[PATCH 2/4] sparc: led: reject zero-length proc writes
Pengpeng Hou <[email protected]>
| Newsgroups | gmane.linux.ports.sparc,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
led_proc_write() passes count straight through memdup_user_nul() and then
unconditionally inspects buf[count - 1] to strip a trailing newline. A
zero-length write therefore dereferences one byte before the allocated
buffer.
Reject empty writes before touching buf[count - 1].
Fixes: ee1858d3122d ("[SPARC]: Add sun4m LED driver.")
Signed-off-by: Pengpeng Hou <[email protected]>
---
arch/sparc/kernel/led.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/sparc/kernel/led.c b/arch/sparc/kernel/led.c
index f4fb82b019bb..b9758fdbc054 100644
--- a/arch/sparc/kernel/led.c
+++ b/arch/sparc/kernel/led.c
@@ -70,6 +70,9 @@ static ssize_t led_proc_write(struct file *file, const char __user *buffer,
{
char *buf = NULL;
+ if (!count)
+ return -EINVAL;
+
if (count > LED_MAX_LENGTH)
count = LED_MAX_LENGTH;
--
2.50.1 (Apple Git-155)