Bug 2400690 (CVE-2023-53458)

Summary: CVE-2023-53458 kernel: media: cx23885: Fix a null-ptr-deref bug in buffer_prepare() and buffer_finish()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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OS: Linux   
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Description OSIDB Bzimport 2025-10-01 12:01:49 UTC 
In the Linux kernel, the following vulnerability has been resolved:

media: cx23885: Fix a null-ptr-deref bug in buffer_prepare() and buffer_finish()

When the driver calls cx23885_risc_buffer() to prepare the buffer, the
function call dma_alloc_coherent may fail, resulting in a empty buffer
risc->cpu. Later when we free the buffer or access the buffer, null ptr
deref is triggered.

This bug is similar to the following one:
https://git.linuxtv.org/media_stage.git/commit/?id=2b064d91440b33fba5b452f2d1b31f13ae911d71.

We believe the bug can be also dynamically triggered from user side.
Similarly, we fix this by checking the return value of cx23885_risc_buffer()
and the value of risc->cpu before buffer free.
Comment 1 Jon Moroney 2025-10-01 23:54:23 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100105-CVE-2023-53458-8239@gregkh/T