tty: vt_ioctl: fix potential Spectre v1
commit e97267cb4d
upstream.
vsa.console is indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/tty/vt/vt_ioctl.c:711 vt_ioctl() warn: potential spectre issue
'vc_cons' [r]
Fix this by sanitizing vsa.console before using it to index vc_cons
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
57c806be01
commit
4334a6ae86
|
@ -32,6 +32,8 @@
|
|||
#include <asm/io.h>
|
||||
#include <linux/uaccess.h>
|
||||
|
||||
#include <linux/nospec.h>
|
||||
|
||||
#include <linux/kbd_kern.h>
|
||||
#include <linux/vt_kern.h>
|
||||
#include <linux/kbd_diacr.h>
|
||||
|
@ -700,6 +702,8 @@ int vt_ioctl(struct tty_struct *tty,
|
|||
if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
|
||||
ret = -ENXIO;
|
||||
else {
|
||||
vsa.console = array_index_nospec(vsa.console,
|
||||
MAX_NR_CONSOLES + 1);
|
||||
vsa.console--;
|
||||
console_lock();
|
||||
ret = vc_allocate(vsa.console);
|
||||
|
|
Loading…
Reference in New Issue