target/arm: Fix PAuth sbox functions

Fix CVE-2020-10702 bug

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>

target-arm-Fix-PAuth-sbox-functions.patch

@@ -0,0 +1,49 @@
+From a7149fc18020c3d432c31838069dcfcb745299bf Mon Sep 17 00:00:00 2001
+From: zhanghailiang <zhang.zhanghailiang@huawei.com>
+Date: Sat, 20 Jun 2020 12:01:30 +0800
+Subject: [PATCH] target/arm: Fix PAuth sbox functions
+
+In the PAC computation, sbox was applied over wrong bits.
+As this is a 4-bit sbox, bit index should be incremented by 4 instead of 16.
+
+Test vector from QARMA paper (https://eprint.iacr.org/2016/444.pdf) was
+used to verify one computation of the pauth_computepac() function which
+uses sbox2.
+
+Launchpad: https://bugs.launchpad.net/bugs/1859713
+Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
+Signed-off-by: Vincent DEHORS <vincent.dehors@smile.fr>
+Signed-off-by: Adrien GRASSEIN <adrien.grassein@smile.fr>
+Message-id: 20200116230809.19078-2-richard.henderson@linaro.org
+Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
+Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
+Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
+---
+ target/arm/pauth_helper.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
+index d3194f20..0a5f41e1 100644
+--- a/target/arm/pauth_helper.c
++++ b/target/arm/pauth_helper.c
+@@ -89,7 +89,7 @@ static uint64_t pac_sub(uint64_t i)
+     uint64_t o = 0;
+     int b;
+ 
+-    for (b = 0; b < 64; b += 16) {
++    for (b = 0; b < 64; b += 4) {
+         o |= (uint64_t)sub[(i >> b) & 0xf] << b;
+     }
+     return o;
+@@ -104,7 +104,7 @@ static uint64_t pac_inv_sub(uint64_t i)
+     uint64_t o = 0;
+     int b;
+ 
+-    for (b = 0; b < 64; b += 16) {
++    for (b = 0; b < 64; b += 4) {
+         o |= (uint64_t)inv_sub[(i >> b) & 0xf] << b;
+     }
+     return o;
+-- 
+2.23.0
+