From 1481ecf1941a35a3e82d0f3e8fe9a2bdce28ee6f Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 17 Jul 2018 10:58:10 +0200 Subject: [PATCH] serial: sh-sci: Fix use-after-free on subsequent port startup sci_request_irq() checks port->irqstr[j] for a NULL pointer, to decide if a fallback interrupt name string should be allocated or not. While this string is freed during port shutdown, the pointer is not zeroed. Hence on a subsequent startup of the port, it will still be pointing to the freed memory, leading to e.g. WARNING: CPU: 0 PID: 404 at fs/proc/generic.c:388 __proc_create+0xbc/0x260 name len 0 or to a crash (the latter is more likely with CONFIG_DEBUG_SLAB=y, due to the poisoning of freed memory). Instead of zeroeing the pointer at multiple places, preinitialize port->irqstr[j] to zero to fix this. Fixes: 8b0bbd956228ae87 ("serial: sh-sci: Add support for R7S9210") Signed-off-by: Geert Uytterhoeven Reviewed-by: Ulrich Hecht Reviewed-by: Simon Horman Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 5808edfe3f7b..f8e53ac5c17d 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1872,6 +1872,7 @@ static int sci_request_irq(struct sci_port *port) } desc = sci_irq_desc + i; + port->irqstr[j] = NULL; if (SCIx_TEIDRI_IRQ_EXISTS(port)) { /* * ERI and BRI are muxed, just register ERI and