* [PATCH] drivers/serial/serial_core.c: prevent reading uninitialized stack memory
@ 2010-09-15 21:44 Dan Rosenberg
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From: Dan Rosenberg @ 2010-09-15 21:44 UTC (permalink / raw)
To: gregkh; +Cc: linux-kernel, security
The TIOCGICOUNT device ioctl allows unprivileged users to read
uninitialized stack memory, because the "reserved" member of the
serial_icounter_struct struct declared on the stack is not altered or
zeroed before being copied back to the user. This patch takes care of
it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
--- linux-2.6.35.4.orig/drivers/serial/serial_core.c 2010-08-26 19:47:12.000000000 -0400
+++ linux-2.6.35.4/drivers/serial/serial_core.c 2010-09-15 13:57:04.767375072 -0400
@@ -1081,6 +1081,8 @@ static int uart_get_count(struct uart_st
struct uart_icount cnow;
struct uart_port *uport = state->uart_port;
+ memset(&icount, 0, sizeof(struct serial_icounter_struct));
+
spin_lock_irq(&uport->lock);
memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
spin_unlock_irq(&uport->lock);
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