Bug 2348595 (CVE-2025-21738)

Summary: CVE-2025-21738 kernel: ata: libata-sff: Ensure that we cannot write outside the allocated buffer
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-27 03:04:31 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ata: libata-sff: Ensure that we cannot write outside the allocated buffer

reveliofuzzing reported that a SCSI_IOCTL_SEND_COMMAND ioctl with out_len
set to 0xd42, SCSI command set to ATA_16 PASS-THROUGH, ATA command set to
ATA_NOP, and protocol set to ATA_PROT_PIO, can cause ata_pio_sector() to
write outside the allocated buffer, overwriting random memory.

While a ATA device is supposed to abort a ATA_NOP command, there does seem
to be a bug either in libata-sff or QEMU, where either this status is not
set, or the status is cleared before read by ata_sff_hsm_move().
Anyway, that is most likely a separate bug.

Looking at __atapi_pio_bytes(), it already has a safety check to ensure
that __atapi_pio_bytes() cannot write outside the allocated buffer.

Add a similar check to ata_pio_sector(), such that also ata_pio_sector()
cannot write outside the allocated buffer.
Comment 1 Michal Findra 2025-02-27 19:00:17 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022659-CVE-2025-21738-f502@gregkh/T