Re: [PATCH v2] s390/pci: Fix leak of uninitialized kernel data in SCLP report

> While report_error_write() checks that the provided buffer is at least
> as large as the header struct, but not that it is large enough to
> contain the report with the length claimed by report->length. If
> user-space provides a short buffer, meaning a larger report->length than
> the actually written payload, up to around 4K of kernel data from past
> the kmalloc(len + 1) sized buffer allocated in kernfs_fop_write_iter()
> will leak into the SCLP report.
> 
> However, as the entity processing the SCLP is privileged and able to
> access at least the page including the report, this does not leak data
> that entity could not access but it is still an out of bounds read and
> a malformed error report that should be rejected.
> 
> Fixes: 368704a65be8 ("s390/pci: add report_error attribute")
> Cc: [email protected]
> Signed-off-by: Niklas Schnelle <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260806-fix_pci_sclp_length_check-v2-1-9ee9428e659f@linux.ibm.com?part=1