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* [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic
@ 2021-09-05  8:18 Len Baker
  2021-09-05 10:21 ` Leon Romanovsky
  2021-09-08 11:44 ` Jason Gunthorpe
  0 siblings, 2 replies; 4+ messages in thread
From: Len Baker @ 2021-09-05  8:18 UTC (permalink / raw)
  To: Selvin Xavier, Naresh Kumar PBS, Doug Ledford, Jason Gunthorpe
  Cc: Len Baker, Kees Cook, linux-rdma, linux-hardening, linux-kernel

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

In this case this is not actually dynamic sizes: both sides of the
multiplication are constant values. However it is best to refactor this
anyway, just to keep the open-coded math idiom out of code.

So, use the purpose specific kcalloc() function instead of the argument
size * count in the kzalloc() function.

Also, remove the unnecessary initialization of the sqp_tbl variable
since it is set a few lines later.

[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Signed-off-by: Len Baker <len.baker@gmx.com>
---
 drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/bnxt_re/ib_verbs.c b/drivers/infiniband/hw/bnxt_re/ib_verbs.c
index ea0054c60fbc..6fd4b87832b4 100644
--- a/drivers/infiniband/hw/bnxt_re/ib_verbs.c
+++ b/drivers/infiniband/hw/bnxt_re/ib_verbs.c
@@ -1312,7 +1312,7 @@ static int bnxt_re_init_qp_attr(struct bnxt_re_qp *qp, struct bnxt_re_pd *pd,
 static int bnxt_re_create_shadow_gsi(struct bnxt_re_qp *qp,
 				     struct bnxt_re_pd *pd)
 {
-	struct bnxt_re_sqp_entries *sqp_tbl = NULL;
+	struct bnxt_re_sqp_entries *sqp_tbl;
 	struct bnxt_re_dev *rdev;
 	struct bnxt_re_qp *sqp;
 	struct bnxt_re_ah *sah;
@@ -1320,7 +1320,7 @@ static int bnxt_re_create_shadow_gsi(struct bnxt_re_qp *qp,

 	rdev = qp->rdev;
 	/* Create a shadow QP to handle the QP1 traffic */
-	sqp_tbl = kzalloc(sizeof(*sqp_tbl) * BNXT_RE_MAX_GSI_SQP_ENTRIES,
+	sqp_tbl = kcalloc(BNXT_RE_MAX_GSI_SQP_ENTRIES, sizeof(*sqp_tbl),
 			  GFP_KERNEL);
 	if (!sqp_tbl)
 		return -ENOMEM;
--
2.25.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic
  2021-09-05  8:18 [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic Len Baker
@ 2021-09-05 10:21 ` Leon Romanovsky
  2021-09-07 14:12   ` Selvin Xavier
  2021-09-08 11:44 ` Jason Gunthorpe
  1 sibling, 1 reply; 4+ messages in thread
From: Leon Romanovsky @ 2021-09-05 10:21 UTC (permalink / raw)
  To: Len Baker
  Cc: Selvin Xavier, Naresh Kumar PBS, Doug Ledford, Jason Gunthorpe,
	Kees Cook, linux-rdma, linux-hardening, linux-kernel

