| Message ID | 20210912131057.2285-1-len.baker@gmx.com |
|---|---|
| State | New |
| Headers | show |
| Series | nfp: Prefer struct_size over open coded arithmetic | expand |
On Sun, Sep 12, 2021 at 03:10:57PM +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. > > So, use the struct_size() helper to do the arithmetic instead of the > argument "size + count * size" in the kzalloc() function. > > [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: Gustavo A. R. Silva <gustavoars@kernel.org> I'll take this in my -next tree. :) Thanks, Len. -- Gustavo > --- > drivers/net/ethernet/netronome/nfp/nfp_net_repr.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > index 3b8e675087de..369f6ae700c7 100644 > --- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > @@ -499,8 +499,7 @@ struct nfp_reprs *nfp_reprs_alloc(unsigned int num_reprs) > { > struct nfp_reprs *reprs; > > - reprs = kzalloc(sizeof(*reprs) + > - num_reprs * sizeof(struct net_device *), GFP_KERNEL); > + reprs = kzalloc(struct_size(reprs, reprs, num_reprs), GFP_KERNEL); > if (!reprs) > return NULL; > reprs->num_reprs = num_reprs; > -- > 2.25.1 >
On Sun, Sep 12, 2021 at 03:10:57PM +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. > > So, use the struct_size() helper to do the arithmetic instead of the > argument "size + count * size" in the kzalloc() function. > > [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: Simon Horman <simon.horman@corigine.com> > --- > drivers/net/ethernet/netronome/nfp/nfp_net_repr.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > index 3b8e675087de..369f6ae700c7 100644 > --- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c > @@ -499,8 +499,7 @@ struct nfp_reprs *nfp_reprs_alloc(unsigned int num_reprs) > { > struct nfp_reprs *reprs; > > - reprs = kzalloc(sizeof(*reprs) + > - num_reprs * sizeof(struct net_device *), GFP_KERNEL); > + reprs = kzalloc(struct_size(reprs, reprs, num_reprs), GFP_KERNEL); > if (!reprs) > return NULL; > reprs->num_reprs = num_reprs; > -- > 2.25.1 >
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c index 3b8e675087de..369f6ae700c7 100644 --- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c @@ -499,8 +499,7 @@ struct nfp_reprs *nfp_reprs_alloc(unsigned int num_reprs) { struct nfp_reprs *reprs; - reprs = kzalloc(sizeof(*reprs) + - num_reprs * sizeof(struct net_device *), GFP_KERNEL); + reprs = kzalloc(struct_size(reprs, reprs, num_reprs), GFP_KERNEL); if (!reprs) return NULL; reprs->num_reprs = num_reprs;
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. So, use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the kzalloc() function. [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/net/ethernet/netronome/nfp/nfp_net_repr.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 2.25.1