[PATCH][next] scsi: Replace one-element arrays with flexible-array members

[PATCH][next] scsi: Replace one-element arrays with flexible-array members

[Gustavo A. R. Silva]

Use flexible-array members in struct fc_fdmi_attr_entry and
fs_fdmi_attrs instead of one-element arrays, and refactor the
code accordingly.

Also, turn the one-element array _port_ in struct fc_fdmi_rpl
into a simple object of type struct fc_fdmi_port_name, as it
seems there is no more than just one port expected:

$ git grep -nw numport drivers/scsi/
drivers/scsi/csiostor/csio_lnode.c:447: reg_pl->numport = htonl(1);
drivers/scsi/libfc/fc_encode.h:232:             put_unaligned_be32(1, &ct->payload.rhba.port.numport);

Also, this helps with the ongoing efforts to globally enable
-Warray-bounds and get us closer to being able to tighten the
FORTIFY_SOURCE routines on memcpy().

https://github.com/KSPP/linux/issues/79
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/scsi/csiostor/csio_lnode.c | 2 +-
 drivers/scsi/libfc/fc_encode.h     | 4 ++--
 include/scsi/fc/fc_ms.h            | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
index d5ac93897023..cf9dd79ee488 100644
--- a/drivers/scsi/csiostor/csio_lnode.c
+++ b/drivers/scsi/csiostor/csio_lnode.c
@@ -445,7 +445,7 @@ csio_ln_fdmi_dprt_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
 	/* Register one port per hba */
 	reg_pl = (struct fc_fdmi_rpl *)pld;
 	reg_pl->numport = htonl(1);
-	memcpy(&reg_pl->port[0].portname, csio_ln_wwpn(ln), 8);
+	memcpy(&reg_pl->port.portname, csio_ln_wwpn(ln), 8);
 	pld += sizeof(*reg_pl);
 
 	/* Start appending HBA attributes hba */
diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
index 74ae7fd15d8d..5806f99e4061 100644
--- a/drivers/scsi/libfc/fc_encode.h
+++ b/drivers/scsi/libfc/fc_encode.h
@@ -232,7 +232,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
 		put_unaligned_be32(1, &ct->payload.rhba.port.numport);
 		/* Port Name */
 		put_unaligned_be64(lport->wwpn,
-				   &ct->payload.rhba.port.port[0].portname);
+				   &ct->payload.rhba.port.port.portname);
 
 		/* HBA Attributes */
 		put_unaligned_be32(numattrs,
@@ -246,7 +246,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
 				   &entry->type);
 		put_unaligned_be16(len, &entry->len);
 		put_unaligned_be64(lport->wwnn,
-				   (__be64 *)&entry->value[0]);
+				   (__be64 *)&entry->value);
 
 		/* Manufacturer */
 		entry = (struct fc_fdmi_attr_entry *)((char *)entry->value +
diff --git a/include/scsi/fc/fc_ms.h b/include/scsi/fc/fc_ms.h
index 00191695233a..44fbe84fa664 100644
--- a/include/scsi/fc/fc_ms.h
+++ b/include/scsi/fc/fc_ms.h
@@ -158,7 +158,7 @@ struct fc_fdmi_port_name {
 struct fc_fdmi_attr_entry {
 	__be16		type;
 	__be16		len;
-	__u8		value[1];
+	__u8		value[];
 } __attribute__((__packed__));
 
 /*
@@ -166,7 +166,7 @@ struct fc_fdmi_attr_entry {
  */
 struct fs_fdmi_attrs {
 	__be32				numattrs;
-	struct fc_fdmi_attr_entry	attr[1];
+	struct fc_fdmi_attr_entry	attr[];
 } __attribute__((__packed__));
 
 /*
@@ -174,7 +174,7 @@ struct fs_fdmi_attrs {
  */
 struct fc_fdmi_rpl {
 	__be32				numport;
-	struct fc_fdmi_port_name	port[1];
+	struct fc_fdmi_port_name	port;
 } __attribute__((__packed__));
 
 /*
-- 
2.27.0

Re: [PATCH][next] scsi: Replace one-element arrays with flexible-array members

[Steffen Maier]

