[PATCH] serial: sifive: fix off-by-one in console port bounds check

[PATCH] serial: sifive: fix off-by-one in console port bounds check

[Zongmin Zhou]

From: Zongmin Zhou <zhouzongmin@kylinos.cn>

sifive_serial_console_ports[] is sized SIFIVE_SERIAL_MAX_PORTS (8), so
valid indices are 0..7. The bounds check in sifive_serial_probe() uses
"id > SIFIVE_SERIAL_MAX_PORTS", which lets id == 8 pass and causes an
out-of-bounds write in __ssp_add_console_port() through
sifive_serial_console_ports[ssp->port.line].

Fix the check to use >= instead, matching the check already used in
sifive_serial_console_setup().

Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART")
Signed-off-by: Zongmin Zhou <zhouzongmin@kylinos.cn>
---
 drivers/tty/serial/sifive.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 110d676..5d76f04 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -999,7 +999,7 @@ static int sifive_serial_probe(struct platform_device *pdev)
 	}
 
 #ifdef CONFIG_SERIAL_SIFIVE_CONSOLE
-	if (id > SIFIVE_SERIAL_MAX_PORTS) {
+	if (id >= SIFIVE_SERIAL_MAX_PORTS) {
 		dev_err(&pdev->dev, "too many UARTs (%d)\n", id);
 		return -EINVAL;
 	}
-- 
2.34.1


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Re: [PATCH] serial: sifive: fix off-by-one in console port bounds check

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (fixes)
by Greg Kroah-Hartman <gregkh@linuxfoundation.org>:

On Thu, 27 Aug 2026 09:45:24 +0800 you wrote:
> From: Zongmin Zhou <zhouzongmin@kylinos.cn>
> 
> sifive_serial_console_ports[] is sized SIFIVE_SERIAL_MAX_PORTS (8), so
> valid indices are 0..7. The bounds check in sifive_serial_probe() uses
> "id > SIFIVE_SERIAL_MAX_PORTS", which lets id == 8 pass and causes an
> out-of-bounds write in __ssp_add_console_port() through
> sifive_serial_console_ports[ssp->port.line].
> 
> [...]

Here is the summary with links:
  - serial: sifive: fix off-by-one in console port bounds check
    https://git.kernel.org/riscv/c/bf961847813d

You are awesome, thank you!
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