From: Len Baker <len.baker@gmx.com>
To: Simon Horman <simon.horman@corigine.com>,
Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Cc: Len Baker <len.baker@gmx.com>, Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
oss-drivers@corigine.com, netdev@vger.kernel.org,
linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] nfp: Prefer struct_size over open coded arithmetic
Date: Sun, 12 Sep 2021 15:10:57 +0200 [thread overview]
Message-ID: <20210912131057.2285-1-len.baker@gmx.com> (raw)
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(-)
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
next reply other threads:[~2021-09-12 13:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-12 13:10 Len Baker [this message]
2021-09-12 19:07 ` [PATCH] nfp: Prefer struct_size over open coded arithmetic Gustavo A. R. Silva
2021-09-13 8:31 ` Simon Horman
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