Bug 2365243 (CVE-2025-37850)

Summary: CVE-2025-37850 kernel: pwm: mediatek: Prevent divide-by-zero in pwm_mediatek_config()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-09 07:01:20 UTC 
In the Linux kernel, the following vulnerability has been resolved:

pwm: mediatek: Prevent divide-by-zero in pwm_mediatek_config()

With CONFIG_COMPILE_TEST && !CONFIG_HAVE_CLK, pwm_mediatek_config() has a
divide-by-zero in the following line:

	do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));

due to the fact that the !CONFIG_HAVE_CLK version of clk_get_rate()
returns zero.

This is presumably just a theoretical problem: COMPILE_TEST overrides
the dependency on RALINK which would select COMMON_CLK.  Regardless it's
a good idea to check for the error explicitly to avoid divide-by-zero.

Fixes the following warning:

  drivers/pwm/pwm-mediatek.o: warning: objtool: .text: unexpected end of section

[ukleinek: s/CONFIG_CLK/CONFIG_HAVE_CLK/]
Comment 1 Michal Findra 2025-05-09 09:43:42 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050919-CVE-2025-37850-80a5@gregkh/T