On Sun, Sep 05, 2021 at 10:18:12AM +0200, Len Baker wrote:
> As noted in the "Deprecated Interfaces, Language Features, Attributes,
> and Conventions" documentation [1], size calculations (especially
> multiplication) should not be performed in memory allocator (or similar)
> function arguments due to the risk of them overflowing. This could lead
> to values wrapping around and a smaller allocation being made than the
> caller was expecting. Using those allocations could lead to linear
> overflows of heap memory and other misbehaviors.
> 
> In this case this is not actually dynamic sizes: both sides of the
> multiplication are constant values. However it is best to refactor this
> anyway, just to keep the open-coded math idiom out of code.
> 
> So, use the purpose specific kcalloc() function instead of the argument
> size * count in the kzalloc() function.
> 
> Also, remove the unnecessary initialization of the sqp_tbl variable
> since it is set a few lines later.
> 
> [1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> 
> Signed-off-by: Len Baker <len.baker@gmx.com>
> ---
>  drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic
  2021-09-05 10:21 ` Leon Romanovsky
@ 2021-09-07 14:12   ` Selvin Xavier
  0 siblings, 0 replies; 4+ messages in thread
From: Selvin Xavier @ 2021-09-07 14:12 UTC (permalink / raw)
  To: Leon Romanovsky
  Cc: Len Baker, Naresh Kumar PBS, Doug Ledford, Jason Gunthorpe,
	Kees Cook, linux-rdma, linux-hardening, linux-kernel

[-- Attachment #1: Type: text/plain, Size: 1494 bytes --]

On Sun, Sep 5, 2021 at 3:51 PM Leon Romanovsky <leon@kernel.org> wrote:
>
> On Sun, Sep 05, 2021 at 10:18:12AM +0200, Len Baker wrote:
> > As noted in the "Deprecated Interfaces, Language Features, Attributes,
> > and Conventions" documentation [1], size calculations (especially
> > multiplication) should not be performed in memory allocator (or similar)
> > function arguments due to the risk of them overflowing. This could lead
> > to values wrapping around and a smaller allocation being made than the
> > caller was expecting. Using those allocations could lead to linear
> > overflows of heap memory and other misbehaviors.
> >
> > In this case this is not actually dynamic sizes: both sides of the
> > multiplication are constant values. However it is best to refactor this
> > anyway, just to keep the open-coded math idiom out of code.
> >
> > So, use the purpose specific kcalloc() function instead of the argument
> > size * count in the kzalloc() function.
> >
> > Also, remove the unnecessary initialization of the sqp_tbl variable
> > since it is set a few lines later.
> >
> > [1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> >
> > Signed-off-by: Len Baker <len.baker@gmx.com>
> > ---
> >  drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
>
> Thanks,
> Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic
  2021-09-05  8:18 [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic Len Baker
  2021-09-05 10:21 ` Leon Romanovsky
@ 2021-09-08 11:44 ` Jason Gunthorpe
  1 sibling, 0 replies; 4+ messages in thread
From: Jason Gunthorpe @ 2021-09-08 11:44 UTC (permalink / raw)
  To: Len Baker
  Cc: Selvin Xavier, Naresh Kumar PBS, Doug Ledford, Kees Cook,
	linux-rdma, linux-hardening, linux-kernel

On Sun, Sep 05, 2021 at 10:18:12AM +0200, Len Baker wrote:
> As noted in the "Deprecated Interfaces, Language Features, Attributes,
> and Conventions" documentation [1], size calculations (especially
> multiplication) should not be performed in memory allocator (or similar)
> function arguments due to the risk of them overflowing. This could lead
> to values wrapping around and a smaller allocation being made than the
> caller was expecting. Using those allocations could lead to linear
> overflows of heap memory and other misbehaviors.
> 
> In this case this is not actually dynamic sizes: both sides of the
> multiplication are constant values. However it is best to refactor this
> anyway, just to keep the open-coded math idiom out of code.
> 
> So, use the purpose specific kcalloc() function instead of the argument
> size * count in the kzalloc() function.
> 
> Also, remove the unnecessary initialization of the sqp_tbl variable
> since it is set a few lines later.
> 
> [1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> 
> Signed-off-by: Len Baker <len.baker@gmx.com>
> Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
> Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
> ---
>  drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied to for-rc, thanks

Jason

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-09-08 11:44 UTC | newest]

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2021-09-05  8:18 [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic Len Baker
2021-09-05 10:21 ` Leon Romanovsky
2021-09-07 14:12   ` Selvin Xavier
2021-09-08 11:44 ` Jason Gunthorpe

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