This is a note to let you know that I've just added the patch titled
rtc: fix snprintf() checking in is_rtc_hctosys()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rtc-fix-snprintf-checking-in-is_rtc_hctosys.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 92220500c18634c1fedba8d59b66514696fd0c19
Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Tue May 11 10:19:26 2021 +0300
rtc: fix snprintf() checking in is_rtc_hctosys()
[ 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@xxxxxxxxxx>
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/YJov/pcGmhLi2pEl@mwanda
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/rtc/proc.c b/drivers/rtc/proc.c
index 73344598fc1b..cbcdbb19d848 100644
--- a/drivers/rtc/proc.c
+++ b/drivers/rtc/proc.c
@@ -23,8 +23,8 @@ 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);
