Bug 2320706 (CVE-2022-48994)

Summary: CVE-2022-48994 kernel: ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event
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 2024-10-21 21:04:01 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event

With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed.

seq_copy_in_user() and seq_copy_in_kernel() did not have prototypes
matching snd_seq_dump_func_t. Adjust this and remove the casts. There
are not resulting binary output differences.

This was found as a result of Clang's new -Wcast-function-type-strict
flag, which is more sensitive than the simpler -Wcast-function-type,
which only checks for type width mismatches.
Comment 1 Avinash Hanwate 2024-10-22 07:25:09 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024102149-CVE-2022-48994-530f@gregkh/T