From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C69B51AF0BB; Fri, 21 Aug 2026 01:07:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787274470; cv=none; b=SPtGDHfMrBkvEMaYlclvSf/CfLftXYvKEwWL6bTMhE4Bh2wJyi8q7QPcFjx10xcLzKa86zbQHrBsNBnc9cuBr8LD9lvWtr5oot0JvH39mWmTQXKqrLeOIjKV4zGr2asPOqPbqzayEvS1YIoBAWILnyIlN19Japi1+sG91vrHe8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787274470; c=relaxed/simple; bh=Qe/hLCLYVsNekNUW0rTbmhzhv2y6kmoRK6z3G/vnB+8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VuW87M+V6lNRTZVp9yWSlAU/OyvnMUTDTp/E/R79Tz5FLjSrwWP5T5TMGrEWIJU0JQuTJDTpugXmjZIfVPa+5CJaFPdrHeTPb7mrmj3qt/sIWkzFlXlhlU9QdgmlSdfdr0CsFnCfHAVx6LbUZv44ibDI/gOKRoXaRjSxG9cmNW4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SaZGx4Et; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SaZGx4Et" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id D05D61F000E9; Fri, 21 Aug 2026 01:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787274469; bh=5ixlCRupb3RSD4KscFNJPtgLQAVPkqF4+DHdRz/PTYw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SaZGx4EtkcsZjVuMIFbZiVSPKvMCPdR4un73a5Zj2uR5GD3bG/gp4C7FjxUSGt1u3 Hm419rV4V8lIrmsa3sxpT5olQPDBLDOvFv9Dn3cWW5GRITjYdlVOcn25+3v3BrWTLA XU6tY3rNzSrHftimVZjyhd2gLPY9/QQ5bTBkbXk1ahWd9KvPc19s++/1T1WhfKHOH4 tcV8uEdWsdub3Loynlsusg7AnQT7Xn7sLMUXBiknQHLqPD1L2/vibYM2yIR+gQBEdx KfeWZ36UkqPPAbyHZwv7eoSncJG9z0W/V4YmpH5HxXtjAVh8iNLT97bBMlNOP8MoXY SRvuG0mrPnXWw== Date: Fri, 21 Aug 2026 04:07:45 +0300 From: Jarkko Sakkinen To: Ruoyu Wang Cc: linux-integrity@vger.kernel.org, peterhuewe@gmx.de, jgg@ziepe.ca, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] tpm: st33zp24: Return zero on status read failure Message-ID: References: <20260813153032.3951878-1-ruoyuw560@gmail.com> Precedence: bulk X-Mailing-List: linux-integrity@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: <20260813153032.3951878-1-ruoyuw560@gmail.com> On Thu, Aug 13, 2026 at 11:30:31PM +0800, Ruoyu Wang wrote: > st33zp24_status() ignores the result of the transport read and returns > data even when no byte was received. The I2C transport, for example, > skips i2c_master_recv() when the register-select write is short or fails, > leaving data uninitialized. The resulting stack value can be interpreted > as TPM_STS flags and let status checks complete spuriously. > > The status callback cannot propagate a transport error. Return zero > unless recv() reports exactly one byte. With no status bits set, callers > retry or take their existing timeout or error path instead of acting on > an invalid status value. > > This issue was found by a static analysis checker and confirmed by manual > source review. > > Fixes: 251a7b08213a ("TPM: STMicroelectronics ST33 I2C KERNEL 3.x") > Signed-off-by: Ruoyu Wang > --- > drivers/char/tpm/st33zp24/st33zp24.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/st33zp24/st33zp24.c b/drivers/char/tpm/st33zp24/st33zp24.c > index e2b7451ea7ccd3..898e8d01d26698 100644 > --- a/drivers/char/tpm/st33zp24/st33zp24.c > +++ b/drivers/char/tpm/st33zp24/st33zp24.c > @@ -93,7 +93,9 @@ static u8 st33zp24_status(struct tpm_chip *chip) > struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); > u8 data; > > - tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1); > + if (tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1) != 1) > + return 0; > + > return data; > } > > -- > 2.51.0 > Reviewed-by: Jarkko Sakkinen thanks BR, Jarkko