github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 10:09:10 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

sparc: led: avoid trimming a newline from empty writes

Browse Source 
led_proc_write() duplicates up to LED_MAX_LENGTH bytes with
memdup_user_nul() and then unconditionally inspects buf[count - 1] to
strip a trailing newline. A zero-length write therefore reads one byte
before the duplicated buffer.

The previous version rejected empty writes, but empty input already falls
through to the existing default case and turns the LED off like any other
unrecognized string. Preserve that behavior and only skip the newline
trim when there is no input byte to inspect.

Fixes: ee1858d312 ("[SPARC]: Add sun4m LED driver.")
Suggested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
This commit is contained in:
Pengpeng Hou 2026-06-15 13:58:50 +08:00 committed by Andreas Larsson
parent 2416b30ec2
commit 7eb475e8a7
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/sparc/kernel/led.c
View File

@ -78,7 +78,7 @@ static ssize_t led_proc_write(struct file *file, const char __user *buffer,
return PTR_ERR(buf);
/* work around \n when echo'ing into proc */
if (buf[count - 1] == '\n')
if (count > 0 && buf[count - 1] == '\n')
buf[count - 1] = '\0';
/* before we change anything we want to stop any running timers,