On Thu, 26 Oct 2023 23:53:28 +0000 Justin Stitt <justinstitt@xxxxxxxxxx> wrote: > We're doing some needless string copies when trying to assign the proper > `prop` string. We can make `prop` a const char* and simply assign to > string literals. > > For the case where a format string is used, let's allocate some memory > via kasprintf() and point prop to it. > > This also cleans up some deprecated strncpy() uses [1]. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@xxxxxxxxxxxxxxx > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> Seems reasonable to me. +CC Gwendal (+ Stephen) as it's Gwendal's driver and I think they are still actively maintaining it. > --- > Changes in v2: > - make prop a const char* and do simple assignments (thanks Jonathan) > - rebase onto 3a568e3a961ba330 > - Link to v1: https://lore.kernel.org/r/20230921-strncpy-drivers-iio-proximity-sx9324-c-v1-1-4e8d28fd1e7c@xxxxxxxxxx > --- > Note: build-tested > --- > drivers/iio/proximity/sx9324.c | 17 +++++++---------- > 1 file changed, 7 insertions(+), 10 deletions(-) > > diff --git a/drivers/iio/proximity/sx9324.c b/drivers/iio/proximity/sx9324.c > index 438f9c9aba6e..c8547035cb47 100644 > --- a/drivers/iio/proximity/sx9324.c > +++ b/drivers/iio/proximity/sx9324.c > @@ -885,7 +885,7 @@ sx9324_get_default_reg(struct device *dev, int idx, > #define SX9324_RESOLUTION_DEF "semtech,ph01-resolution" > #define SX9324_PROXRAW_DEF "semtech,ph01-proxraw-strength" > unsigned int pin_defs[SX9324_NUM_PINS]; > - char prop[] = SX9324_PROXRAW_DEF; > + const char *prop = SX9324_PROXRAW_DEF; > u32 start = 0, raw = 0, pos = 0; > int ret, count, ph, pin; > const char *res; > @@ -899,7 +899,7 @@ sx9324_get_default_reg(struct device *dev, int idx, > case SX9324_REG_AFE_PH2: > case SX9324_REG_AFE_PH3: > ph = reg_def->reg - SX9324_REG_AFE_PH0; > - snprintf(prop, ARRAY_SIZE(prop), "semtech,ph%d-pin", ph); > + prop = kasprintf(GFP_KERNEL, "semtech,ph%d-pin", ph); > > count = device_property_count_u32(dev, prop); > if (count != ARRAY_SIZE(pin_defs)) > @@ -913,6 +913,7 @@ sx9324_get_default_reg(struct device *dev, int idx, > raw |= (pin_defs[pin] << (2 * pin)) & > SX9324_REG_AFE_PH0_PIN_MASK(pin); > reg_def->def = raw; > + kfree(prop); > break; > case SX9324_REG_AFE_CTRL0: > ret = device_property_read_string(dev, > @@ -937,11 +938,9 @@ sx9324_get_default_reg(struct device *dev, int idx, > case SX9324_REG_AFE_CTRL4: > case SX9324_REG_AFE_CTRL7: > if (reg_def->reg == SX9324_REG_AFE_CTRL4) > - strncpy(prop, "semtech,ph01-resolution", > - ARRAY_SIZE(prop)); > + prop = "semtech,ph01-resolution"; > else > - strncpy(prop, "semtech,ph23-resolution", > - ARRAY_SIZE(prop)); > + prop = "semtech,ph23-resolution"; > > ret = device_property_read_u32(dev, prop, &raw); > if (ret) > @@ -1012,11 +1011,9 @@ sx9324_get_default_reg(struct device *dev, int idx, > case SX9324_REG_PROX_CTRL0: > case SX9324_REG_PROX_CTRL1: > if (reg_def->reg == SX9324_REG_PROX_CTRL0) > - strncpy(prop, "semtech,ph01-proxraw-strength", > - ARRAY_SIZE(prop)); > + prop = "semtech,ph01-proxraw-strength"; > else > - strncpy(prop, "semtech,ph23-proxraw-strength", > - ARRAY_SIZE(prop)); > + prop = "semtech,ph23-proxraw-strength"; > ret = device_property_read_u32(dev, prop, &raw); > if (ret) > break; > > --- > base-commit: 3a568e3a961ba330091cd031647e4c303fa0badb > change-id: 20230921-strncpy-drivers-iio-proximity-sx9324-c-8c3437676039 > > Best regards, > -- > Justin Stitt <justinstitt@xxxxxxxxxx> >
