Commit 9a492f8c authored Jul 27, 2018 by Jeremy Cline Committed by Greg Kroah-Hartman Aug 06, 2018

net: socket: fix potential spectre v1 gadget in socketcall



commit c8e8cd579bb4265651df8223730105341e61a2d1 upstream.

'call' is a user-controlled value, so sanitize the array index after the
bounds check to avoid speculating past the bounds of the 'nargs' array.

Found with the help of Smatch:

net/socket.c:2508 __do_sys_socketcall() warn: potential spectre issue
'nargs' [r] (local cap)

Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Cline <jcline@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 18d97180

net/socket.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -89,6 +89,7 @@
		#include <linux/magic.h>
		#include <linux/slab.h>
		#include <linux/xattr.h>
		#include <linux/nospec.h>

		#include <asm/uaccess.h>
		#include <asm/unistd.h>
		@@ -2338,6 +2339,7 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args)

		if (call < 1 \|\| call > SYS_SENDMMSG)
		return -EINVAL;
		call = array_index_nospec(call, SYS_SENDMMSG + 1);

		len = nargs[call];
		if (len > sizeof(a))