Re: [PATCH] tty: serial: return appropriate error on failure

From: Jiri Slaby
Date: Wed Dec 08 2021 - 00:44:59 EST


On 07. 12. 21, 23:17, Vihas Mak wrote:
when a user with CAP_SYS_ADMIN disabled calls ioctl (TIOCSSERIAL),
uart_set_info() returns 0 instead of -EPERM and the user remains unware
about what went wrong. Fix this.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215205

Signed-off-by: Vihas Mak <makvihas@xxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 61e3dd022..c204bdecc 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -960,7 +960,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
uport->fifosize = new_info->xmit_fifo_size;
check_and_exit:
- retval = 0;
+ retval = retval < 0 ? retval : 0;

This is wrong IMO. See:
https://bugzilla.kernel.org/show_bug.cgi?id=215205#c1

if (uport->type == PORT_UNKNOWN)
goto exit;
if (tty_port_initialized(port)) {



--
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