Re: [PATCH] hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

[Andy Shevchenko]

On Wed, Mar 04, 2026 at 01:00:55AM +0000, Sanman Pradhan wrote:
> From 166d8a9220dc783b752cb212937a31e6e1adc811 Mon Sep 17 00:00:00 2001
> From: Sanman Pradhan <psanman@xxxxxxxxxxx>
> Date: Tue, 3 Mar 2026 16:22:08 -0800
> Subject: [PATCH] hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

Something went wrong with your email.

Code wise the change LGTM.

> The q54sj108a2_debugfs_read function suffers from a stack buffer overflow
> due to incorrect arguments passed to bin2hex(). The function currently
> passes 'data' as the destination and 'data_char' as the source.
> 
> Because bin2hex() converts each input byte into two hex characters, a
> 32-byte block read results in 64 bytes of output. Since 'data' is only
> 34 bytes (I2C_SMBUS_BLOCK_MAX + 2), this writes 30 bytes past the end
> of the buffer onto the stack.
> 
> Additionally, the arguments were swapped: it was reading from the
> zero-initialized 'data_char' and writing to 'data', resulting in
> all-zero output regardless of the actual I2C read.
> 
> Fix this by:
> 1. Expanding 'data_char' to 66 bytes to safely hold the hex output.
> 2. Correcting the bin2hex() argument order and using the actual read count.
> 3. Using a pointer to select the correct output buffer for the final
>    simple_read_from_buffer call.

...

> -- 
> 2.34.1
> 
> 
> Thank you.
> 
> Regards,
> Sanman Pradhan

Ah, you copied and pasted the real email into another one. No, please use
proper tooling, exempli gratia `git send-email`.

-- 
With Best Regards,
Andy Shevchenko