From: Dan Carpenter dan.carpenter@oracle.com
stable inclusion from linux-4.19.198 commit 1cae2aece5bc508d4a9fc29764669930528fefbc
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[ Upstream commit 54b909436ede47e0ee07f1765da27ec2efa41e84 ]
The scnprintf() function silently truncates the printf() and returns the number bytes that it was able to copy (not counting the NUL terminator). Thus, the highest value it can return here is "NAME_SIZE - 1" and the overflow check is dead code. Fix this by using the snprintf() function which returns the number of bytes that would have been copied if there was enough space and changing the condition from "> NAME_SIZE" to ">= NAME_SIZE".
Fixes: 92589c986b33 ("rtc-proc: permit the /proc/driver/rtc device to use other devices") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Link: https://lore.kernel.org/r/YJov/pcGmhLi2pEl@mwanda Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/rtc/rtc-proc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/rtc-proc.c b/drivers/rtc/rtc-proc.c index a9dd9218fae21..b8c5b93102ce9 100644 --- a/drivers/rtc/rtc-proc.c +++ b/drivers/rtc/rtc-proc.c @@ -26,8 +26,8 @@ static bool is_rtc_hctosys(struct rtc_device *rtc) int size; char name[NAME_SIZE];
- size = scnprintf(name, NAME_SIZE, "rtc%d", rtc->id); - if (size > NAME_SIZE) + size = snprintf(name, NAME_SIZE, "rtc%d", rtc->id); + if (size >= NAME_SIZE) return false;
return !strncmp(name, CONFIG_RTC_HCTOSYS_DEVICE, NAME_SIZE);