On 11/5/21 10:11, Gustavo A. R. Silva wrote:
> Use flexible-array members in struct fc_fdmi_attr_entry and
> fs_fdmi_attrs instead of one-element arrays, and refactor the
> code accordingly.
> 
> Also, turn the one-element array _port_ in struct fc_fdmi_rpl
> into a simple object of type struct fc_fdmi_port_name, as it
> seems there is no more than just one port expected:
> 
> $ git grep -nw numport drivers/scsi/
> drivers/scsi/csiostor/csio_lnode.c:447: reg_pl->numport = htonl(1);
> drivers/scsi/libfc/fc_encode.h:232:             put_unaligned_be32(1, &ct->payload.rhba.port.numport);
> 
> Also, this helps with the ongoing efforts to globally enable
> -Warray-bounds and get us closer to being able to tighten the
> FORTIFY_SOURCE routines on memcpy().
> 
> https://github.com/KSPP/linux/issues/79
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>   drivers/scsi/csiostor/csio_lnode.c | 2 +-
>   drivers/scsi/libfc/fc_encode.h     | 4 ++--
>   include/scsi/fc/fc_ms.h            | 6 +++---
>   3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
> index d5ac93897023..cf9dd79ee488 100644
> --- a/drivers/scsi/csiostor/csio_lnode.c
> +++ b/drivers/scsi/csiostor/csio_lnode.c
> @@ -445,7 +445,7 @@ csio_ln_fdmi_dprt_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
>   	/* Register one port per hba */
>   	reg_pl = (struct fc_fdmi_rpl *)pld;
>   	reg_pl->numport = htonl(1);
> -	memcpy(&reg_pl->port[0].portname, csio_ln_wwpn(ln), 8);
> +	memcpy(&reg_pl->port.portname, csio_ln_wwpn(ln), 8);
>   	pld += sizeof(*reg_pl);
> 
>   	/* Start appending HBA attributes hba */
> diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
> index 74ae7fd15d8d..5806f99e4061 100644
> --- a/drivers/scsi/libfc/fc_encode.h
> +++ b/drivers/scsi/libfc/fc_encode.h
> @@ -232,7 +232,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
>   		put_unaligned_be32(1, &ct->payload.rhba.port.numport);
>   		/* Port Name */
>   		put_unaligned_be64(lport->wwpn,
> -				   &ct->payload.rhba.port.port[0].portname);
> +				   &ct->payload.rhba.port.port.portname);
> 
>   		/* HBA Attributes */
>   		put_unaligned_be32(numattrs,

> diff --git a/include/scsi/fc/fc_ms.h b/include/scsi/fc/fc_ms.h
> index 00191695233a..44fbe84fa664 100644
> --- a/include/scsi/fc/fc_ms.h
> +++ b/include/scsi/fc/fc_ms.h

> @@ -174,7 +174,7 @@ struct fs_fdmi_attrs {

/*
  * Registered Port List

>    */
>   struct fc_fdmi_rpl {
>   	__be32				numport;
> -	struct fc_fdmi_port_name	port[1];
> +	struct fc_fdmi_port_name	port;
>   } __attribute__((__packed__));

While I'm not affected by the change, it feels to me as if these are protocol 
definitions originating in a T11 Fibre Channel standard FC-GS. It's a port 
*list*. Can you "modify" the standard here?

The fact, that currently existing code users only ever seem to use one single 
port in the list, would be an independent thing to me.


-- 
Mit freundlichen Gruessen / Kind regards
Steffen Maier

Linux on IBM Z and LinuxONE

https://www.ibm.com/privacy/us/en/
IBM Deutschland Research & Development GmbH
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Registergericht: Amtsgericht Stuttgart, HRB 243294

Re: [PATCH][next] scsi: Replace one-element arrays with flexible-array members

[Kees Cook]

