linux-kernel - Re: [PATCH v2] char: tpm: tpm-buf: Add sanity check fallback in read helpers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6w3lsskngim3x6lx7akwfly3hrrzxyi4pq4itwyye3rywlqum7@oiwkjmvtawl7>
Date: Fri, 11 Apr 2025 09:20:57 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: Purva Yeshi <purvayeshi550@...il.com>
Cc: peterhuewe@....de, jarkko@...nel.org, jgg@...pe.ca, 
	linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] char: tpm: tpm-buf: Add sanity check fallback in read
 helpers

On Thu, Apr 10, 2025 at 04:04:42PM +0530, Purva Yeshi wrote:
>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@...il.com>
>---
>V1 - https://lore.kernel.org/all/20250409205536.210202-1-purvayeshi550@gmail.com/
>V2 - Update commit message to clarify patch adds a sanity check

LGTM!

Reviewed-by: Stefano Garzarella <sgarzare@...hat.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
>
>