| Message ID | 20210911112716.10067-1-len.baker@gmx.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Input: omap-keypad - prefer struct_size over open coded arithmetic | expand |
On 9/11/21 06:27, 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> Thanks -- Gustavo > --- > drivers/input/keyboard/omap-keypad.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/input/keyboard/omap-keypad.c b/drivers/input/keyboard/omap-keypad.c > index dbe836c7ff47..eb3a687796e7 100644 > --- a/drivers/input/keyboard/omap-keypad.c > +++ b/drivers/input/keyboard/omap-keypad.c > @@ -190,8 +190,7 @@ static int omap_kp_probe(struct platform_device *pdev) > row_shift = get_count_order(pdata->cols); > keycodemax = pdata->rows << row_shift; > > - omap_kp = kzalloc(sizeof(struct omap_kp) + > - keycodemax * sizeof(unsigned short), GFP_KERNEL); > + omap_kp = kzalloc(struct_size(omap_kp, keymap, keycodemax), GFP_KERNEL); > input_dev = input_allocate_device(); > if (!omap_kp || !input_dev) { > kfree(omap_kp); > -- > 2.25.1 > > > >
diff --git a/drivers/input/keyboard/omap-keypad.c b/drivers/input/keyboard/omap-keypad.c index dbe836c7ff47..eb3a687796e7 100644 --- a/drivers/input/keyboard/omap-keypad.c +++ b/drivers/input/keyboard/omap-keypad.c @@ -190,8 +190,7 @@ static int omap_kp_probe(struct platform_device *pdev) row_shift = get_count_order(pdata->cols); keycodemax = pdata->rows << row_shift; - omap_kp = kzalloc(sizeof(struct omap_kp) + - keycodemax * sizeof(unsigned short), GFP_KERNEL); + omap_kp = kzalloc(struct_size(omap_kp, keymap, keycodemax), GFP_KERNEL); input_dev = input_allocate_device(); if (!omap_kp || !input_dev) { kfree(omap_kp);
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/input/keyboard/omap-keypad.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 2.25.1