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>
diff --git a/net/socket.c b/net/socket.c
index bd3b339..35fa349b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -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 @@
if (call < 1 || call > SYS_SENDMMSG)
return -EINVAL;
+ call = array_index_nospec(call, SYS_SENDMMSG + 1);
len = nargs[call];
if (len > sizeof(a))