From 756d5282bf04db868b1c0b93f41981dabe2af57f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Sat, 10 Mar 2018 00:27:35 -0600 Subject: [PATCH] rtc: s5m: Remove VLA usage 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 Reviewed-by: Krzysztof Kozlowski Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-s5m.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c index 4c363deb79fd..8428455432ca 100644 --- a/drivers/rtc/rtc-s5m.c +++ b/drivers/rtc/rtc-s5m.c @@ -47,6 +47,8 @@ enum { RTC_MONTH, RTC_YEAR1, RTC_YEAR2, + /* Make sure this is always the last enum name. */ + RTC_MAX_NUM_TIME_REGS }; /* @@ -378,7 +380,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; int ret; if (info->regs->read_time_udr_mask) { @@ -424,7 +426,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; int ret = 0; switch (info->device_type) { @@ -461,7 +463,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; unsigned int val; int ret, i; @@ -511,7 +513,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; int ret, i; struct rtc_time tm; @@ -556,7 +558,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; u8 alarm0_conf; struct rtc_time tm; @@ -609,7 +611,7 @@ 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[RTC_MAX_NUM_TIME_REGS]; int ret; switch (info->device_type) {