.4.255 through 5.4.Not affected 5.10.192 through 5.10.Not affected 5.15.128 through 5.15.Not affected 6.1.47 through 6.1.Not affected 6.4.12 through 6.4.Not affected 6.5 and laterNot affected

Product

Versions

LinuxLinux

6d07d1cd300f4c7e16005f881fea388164999cc8 to before 8f09cc15dcd91d16562400c51d24c7be0d5796faAffected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before 1d29e21ed09fa668416fa7721e08d451b9903485Affected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before 0ba7f969be599e21d4b1f1e947593de6515f4996Affected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before 8ef25fb13494e35c6dbe15445c7875fa92bc3e8bAffected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before b8fee83aa4ed3846c7f50a0b364bc699f48d96e5Affected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before 6acb8a453388374fafb3c3b37534b675b2aa0ae1Affected
6d07d1cd300f4c7e16005f881fea388164999cc8 to before 4f3175979e62de3b929bfa54a0db4b87d36257a7Affected

LinuxLinux

4.16Affected
before 4.16Not affected
4.19.293 through 4.19.*Not affected
5.4.255 through 5.4.*Not affected
5.10.192 through 5.10.*Not affected
5.15.128 through 5.15.*Not affected
6.1.47 through 6.1.*Not affected
6.4.12 through 6.4.*Not affected
6.5 and laterNot affected

References

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