On Wed, Sep 17, 2025 at 03:29:56PM +0000, Gunnar Kudrjavets wrote:
> When len is 0, the while loop in tpm_tis_spi_transfer_half() never
> executes, leaving ret uninitialized. This will lead to undefined
> behavior when the function returns.
>
> The issue was introduced when tpm_tis_spi_transfer() was refactored
> to call tpm_tis_spi_transfer_half() or tpm_tis_spi_transfer_full().
> While ret is properly initialized in tpm_tis_spi_transfer_full(), it
> was missed in tpm_tis_spi_transfer_half().
>
> Initialize ret to 0 at the beginning of the function to ensure
> defined behavior in all code paths.
>
> Found by GCC 14.2.0 static analyzer with -fanalyzer.
>
> Fixes: a86a42ac2bd6 ("tpm_tis_spi: Add hardware wait polling")
> Signed-off-by: Gunnar Kudrjavets <[email protected]>
> Reviewed-by: Justinien Bouron <[email protected]>
> ---
> drivers/char/tpm/tpm_tis_spi_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_spi_main.c
> b/drivers/char/tpm/tpm_tis_spi_main.c
> index 61b42c83ced8..1b6d79662ca1 100644
> --- a/drivers/char/tpm/tpm_tis_spi_main.c
> +++ b/drivers/char/tpm/tpm_tis_spi_main.c
> @@ -85,7 +85,7 @@ static int tpm_tis_spi_transfer_half(struct tpm_tis_data
> *data, u32 addr,
> struct spi_transfer spi_xfer[3];
> struct spi_message m;
> u8 transfer_len;
> - int ret;
> + int ret = 0;
>
> while (len) {
> transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
>
> base-commit: 5aca7966d2a7255ba92fd5e63268dd767b223aa5
> --
> 2.47.3
>
Thank you.
I just applied the earlier fix, and I'll apply this too (before next
PR).
Reviewed-by: Jarkko Sakkinen <[email protected]>
BR, Jarkko
