From: Miaoqian Lin <linmq006@gmail.com>
To: "David S. Miller" <davem@davemloft.net>,
Andreas Larsson <andreas@gaisler.com>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Lars Kotthoff <metalhead@metalhead.ws>,
sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: linmq006@gmail.com, stable@vger.kernel.org
Subject: [PATCH] sparc/led: prevent buffer underflow on zero-length write
Date: Thu, 30 Oct 2025 15:21:53 +0800 [thread overview]
Message-ID: <20251030072156.30656-1-linmq006@gmail.com> (raw)
Fix out-of-bounds access in led_proc_write() when count is 0.
Accessing buf[count - 1] with count=0 reads/writes buf[-1].
Check for count==0 and return -EINVAL early to fix this.
Found via static analysis and code review.
Fixes: ee1858d3122d ("[SPARC]: Add sun4m LED driver.")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
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..aa0ca0d8d0e2 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 == 0)
+ return -EINVAL;
+
if (count > LED_MAX_LENGTH)
count = LED_MAX_LENGTH;
--
2.39.5 (Apple Git-154)
next reply other threads:[~2025-10-30 7:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-30 7:21 Miaoqian Lin [this message]
2026-01-14 8:40 ` Andreas Larsson
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