CVE-2022-50844

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: Fix type of second parameter in odn_edit_dpm_table() callback

With clangs 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. A proposed warning in clang aims to catch these at compile time, which reveals:

drivers/gpu/drm/amd/amdgpu/../pm/swsmu/amdgpu_smu.c:3008:29: error: incompatible function pointer types initializing int (*)(void *, uint32_t, long , uint32_t) (aka int ()(void *, unsigned int, long *, unsigned int)) with an expression of type int (void *, enum PP_OD_DPM_TABLE_COMMAND, long *, uint32_t) (aka int (void *, enum PP_OD_DPM_TABLE_COMMAND, long *, unsigned int)) [-Werror,-Wincompatible-function-pointer-types-strict] .odn_edit_dpm_table = smu_od_edit_dpm_table, ^~~~~~~~~~~~~~~~~~~~~ 1 error generated.

There are only two implementations of ->odn_edit_dpm_table() in struct amd_pm_funcs: smu_od_edit_dpm_table() and pp_odn_edit_dpm_table(). One has a second parameter type of enum PP_OD_DPM_TABLE_COMMAND and the other uses u32. Ultimately, smu_od_edit_dpm_table() calls ->od_edit_dpm_table() from struct pptable_funcs and pp_odn_edit_dpm_table() calls ->odn_edit_dpm_table() from struct pp_hwmgr_func, which both have a second parameter type of enum PP_OD_DPM_TABLE_COMMAND.

Update the type parameter in both the prototype in struct amd_pm_funcs and pp_odn_edit_dpm_table() to enum PP_OD_DPM_TABLE_COMMAND, which cleans up the warning.

Affected Software

References

• https://git.kernel.org/stable/c/24cba9d865157c9e23128fbcf8b86f5da9570edd
• https://git.kernel.org/stable/c/36217f676b55932a12d6732c95388150015fdee6
• https://git.kernel.org/stable/c/e4d0ef752081e7aa6ffb7ccac11c499c732a2e05
• https://git.kernel.org/stable/c/f9084e9930db562bdcd47fa199a66fb45e16dab5