34 lines
1.4 KiB
Diff
34 lines
1.4 KiB
Diff
From: David Howells <dhowells@redhat.com>
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Date: Wed, 5 Apr 2017 17:40:31 +0100
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Subject: [60/61] Lock down TIOCSSERIAL
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Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=3f0d5eb601c66451afebe889623bcbafec0e4bb8
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Lock down TIOCSSERIAL as that can be used to change the ioport and irq
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settings on a serial port. This only appears to be an issue for the serial
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drivers that use the core serial code. All other drivers seem to either
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ignore attempts to change port/irq or give an error.
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Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: David Howells <dhowells@redhat.com>
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---
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drivers/tty/serial/serial_core.c | 6 ++++++
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1 file changed, 6 insertions(+)
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diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
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index 3fe56894974a..4181b0004de9 100644
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--- a/drivers/tty/serial/serial_core.c
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+++ b/drivers/tty/serial/serial_core.c
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@@ -821,6 +821,12 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
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new_flags = new_info->flags;
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old_custom_divisor = uport->custom_divisor;
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+ if ((change_port || change_irq) && kernel_is_locked_down()) {
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+ pr_err("Using TIOCSSERIAL to change device addresses, irqs and dma channels is not permitted when the kernel is locked down\n");
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+ retval = -EPERM;
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+ goto exit;
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+ }
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+
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if (!capable(CAP_SYS_ADMIN)) {
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retval = -EPERM;
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if (change_irq || change_port ||
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