On Sat, Aug 14, 2021 at 4:55 PM Len Baker <len.baker@xxxxxxx> wrote: > > strcpy() performs no bounds checking on the destination buffer. This > could result in linear overflows beyond the end of the buffer, leading > to all kinds of misbehaviors. So, remove all the uses and add > devm_kstrdup() or devm_kasprintf() instead. > > This patch is an effort to clean up the proliferation of str*() > functions in the kernel and a previous step in the path to remove > the strcpy function from the kernel entirely [1]. > > [1] https://github.com/KSPP/linux/issues/88 Thank you very much for doing this! Now I like the result, Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > Signed-off-by: Len Baker <len.baker@xxxxxxx> > --- > The previous versions can be found in: > > v1 > https://lore.kernel.org/linux-hardening/20210801171157.17858-1-len.baker@xxxxxxx/ > > v2 > https://lore.kernel.org/linux-hardening/20210807152225.9403-1-len.baker@xxxxxxx/ > > v3 > https://lore.kernel.org/linux-hardening/20210814090618.8920-1-len.baker@xxxxxxx/ > > Changelog v1 -> v2 > - Modify the commit changelog to inform that the motivation of this > patch is to remove the strcpy() function from the kernel entirely > (Jonathan Cameron). > > Changelog v2 -> v3 > - Rewrite the code using devm_kstrdup() and devm_kasprintf() functions > (Andy Shevchenko). > - Rebase against v5.14-rc5. > > Changelog v3 -> v4 > - Reorder the variables (Andy Shevchenko). > - Get the device in the definition block (Andy Shevchenko). > - Reword the comment (Andy Shevchenko). > - Change the conditions in the "if" statement to clarify the "0" check > (Andy Shevchenko). > > drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c | 30 +++++++++++++--------- > 1 file changed, 18 insertions(+), 12 deletions(-) > > diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c > index f282e9cc34c5..7eceae0012c9 100644 > --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c > +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c > @@ -261,6 +261,7 @@ int inv_mpu_magn_set_rate(const struct inv_mpu6050_state *st, int fifo_rate) > */ > int inv_mpu_magn_set_orient(struct inv_mpu6050_state *st) > { > + struct device *dev = regmap_get_device(st->map); > const char *orient; > char *str; > int i; > @@ -281,19 +282,24 @@ int inv_mpu_magn_set_orient(struct inv_mpu6050_state *st) > /* z <- -z */ > for (i = 0; i < 3; ++i) { > orient = st->orientation.rotation[6 + i]; > - /* use length + 2 for adding minus sign if needed */ > - str = devm_kzalloc(regmap_get_device(st->map), > - strlen(orient) + 2, GFP_KERNEL); > - if (str == NULL) > + > + /* > + * The value is negated according to one of the following > + * rules: > + * > + * 1) Drop leading minus. > + * 2) Leave 0 as is. > + * 3) Add leading minus. > + */ > + if (orient[0] == '-') > + str = devm_kstrdup(dev, orient + 1, GFP_KERNEL); > + else if (orient[0] == '0' && orient[1] == '\0') > + str = devm_kstrdup(dev, orient, GFP_KERNEL); > + else > + str = devm_kasprintf(dev, GFP_KERNEL, "-%s", orient); > + if (!str) > return -ENOMEM; > - if (strcmp(orient, "0") == 0) { > - strcpy(str, orient); > - } else if (orient[0] == '-') { > - strcpy(str, &orient[1]); > - } else { > - str[0] = '-'; > - strcpy(&str[1], orient); > - } > + > st->magn_orient.rotation[6 + i] = str; > } > break; > -- > 2.25.1 > -- With Best Regards, Andy Shevchenko
