Commit 2b3174c9 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Greg Kroah-Hartman
Browse files

n_gsm: Use array_index_nospec() with index that comes from userspace 

dc.channel used for indexing comes directly from copy_from_user(). Use
array_index_nospec() to mitigate speculative side-channel.

Link: https://lore.kernel.org/linux-serial/64306d13.ONswMlyWlVKLGkKR%25lkp@intel.com/


Cc: stable <stable@kernel.org>
Fixes: afe3154b ("tty: n_gsm: add ioctl for DLC config via ldisc handle")
Reported-by: default avatarkernel test robot <lkp@intel.com>
Reviewed-by: default avatarDaniel Starke <daniel.starke@siemens.com>
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230411164532.64175-1-ilpo.jarvinen@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f91cf1a3

drivers/tty/n_gsm.c

+8 −5
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <linux/ctype.h>

#include <linux/mm.h>

#include <linux/math.h>

#include <linux/nospec.h>

#include <linux/string.h>

#include <linux/slab.h>

#include <linux/poll.h>
@@ -3717,8 +3718,8 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 
	struct gsm_config_ext ce;

	struct gsm_dlci_config dc;

	struct gsm_mux *gsm = tty->disc_data;

	unsigned int base, addr;

	struct gsm_dlci *dlci;

	unsigned int base;



	switch (cmd) {

	case GSMIOC_GETCONF:
@@ -3747,9 +3748,10 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 
			return -EFAULT;

		if (dc.channel == 0 || dc.channel >= NUM_DLCI)

			return -EINVAL;

		dlci = gsm->dlci[dc.channel];

		addr = array_index_nospec(dc.channel, NUM_DLCI);

		dlci = gsm->dlci[addr];

		if (!dlci) {

			dlci = gsm_dlci_alloc(gsm, dc.channel);

			dlci = gsm_dlci_alloc(gsm, addr);

			if (!dlci)

				return -ENOMEM;

		}
@@ -3762,9 +3764,10 @@ static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 
			return -EFAULT;

		if (dc.channel == 0 || dc.channel >= NUM_DLCI)

			return -EINVAL;

		dlci = gsm->dlci[dc.channel];

		addr = array_index_nospec(dc.channel, NUM_DLCI);

		dlci = gsm->dlci[addr];

		if (!dlci) {

			dlci = gsm_dlci_alloc(gsm, dc.channel);

			dlci = gsm_dlci_alloc(gsm, addr);

			if (!dlci)

				return -ENOMEM;

		}