Re: CVE-2023-52665: powerpc/ps3_defconfig: Disable PPC64_BIG_ENDIAN_ELF_ABI_V2

[Geoff Levand]

On 5/20/24 16:04, Michael Ellerman wrote:
> Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes:
>> Description
>> ===========
>>
>> In the Linux kernel, the following vulnerability has been resolved:
>>
>> powerpc/ps3_defconfig: Disable PPC64_BIG_ENDIAN_ELF_ABI_V2
>>
>> Commit 8c5fa3b5c4df ("powerpc/64: Make ELFv2 the default for big-endian
>> builds"), merged in Linux-6.5-rc1 changes the calling ABI in a way
>> that is incompatible with the current code for the PS3's LV1 hypervisor
>> calls.
>>
>> This change just adds the line '# CONFIG_PPC64_BIG_ENDIAN_ELF_ABI_V2 is not set'
>> to the ps3_defconfig file so that the PPC64_ELF_ABI_V1 is used.
>>
>> Fixes run time errors like these:
>>
>>   BUG: Kernel NULL pointer dereference at 0x00000000
>>   Faulting instruction address: 0xc000000000047cf0
>>   Oops: Kernel access of bad area, sig: 11 [#1]
>>   Call Trace:
>>   [c0000000023039e0] [c00000000100ebfc] ps3_create_spu+0xc4/0x2b0 (unreliable)
>>   [c000000002303ab0] [c00000000100d4c4] create_spu+0xcc/0x3c4
>>   [c000000002303b40] [c00000000100eae4] ps3_enumerate_spus+0xa4/0xf8
>>
>> The Linux kernel CVE team has assigned CVE-2023-52665 to this issue.
> 
> IMHO this doesn't warrant a CVE. The crash mentioned above happens at
> boot, so the system is not vulnerable it's just broken :)

As Greg says, with PPC64_BIG_ENDIAN_ELF_ABI_V2 enabled the system won't
boot, so there is no chance of a vulnerability.

-Geoff