Commit 32d495b3 authored Apr 10, 2025 by Purva Yeshi Committed by Jarkko Sakkinen May 15, 2025

char: tpm: tpm-buf: Add sanity check fallback in read helpers



Fix Smatch-detected issue:

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'.

Zero-initialize the return values in tpm_buf_read_u8(), tpm_buf_read_u16(),
and tpm_buf_read_u32() to guard against uninitialized data in case of a
boundary overflow.

Add defensive initialization ensures the return values are always defined,
preventing undefined behavior if the unexpected happens.

Signed-off-by: Purva Yeshi <purvayeshi550@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

parent 539fbab3

drivers/char/tpm/tpm-buf.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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);