From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 906DE202C21; Thu, 10 Apr 2025 06:15:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744265703; cv=none; b=AnkEvIF2I9RVezCG+HFzwVYSbnHvjnmm8mSHh/8o8IZUta0ptnPCTdooD/7HNDco4WOYcw5wdm6HS2TqIVmRNyTa4M8eY5tC3mG0YJF8bglZOvSpYuWj37tAZKIRKGn6p2PsB3BLKwETZq17gm0B4o9T2SBBaqY6NMQJVilHVvM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744265703; c=relaxed/simple; bh=zVqocgr36YZsJUJK4G4a6s/8nYUj5HCGaQSX42jvOFU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sphh2AvgYz/obqVRiCJqhEs5GOl8PR6tjO8QBCoB9KbefCPbyb6U4P5Cw+6Dnl2v3Xk9N/5KrjVdTkDIDf7nnwCFBh93g8fn62AGBnTqP30yvGzdXjsjLAylBdBNHHXiumJ20ieTVoEaa49wtAQd99EzAlPsacB0GXieO93U2l4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NylHXf6l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NylHXf6l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75497C4CEDD; Thu, 10 Apr 2025 06:15:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744265703; bh=zVqocgr36YZsJUJK4G4a6s/8nYUj5HCGaQSX42jvOFU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NylHXf6lqaAGXazFBMv88lr1z9ex6hdd51f1u6e7g72x9dM7wcYU7ONP5o0O5jRxV gczLYMI8LDcrdT/x0f+YjYkaLVQsk+SH3mQa05wPfPC8zhaLgCmyBhZo1ofAvriN+v zqQk+zSK9VuGaEBlchIPjbqDwH6SuXj78pa6DhRjuSMHvNe57TGgYj8GhchUWbjbUs f71h1gS1uCGH6M3UXyDyObUabf8y6k5hMDN4h+jAnZJcBi2ElCuL61pfxVcNqf840/ WoaP5t4J5no1nN5uyrT2qlJ9hdAX8R7ociBsBXjbfR9oWz8+TRxxlgqkGuJby5qZ6r /02h0jLwoFmkw== Date: Thu, 10 Apr 2025 09:14:58 +0300 From: Jarkko Sakkinen To: Purva Yeshi Cc: peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] char: tpm: tpm-buf: Fix uninitialized return values in read helpers Message-ID: References: <20250409205536.210202-1-purvayeshi550@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250409205536.210202-1-purvayeshi550@gmail.com> 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 > --- > 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