CVE-2026-43380hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

Official description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/a0fc1b9c738fba231f190ab960c83202722efee5
• https://git.kernel.org/stable/c/c59090c50f62a17129fc4c5407bc4071305a9e82
• https://git.kernel.org/stable/c/52db5ef163c96f916d424e472fb17aadc35a9f7a
• https://git.kernel.org/stable/c/b48a0f8d4541a4f6651dc9a64430ce9fdf5c120b
• https://git.kernel.org/stable/c/73a7a345816946d276ad2c46c8bb771de67cfc46
• https://git.kernel.org/stable/c/24a7b9daa103fa963b3fd37d8805b23e01621976
• https://git.kernel.org/stable/c/25dd70a03b1f5f3aa71e1a5091ecd9cd2a13ee43