On Thu, Apr 10, 2025 at 02:25:36AM +0530, Purva Yeshi wrote:
> Fix Smatch-detected error:
> drivers/char/tpm/tpm-buf.c:208 tpm_buf_read_u8() error:
> uninitialized symbol 'value'.
> drivers/char/tpm/tpm-buf.c:225 tpm_buf_read_u16() error:
> uninitialized symbol 'value'.
> drivers/char/tpm/tpm-buf.c:242 tpm_buf_read_u32() error:
> uninitialized symbol 'value'.
>
> Call tpm_buf_read() to populate value but do not check its return
> status. If the read fails, value remains uninitialized, causing
> undefined behavior when returned or processed.
>
> Initialize value to zero to ensure a defined return even if
> tpm_buf_read() fails, avoiding undefined behavior from using
> an uninitialized variable.
How does tpm_buf_read() fail?
>
> Signed-off-by: Purva Yeshi <purvayeshi...@gmail.com>
> ---
> drivers/char/tpm/tpm-buf.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
> index e49a19fea3bd..dc882fc9fa9e 100644
> --- a/drivers/char/tpm/tpm-buf.c
> +++ b/drivers/char/tpm/tpm-buf.c
> @@ -201,7 +201,7 @@ static void tpm_buf_read(struct tpm_buf *buf, off_t
> *offset, size_t count, void
> */
> u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset)
> {
> - u8 value;
> + u8 value = 0;
>
> tpm_buf_read(buf, offset, sizeof(value), &value);
>
> @@ -218,7 +218,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_read_u8);
> */
> u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset)
> {
> - u16 value;
> + u16 value = 0;
>
> tpm_buf_read(buf, offset, sizeof(value), &value);
>
> @@ -235,7 +235,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_read_u16);
> */
> u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset)
> {
> - u32 value;
> + u32 value = 0;
>
> tpm_buf_read(buf, offset, sizeof(value), &value);
>
> --
> 2.34.1
>
BR, Jarkko
