On Thu, Mar 8, 2018 at 9:20 AM, Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> wrote: > In preparation to enabling -Wvla, remove VLAs and replace them > with fixed-length arrays instead. > > From a security viewpoint, the use of Variable Length Arrays can be > a vector for stack overflow attacks. Also, in general, as the code > evolves it is easy to lose track of how big a VLA can get. Thus, we > can end up having segfaults that are hard to debug. > > Also, fixed as part of the directive to remove all VLAs from > the kernel: https://lkml.org/lkml/2018/3/7/621 > > Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> > --- > drivers/rtc/rtc-s5m.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c > index 6deae10..2b5f4f7 100644 > --- a/drivers/rtc/rtc-s5m.c > +++ b/drivers/rtc/rtc-s5m.c > @@ -38,6 +38,9 @@ > */ > #define UDR_READ_RETRY_CNT 5 > > +/* Maximum number of registers for setting time/alarm0/alarm1 */ > +#define MAX_NUM_TIME_REGS 8 I would adjust the various const struct s5m_rtc_reg_config's .regs_count to be represented by this new define, so the stack and the structures stay in sync. Something like: static const struct s5m_rtc_reg_config s2mps13_rtc_regs = { .regs_count = MAX_NUM_TIME_REGS - 1, ? -Kees > + > /* > * Registers used by the driver which are different between chipsets. > * > @@ -367,7 +370,7 @@ static void s5m8763_tm_to_data(struct rtc_time *tm, u8 *data) > static int s5m_rtc_read_time(struct device *dev, struct rtc_time *tm) > { > struct s5m_rtc_info *info = dev_get_drvdata(dev); > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > int ret; > > if (info->regs->read_time_udr_mask) { > @@ -413,7 +416,7 @@ static int s5m_rtc_read_time(struct device *dev, struct rtc_time *tm) > static int s5m_rtc_set_time(struct device *dev, struct rtc_time *tm) > { > struct s5m_rtc_info *info = dev_get_drvdata(dev); > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > int ret = 0; > > switch (info->device_type) { > @@ -450,7 +453,7 @@ static int s5m_rtc_set_time(struct device *dev, struct rtc_time *tm) > static int s5m_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) > { > struct s5m_rtc_info *info = dev_get_drvdata(dev); > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > unsigned int val; > int ret, i; > > @@ -500,7 +503,7 @@ static int s5m_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) > > static int s5m_rtc_stop_alarm(struct s5m_rtc_info *info) > { > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > int ret, i; > struct rtc_time tm; > > @@ -545,7 +548,7 @@ static int s5m_rtc_stop_alarm(struct s5m_rtc_info *info) > static int s5m_rtc_start_alarm(struct s5m_rtc_info *info) > { > int ret; > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > u8 alarm0_conf; > struct rtc_time tm; > > @@ -598,7 +601,7 @@ static int s5m_rtc_start_alarm(struct s5m_rtc_info *info) > static int s5m_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) > { > struct s5m_rtc_info *info = dev_get_drvdata(dev); > - u8 data[info->regs->regs_count]; > + u8 data[MAX_NUM_TIME_REGS]; > int ret; > > switch (info->device_type) { > -- > 2.7.4 > -- Kees Cook Pixel Security -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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