In the Linux kernel, the following vulnerability has been resolved:
hwmon: (macsmc) Fix regressions in Apple Silicon SMC hwmon driver
The recently added macsmc-hwmon driver contained several critical
bugs in its sensor population logic and float conversion routines.
Specifically:
- The voltage sensor population loop used the wrong prefix ("volt-"
instead of "voltage-") and incorrectly assigned sensors to the
temperature sensor array (hwmon->temp.sensors) instead of the
voltage sensor array (hwmon->volt.sensors). This would lead to
out-of-bounds memory access or data corruption when both temperature
and voltage sensors were present.
- The float conversion in macsmc_hwmon_write_f32() had flawed exponent
logic for values >= 2^24 and lacked masking for the mantissa, which
could lead to incorrect values being written to the SMC.
Fix these issues to ensure correct sensor registration and reliable
manual fan control.
Confirm that the reported overflow in FIELD_PREP is fixed by declaring
macsmc_hwmon_write_f32() as __always_inline for a compile test.