[PATCH v2][next] scsi: lpfc: Use struct_size() helper

[PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Gustavo A. R. Silva]

Prefer struct_size() over open-coded versions of idiom:

sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count

where count is the max number of items the flexible array is supposed to
contain.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
 - Use literal 1 in call to struct_size(), instead of rap->no_of_objects
   (Kees Cook). 

v1:
 - Link: https://lore.kernel.org/linux-hardening/99e06733f5f35c6cd62e05f530b93107bfd03362.1684358315.git.gustavoars@kernel.org/

 drivers/scsi/lpfc/lpfc_ct.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_ct.c b/drivers/scsi/lpfc/lpfc_ct.c
index e880d127d7f5..f52aeb73af8d 100644
--- a/drivers/scsi/lpfc/lpfc_ct.c
+++ b/drivers/scsi/lpfc/lpfc_ct.c
@@ -3747,9 +3747,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
 		rap->no_of_objects = cpu_to_be32(1);
 		rap->obj[0].entity_id_len = vmid->vmid_len;
 		memcpy(rap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
-		size = RAPP_IDENT_OFFSET +
-			sizeof(struct lpfc_vmid_rapp_ident_list) +
-			sizeof(struct entity_id_object);
+		size = RAPP_IDENT_OFFSET + struct_size(rap, obj, 1);
 		retry = 1;
 		break;
 
@@ -3767,9 +3765,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
 		dap->no_of_objects = cpu_to_be32(1);
 		dap->obj[0].entity_id_len = vmid->vmid_len;
 		memcpy(dap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
-		size = DAPP_IDENT_OFFSET +
-			sizeof(struct lpfc_vmid_dapp_ident_list) +
-			sizeof(struct entity_id_object);
+		size = DAPP_IDENT_OFFSET + struct_size(dap, obj, 1);
 		write_lock(&vport->vmid_lock);
 		vmid->flag &= ~LPFC_VMID_REGISTERED;
 		write_unlock(&vport->vmid_lock);
-- 
2.34.1

Re: [PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Justin Tee]

no_of_objects may be hardcoded to 1 right now, but does it make more
sense to use?

struct_size(rap, obj, be32_to_cpu(rap->no_of_objects));

We probably should have declared no_of_objects as __be32 to have
avoided this confusion.

On Tue, May 23, 2023 at 1:33 PM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> Prefer struct_size() over open-coded versions of idiom:
>
> sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count
>
> where count is the max number of items the flexible array is supposed to
> contain.
>
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
> Changes in v2:
>  - Use literal 1 in call to struct_size(), instead of rap->no_of_objects
>    (Kees Cook).
>
> v1:
>  - Link: https://lore.kernel.org/linux-hardening/99e06733f5f35c6cd62e05f530b93107bfd03362.1684358315.git.gustavoars@kernel.org/
>
>  drivers/scsi/lpfc/lpfc_ct.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/lpfc/lpfc_ct.c b/drivers/scsi/lpfc/lpfc_ct.c
> index e880d127d7f5..f52aeb73af8d 100644
> --- a/drivers/scsi/lpfc/lpfc_ct.c
> +++ b/drivers/scsi/lpfc/lpfc_ct.c
> @@ -3747,9 +3747,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
>                 rap->no_of_objects = cpu_to_be32(1);
>                 rap->obj[0].entity_id_len = vmid->vmid_len;
>                 memcpy(rap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
> -               size = RAPP_IDENT_OFFSET +
> -                       sizeof(struct lpfc_vmid_rapp_ident_list) +
> -                       sizeof(struct entity_id_object);
> +               size = RAPP_IDENT_OFFSET + struct_size(rap, obj, 1);
>                 retry = 1;
>                 break;
>
> @@ -3767,9 +3765,7 @@ lpfc_vmid_cmd(struct lpfc_vport *vport,
>                 dap->no_of_objects = cpu_to_be32(1);
>                 dap->obj[0].entity_id_len = vmid->vmid_len;
>                 memcpy(dap->obj[0].entity_id, vmid->host_vmid, vmid->vmid_len);
> -               size = DAPP_IDENT_OFFSET +
> -                       sizeof(struct lpfc_vmid_dapp_ident_list) +
> -                       sizeof(struct entity_id_object);
> +               size = DAPP_IDENT_OFFSET + struct_size(dap, obj, 1);
>                 write_lock(&vport->vmid_lock);
>                 vmid->flag &= ~LPFC_VMID_REGISTERED;
>                 write_unlock(&vport->vmid_lock);
> --
> 2.34.1
>

Re: [PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Kees Cook]

On Tue, May 23, 2023 at 10:25:20PM -0700, Justin Tee wrote:
> no_of_objects may be hardcoded to 1 right now, but does it make more
> sense to use?
> 
> struct_size(rap, obj, be32_to_cpu(rap->no_of_objects));

Oh yeah, that's nicer. :)

> We probably should have declared no_of_objects as __be32 to have
> avoided this confusion.

Perhaps this patch can add that too?

-- 
Kees Cook

Re: [PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Justin Tee]

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> > We probably should have declared no_of_objects as __be32 to have
> > avoided this confusion.
>
> Perhaps this patch can add that too?

Yes, please.  Something like this is fine:

diff --git a/drivers/scsi/lpfc/lpfc_hw.h b/drivers/scsi/lpfc/lpfc_hw.h
index 19b2d2754f32..e5a639d96122 100644
--- a/drivers/scsi/lpfc/lpfc_hw.h
+++ b/drivers/scsi/lpfc/lpfc_hw.h
@@ -1414,12 +1414,12 @@ struct app_id_object {
 };

 struct lpfc_vmid_rapp_ident_list {
-       uint32_t no_of_objects;
+       __be32 no_of_objects;
        struct entity_id_object obj[1];
 };

 struct lpfc_vmid_dapp_ident_list {
-       uint32_t no_of_objects;
+       __be32 no_of_objects;
        struct entity_id_object obj[1];
 };

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Re: [PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Martin K. Petersen]

Gustavo/Justin,

>> > We probably should have declared no_of_objects as __be32 to have
>> > avoided this confusion.
>>
>> Perhaps this patch can add that too?
>
> Yes, please.  Something like this is fine:

Please send a formal patch. Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v2][next] scsi: lpfc: Use struct_size() helper

[Justin Tee]

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Hi Martin,

Sure, will do.  I'll post the formal patch shortly.

The __be32 no_of_objects comment can be ignored for this patch as I've
already incorporated that into another patch with subject line: [PATCH
1/1] lpfc: Fix incorrect big endian type assignments in FDMI and VMID
paths

Thanks,
Justin


On Wed, May 31, 2023 at 8:27 AM Martin K. Petersen
<martin.petersen@oracle.com> wrote:
>
>
> Gustavo/Justin,
>
> >> > We probably should have declared no_of_objects as __be32 to have
> >> > avoided this confusion.
> >>
> >> Perhaps this patch can add that too?
> >
> > Yes, please.  Something like this is fine:
>
> Please send a formal patch. Thanks!
>
> --
> Martin K. Petersen      Oracle Linux Engineering

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with it, or attached to it, are confidential and are intended solely for 
the use of the individual or entity to whom it is addressed and may contain 
information that is confidential, legally privileged, protected by privacy 
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not the intended recipient or the person responsible for delivering the 
e-mail to the intended recipient, you are hereby notified that any use, 
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