[PATCH 6.12 49/55] char: tpm: tpm-buf: Add sanity check fallback in read helpers

6.12-stable review patch. If anyone has any objections, please let me know.

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From: Purva Yeshi purvayeshi550@gmail.com

[ Upstream commit 32d495b384a2db7d23c2295e03e6b6edb1c0db8d ]

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 Signed-off-by: Sasha Levin sashal@kernel.org --- 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 e49a19fea3bdf..dc882fc9fa9ef 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);