Commit 7127d243 authored Apr 17, 2020 by Jiri Slaby Committed by Greg Kroah-Hartman Apr 23, 2020

tty: rocket, avoid OOB access



init_r_port can access pc104 array out of bounds. pc104 is a 2D array
defined to have 4 members. Each member has 8 submembers.
* we can have more than 4 (PCI) boards, i.e. [board] can be OOB
* line is not modulo-ed by anything, so the first line on the second
  board can be 4, on the 3rd 12 or alike (depending on previously
  registered boards). It's zero only on the first line of the first
  board. So even [line] can be OOB, quite soon (with the 2nd registered
  board already).

This code is broken for ages, so just avoid the OOB accesses and don't
try to fix it as we would need to find out the correct line number. Use
the default: RS232, if we are out.

Generally, if anyone needs to set the interface types, a module parameter
is past the last thing that should be used for this purpose. The
parameters' description says it's for ISA cards anyway.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20200417105959.15201-2-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 580d952e

drivers/tty/rocket.c

+14 −11

Original line number	Diff line number	Diff line
		@@ -632,6 +632,7 @@ init_r_port(int board, int aiop, int chan, struct pci_dev *pci_dev)
		tty_port_init(&info->port);
		info->port.ops = &rocket_port_ops;
		info->flags &= ~ROCKET_MODE_MASK;
		if (board < ARRAY_SIZE(pc104) && line < ARRAY_SIZE(pc104_1))
		switch (pc104[board][line]) {
		case 422:
		info->flags \|= ROCKET_MODE_RS422;
		@@ -644,6 +645,8 @@ init_r_port(int board, int aiop, int chan, struct pci_dev *pci_dev)
		info->flags \|= ROCKET_MODE_RS232;
		break;
		}
		else
		info->flags \|= ROCKET_MODE_RS232;

		info->intmask = RXF_TRIG \| TXFIFO_MT \| SRC_INT \| DELTA_CD \| DELTA_CTS \| DELTA_DSR;
		if (sInitChan(ctlp, &info->channel, aiop, chan) == 0) {

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