| Message ID | 20210905144054.5124-1-len.baker@gmx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | i3c/master/mipi-i3c-hci: Prefer struct_size over open coded arithmetic | expand |
On Sun, 5 Sep 2021, 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> Acked-by: Nicolas Pitre <npitre@baylibre.com> > --- > drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c > index af873a9be050..2990ac9eaade 100644 > --- a/drivers/i3c/master/mipi-i3c-hci/dma.c > +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c > @@ -223,7 +223,7 @@ static int hci_dma_init(struct i3c_hci *hci) > } > if (nr_rings > XFER_RINGS) > nr_rings = XFER_RINGS; > - rings = kzalloc(sizeof(*rings) + nr_rings * sizeof(*rh), GFP_KERNEL); > + rings = kzalloc(struct_size(rings, headers, nr_rings), GFP_KERNEL); > if (!rings) > return -ENOMEM; > hci->io_data = rings; > -- > 2.25.1 > >
On Sun, 5 Sep 2021 16:40:54 +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. > > [...] Applied, thanks! [1/1] i3c/master/mipi-i3c-hci: Prefer struct_size over open coded arithmetic commit: 605fa23646dd9a86c4300e1719542a865111d1b6 Best regards,
diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c index af873a9be050..2990ac9eaade 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dma.c +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c @@ -223,7 +223,7 @@ static int hci_dma_init(struct i3c_hci *hci) } if (nr_rings > XFER_RINGS) nr_rings = XFER_RINGS; - rings = kzalloc(sizeof(*rings) + nr_rings * sizeof(*rh), GFP_KERNEL); + rings = kzalloc(struct_size(rings, headers, nr_rings), GFP_KERNEL); if (!rings) return -ENOMEM; hci->io_data = rings;
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/i3c/master/mipi-i3c-hci/dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.25.1