linux-kernel - Re: [PATCH] scsi: qlogicpti: Mark expected switch fall-throughs

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: <201907290859.FCDA1B9F@keescook>
Date:   Mon, 29 Jul 2019 08:59:36 -0700
From:   Kees Cook <keescook@...omium.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Stephen Rothwell <sfr@...b.auug.org.au>
Subject: Re: [PATCH] scsi: qlogicpti: Mark expected switch fall-throughs

On Mon, Jul 29, 2019 at 06:03:45AM -0500, Gustavo A. R. Silva wrote:
> Mark switch cases where we are expecting to fall through.
> 
> This patch fixes the following warnings (Building: sparc defconfig):
> 
> drivers/scsi/qlogicpti.c: In function 'qlogicpti_mbox_command':
> drivers/scsi/qlogicpti.c:202:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 6: sbus_writew(param[5], qpti->qregs + MBOX5);
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:203:2: note: here
>   case 5: sbus_writew(param[4], qpti->qregs + MBOX4);
>   ^~~~
> drivers/scsi/qlogicpti.c:203:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 5: sbus_writew(param[4], qpti->qregs + MBOX4);
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:204:2: note: here
>   case 4: sbus_writew(param[3], qpti->qregs + MBOX3);
>   ^~~~
> drivers/scsi/qlogicpti.c:204:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 4: sbus_writew(param[3], qpti->qregs + MBOX3);
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:205:2: note: here
>   case 3: sbus_writew(param[2], qpti->qregs + MBOX2);
>   ^~~~
> drivers/scsi/qlogicpti.c:205:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 3: sbus_writew(param[2], qpti->qregs + MBOX2);
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:206:2: note: here
>   case 2: sbus_writew(param[1], qpti->qregs + MBOX1);
>   ^~~~
> drivers/scsi/qlogicpti.c:206:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 2: sbus_writew(param[1], qpti->qregs + MBOX1);
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:207:2: note: here
>   case 1: sbus_writew(param[0], qpti->qregs + MBOX0);
>   ^~~~
> drivers/scsi/qlogicpti.c:256:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 6: param[5] = sbus_readw(qpti->qregs + MBOX5);
>           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:257:2: note: here
>   case 5: param[4] = sbus_readw(qpti->qregs + MBOX4);
>   ^~~~
> drivers/scsi/qlogicpti.c:257:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 5: param[4] = sbus_readw(qpti->qregs + MBOX4);
>           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:258:2: note: here
>   case 4: param[3] = sbus_readw(qpti->qregs + MBOX3);
>   ^~~~
> drivers/scsi/qlogicpti.c:258:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 4: param[3] = sbus_readw(qpti->qregs + MBOX3);
>           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:259:2: note: here
>   case 3: param[2] = sbus_readw(qpti->qregs + MBOX2);
>   ^~~~
> drivers/scsi/qlogicpti.c:259:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 3: param[2] = sbus_readw(qpti->qregs + MBOX2);
>           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:260:2: note: here
>   case 2: param[1] = sbus_readw(qpti->qregs + MBOX1);
>   ^~~~
> drivers/scsi/qlogicpti.c:260:19: warning: this statement may fall through [-Wimplicit-fallthrough=]
>   case 2: param[1] = sbus_readw(qpti->qregs + MBOX1);
>           ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/qlogicpti.c:261:2: note: here
>   case 1: param[0] = sbus_readw(qpti->qregs + MBOX0);
>   ^~~~
> 
> Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Reviewed-by: Kees Cook <keescook@...omium.org>

-Kees

> ---
>  drivers/scsi/qlogicpti.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/scsi/qlogicpti.c b/drivers/scsi/qlogicpti.c
> index 9335849f6bea..d539beef3ce8 100644
> --- a/drivers/scsi/qlogicpti.c
> +++ b/drivers/scsi/qlogicpti.c
> @@ -200,10 +200,15 @@ static int qlogicpti_mbox_command(struct qlogicpti *qpti, u_short param[], int f
>  	/* Write mailbox command registers. */
>  	switch (mbox_param[param[0]] >> 4) {
>  	case 6: sbus_writew(param[5], qpti->qregs + MBOX5);
> +		/* Fall through */
>  	case 5: sbus_writew(param[4], qpti->qregs + MBOX4);
> +		/* Fall through */
>  	case 4: sbus_writew(param[3], qpti->qregs + MBOX3);
> +		/* Fall through */
>  	case 3: sbus_writew(param[2], qpti->qregs + MBOX2);
> +		/* Fall through */
>  	case 2: sbus_writew(param[1], qpti->qregs + MBOX1);
> +		/* Fall through */
>  	case 1: sbus_writew(param[0], qpti->qregs + MBOX0);
>  	}
>  
> @@ -254,10 +259,15 @@ static int qlogicpti_mbox_command(struct qlogicpti *qpti, u_short param[], int f
>  	/* Read back output parameters. */
>  	switch (mbox_param[param[0]] & 0xf) {
>  	case 6: param[5] = sbus_readw(qpti->qregs + MBOX5);
> +		/* Fall through */
>  	case 5: param[4] = sbus_readw(qpti->qregs + MBOX4);
> +		/* Fall through */
>  	case 4: param[3] = sbus_readw(qpti->qregs + MBOX3);
> +		/* Fall through */
>  	case 3: param[2] = sbus_readw(qpti->qregs + MBOX2);
> +		/* Fall through */
>  	case 2: param[1] = sbus_readw(qpti->qregs + MBOX1);
> +		/* Fall through */
>  	case 1: param[0] = sbus_readw(qpti->qregs + MBOX0);
>  	}
>  
> -- 
> 2.22.0
> 

-- 
Kees Cook