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synced 2026-09-22 09:34:56 +02:00
Sanman Pradhan
357ef14bfd
commitd6cc7c99bfupstream. ltc2992_set_voltage(), ltc2992_set_current(), and ltc2992_set_power() do not validate the user-supplied value before converting it to a register value. This can result in: 1. Negative input values wrapping to large positive register values. For power, the negative long is implicitly cast to u64 in mul_u64_u32_div(), producing an incorrect value. For voltage and current, the negative converted value wraps when passed to ltc2992_write_reg() as a u32. 2. Intermediate arithmetic exceeding the range representable in u64 on 64-bit platforms. In ltc2992_set_voltage(), (u64)val * 1000 can exceed U64_MAX when val is a large positive long. In ltc2992_set_current(), (u64)val * r_sense_uohm can overflow similarly. In ltc2992_set_power(), the computed value may not fit in u64. 3. Register values exceeding the hardware field width. Voltage and current threshold registers are 12-bit (stored left-justified in 16 bits), and power threshold registers are 24-bit. Without clamping, bits above the field width are truncated in ltc2992_write_reg(). Fix by clamping negative values to zero, clamping positive values to the rounded hardware-representable maximum (the value returned by the read path for a full-scale register) to prevent intermediate overflow, and clamping the converted register value to the hardware field width before writing. The existing conversion formula and rounding behavior are preserved. In the power write path, cancel the factor of 1000 from both the numerator (r_sense_uohm * 1000) and the denominator (VADC_UV_LSB * IADC_NANOV_LSB) to also eliminate a u32 overflow of r_sense_uohm * 1000 when r_sense_uohm exceeds about 4.29 ohms. Fixes:b0bd407e94("hwmon: (ltc2992) Add support") Cc: stable@vger.kernel.org Signed-off-by: Sanman Pradhan <psanman@juniper.net> Link: https://lore.kernel.org/r/20260416215904.101969-2-sanman.pradhan@hpe.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.