On Fri, Nov 05, 2021 at 12:24:13PM +0100, Steffen Maier wrote:
> On 11/5/21 10:11, Gustavo A. R. Silva wrote:
> > Use flexible-array members in struct fc_fdmi_attr_entry and
> > fs_fdmi_attrs instead of one-element arrays, and refactor the
> > code accordingly.
> > 
> > Also, turn the one-element array _port_ in struct fc_fdmi_rpl
> > into a simple object of type struct fc_fdmi_port_name, as it
> > seems there is no more than just one port expected:
> > 
> > $ git grep -nw numport drivers/scsi/
> > drivers/scsi/csiostor/csio_lnode.c:447: reg_pl->numport = htonl(1);
> > drivers/scsi/libfc/fc_encode.h:232:             put_unaligned_be32(1, &ct->payload.rhba.port.numport);
> > 
> > Also, this helps with the ongoing efforts to globally enable
> > -Warray-bounds and get us closer to being able to tighten the
> > FORTIFY_SOURCE routines on memcpy().
> > 
> > https://github.com/KSPP/linux/issues/79
> > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> > ---
> >   drivers/scsi/csiostor/csio_lnode.c | 2 +-
> >   drivers/scsi/libfc/fc_encode.h     | 4 ++--
> >   include/scsi/fc/fc_ms.h            | 6 +++---
> >   3 files changed, 6 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
> > index d5ac93897023..cf9dd79ee488 100644
> > --- a/drivers/scsi/csiostor/csio_lnode.c
> > +++ b/drivers/scsi/csiostor/csio_lnode.c
> > @@ -445,7 +445,7 @@ csio_ln_fdmi_dprt_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
> >   	/* Register one port per hba */
> >   	reg_pl = (struct fc_fdmi_rpl *)pld;
> >   	reg_pl->numport = htonl(1);
> > -	memcpy(&reg_pl->port[0].portname, csio_ln_wwpn(ln), 8);
> > +	memcpy(&reg_pl->port.portname, csio_ln_wwpn(ln), 8);
> >   	pld += sizeof(*reg_pl);
> > 
> >   	/* Start appending HBA attributes hba */
> > diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
> > index 74ae7fd15d8d..5806f99e4061 100644
> > --- a/drivers/scsi/libfc/fc_encode.h
> > +++ b/drivers/scsi/libfc/fc_encode.h
> > @@ -232,7 +232,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
> >   		put_unaligned_be32(1, &ct->payload.rhba.port.numport);
> >   		/* Port Name */
> >   		put_unaligned_be64(lport->wwpn,
> > -				   &ct->payload.rhba.port.port[0].portname);
> > +				   &ct->payload.rhba.port.port.portname);
> > 
> >   		/* HBA Attributes */
> >   		put_unaligned_be32(numattrs,
> 
> > diff --git a/include/scsi/fc/fc_ms.h b/include/scsi/fc/fc_ms.h
> > index 00191695233a..44fbe84fa664 100644
> > --- a/include/scsi/fc/fc_ms.h
> > +++ b/include/scsi/fc/fc_ms.h
> 
> > @@ -174,7 +174,7 @@ struct fs_fdmi_attrs {
> 
> /*
>  * Registered Port List
> 
> >    */
> >   struct fc_fdmi_rpl {
> >   	__be32				numport;
> > -	struct fc_fdmi_port_name	port[1];
> > +	struct fc_fdmi_port_name	port;
> >   } __attribute__((__packed__));
> 
> While I'm not affected by the change, it feels to me as if these are
> protocol definitions originating in a T11 Fibre Channel standard FC-GS. It's
> a port *list*. Can you "modify" the standard here?
> 
> The fact, that currently existing code users only ever seem to use one
> single port in the list, would be an independent thing to me.

There are three changes made here, and I suspect it might make sense to
split them up.

In a quick look, I see "struct fc_fdmi_attr_entry" has a sizeof() call
against it, so it's not clear if it's safe to switch it to a flexible
array without other changes.

The change to struct fs_fdmi_attrs looks okay, since it appears to be
used only in casts, but it might make sense to use diffoscope on the
changed .o files to validate nothing weird has happened.

For struct fc_dmi_rpl, as long as "numport" is always set/validated to
1, I think this change is fine.

