> -----Original Message----- > From: Len Baker <len.baker@xxxxxxx> > Sent: Saturday, September 11, 2021 6:28 AM > To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang > <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; > Wei Liu <wei.liu@xxxxxxxxxx>; Dexuan Cui <decui@xxxxxxxxxxxxx>; David S. > Miller <davem@xxxxxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Sumit > Semwal <sumit.semwal@xxxxxxxxxx>; Christian König > <christian.koenig@xxxxxxx>; Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Len Baker <len.baker@xxxxxxx>; Colin Ian King > <colin.king@xxxxxxxxxxxxx>; linux-hardening@xxxxxxxxxxxxxxx; linux- > hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; linux-media@xxxxxxxxxxxxxxx; dri- > devel@xxxxxxxxxxxxxxxxxxxxx; linaro-mm-sig@xxxxxxxxxxxxxxxx > Subject: [PATCH] net: mana: Prefer struct_size over open coded > arithmetic > > [Some people who received this message don't often get email from > len.baker@xxxxxxx. Learn why this is important at > http://aka.ms/LearnAboutSenderIdentification.] > > 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://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ke > rnel.org%2Fdoc%2Fhtml%2Fv5.14%2Fprocess%2Fdeprecated.html%23open-coded- > arithmetic-in-allocator- > arguments&data=04%7C01%7Chaiyangz%40microsoft.com%7C1bf83c1204a34dae > a6d308d9750eef16%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6376695297 > 12931146%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ > BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=PbYpBtyYfVfwwlxWSQx%2FiARc9 > mhb0J7bfD46%2F9q5oTw%3D&reserved=0 > > Signed-off-by: Len Baker <len.baker@xxxxxxx> > --- > drivers/net/ethernet/microsoft/mana/hw_channel.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c > b/drivers/net/ethernet/microsoft/mana/hw_channel.c > index 1a923fd99990..0efdc6c3c32a 100644 > --- a/drivers/net/ethernet/microsoft/mana/hw_channel.c > +++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c > @@ -398,9 +398,7 @@ static int mana_hwc_alloc_dma_buf(struct > hw_channel_context *hwc, u16 q_depth, > int err; > u16 i; > > - dma_buf = kzalloc(sizeof(*dma_buf) + > - q_depth * sizeof(struct hwc_work_request), > - GFP_KERNEL); > + dma_buf = kzalloc(struct_size(dma_buf, reqs, q_depth), > GFP_KERNEL); Thanks! Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