-- 
Kees Cook

Re: [PATCH][next] scsi: Replace one-element arrays with flexible-array members

[Gustavo A. R. Silva]

On Thu, Dec 02, 2021 at 11:23:26AM -0800, Kees Cook wrote:
> On Fri, Nov 05, 2021 at 12:24:13PM +0100, Steffen Maier wrote:
> > On 11/5/21 10:11, Gustavo A. R. Silva wrote:
> > > Use flexible-array members in struct fc_fdmi_attr_entry and
> > > fs_fdmi_attrs instead of one-element arrays, and refactor the
> > > code accordingly.
> > > 
> > > Also, turn the one-element array _port_ in struct fc_fdmi_rpl
> > > into a simple object of type struct fc_fdmi_port_name, as it
> > > seems there is no more than just one port expected:
> > > 
> > > $ git grep -nw numport drivers/scsi/
> > > drivers/scsi/csiostor/csio_lnode.c:447: reg_pl->numport = htonl(1);
> > > drivers/scsi/libfc/fc_encode.h:232:             put_unaligned_be32(1, &ct->payload.rhba.port.numport);
> > > 
> > > Also, this helps with the ongoing efforts to globally enable
> > > -Warray-bounds and get us closer to being able to tighten the
> > > FORTIFY_SOURCE routines on memcpy().
> > > 
> > > https://github.com/KSPP/linux/issues/79
> > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> > > ---
> > >   drivers/scsi/csiostor/csio_lnode.c | 2 +-
> > >   drivers/scsi/libfc/fc_encode.h     | 4 ++--
> > >   include/scsi/fc/fc_ms.h            | 6 +++---
> > >   3 files changed, 6 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
> > > index d5ac93897023..cf9dd79ee488 100644
> > > --- a/drivers/scsi/csiostor/csio_lnode.c
> > > +++ b/drivers/scsi/csiostor/csio_lnode.c
> > > @@ -445,7 +445,7 @@ csio_ln_fdmi_dprt_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
> > >   	/* Register one port per hba */
> > >   	reg_pl = (struct fc_fdmi_rpl *)pld;
> > >   	reg_pl->numport = htonl(1);
> > > -	memcpy(&reg_pl->port[0].portname, csio_ln_wwpn(ln), 8);
> > > +	memcpy(&reg_pl->port.portname, csio_ln_wwpn(ln), 8);
> > >   	pld += sizeof(*reg_pl);
> > > 
> > >   	/* Start appending HBA attributes hba */
> > > diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
> > > index 74ae7fd15d8d..5806f99e4061 100644
> > > --- a/drivers/scsi/libfc/fc_encode.h
> > > +++ b/drivers/scsi/libfc/fc_encode.h
> > > @@ -232,7 +232,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
> > >   		put_unaligned_be32(1, &ct->payload.rhba.port.numport);
> > >   		/* Port Name */
> > >   		put_unaligned_be64(lport->wwpn,
> > > -				   &ct->payload.rhba.port.port[0].portname);
> > > +				   &ct->payload.rhba.port.port.portname);
> > > 
> > >   		/* HBA Attributes */
> > >   		put_unaligned_be32(numattrs,
> > 
> > > diff --git a/include/scsi/fc/fc_ms.h b/include/scsi/fc/fc_ms.h
> > > index 00191695233a..44fbe84fa664 100644
> > > --- a/include/scsi/fc/fc_ms.h
> > > +++ b/include/scsi/fc/fc_ms.h
> > 
> > > @@ -174,7 +174,7 @@ struct fs_fdmi_attrs {
> > 
> > /*
> >  * Registered Port List
> > 
> > >    */
> > >   struct fc_fdmi_rpl {
> > >   	__be32				numport;
> > > -	struct fc_fdmi_port_name	port[1];
> > > +	struct fc_fdmi_port_name	port;
> > >   } __attribute__((__packed__));
> > 
> > While I'm not affected by the change, it feels to me as if these are
> > protocol definitions originating in a T11 Fibre Channel standard FC-GS. It's
> > a port *list*. Can you "modify" the standard here?
> > 
> > The fact, that currently existing code users only ever seem to use one
> > single port in the list, would be an independent thing to me.
> 
> There are three changes made here, and I suspect it might make sense to
> split them up.
> 
> In a quick look, I see "struct fc_fdmi_attr_entry" has a sizeof() call
> against it, so it's not clear if it's safe to switch it to a flexible
> array without other changes.

I'll take a look.

> The change to struct fs_fdmi_attrs looks okay, since it appears to be
> used only in casts, but it might make sense to use diffoscope on the
> changed .o files to validate nothing weird has happened.

OK. 

> For struct fc_dmi_rpl, as long as "numport" is always set/validated to
> 1, I think this change is fine.

OK. I'll split this up into a small series and keep

	struct fc_fdmi_port_name	port[1];

as a one-element array.

Thanks
--
Gustavo