From 80338b91d352d3a961d9cee44be29eae9f425804 Mon Sep 17 00:00:00 2001
From: Angie Chiang <angiebird@google.com>
Date: Tue, 20 Sep 2016 11:59:23 -0700
Subject: Detect invalid highbd iht input

Do nothing in vp9_highbd_iht#x#_##_add_c when input magnitude is beyond
20 bits. Note that, sign bit is not included here.

In the 20 bits, we use 12 bits for input signal, 7 bits for forward
transform amplification, and 1 bit for contingency in rounding and
quantizing

BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1286

Change-Id: I332c6f68df4614fc2e7d2dc4c5bb0d0cff8a245c
---
 vp9/common/vp9_idct.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/vp9/common/vp9_idct.c b/vp9/common/vp9_idct.c
index ff7c1dd3f..ec5cd33ce 100644
--- a/vp9/common/vp9_idct.c
+++ b/vp9/common/vp9_idct.c
@@ -204,6 +204,18 @@ void vp9_iht16x16_add(TX_TYPE tx_type, const tran_low_t *input, uint8_t *dest,
 }
 
 #if CONFIG_VP9_HIGHBITDEPTH
+
+// 12 signal input bits + 7 forward transform amplify bits + 1 bit
+// for contingency in rounding and quantizing
+#define VALID_IHT_MAGNITUDE_RANGE (1 << 20)
+
+static INLINE int detect_invalid_iht_input(const tran_low_t *input, int size) {
+  int i;
+  for (i = 0; i < size; ++i)
+    if (abs(input[i]) >= VALID_IHT_MAGNITUDE_RANGE) return 1;
+  return 0;
+}
+
 void vp9_highbd_iht4x4_16_add_c(const tran_low_t *input, uint8_t *dest8,
                                 int stride, int tx_type, int bd) {
   const highbd_transform_2d IHT_4[] = {
@@ -219,6 +231,13 @@ void vp9_highbd_iht4x4_16_add_c(const tran_low_t *input, uint8_t *dest8,
   tran_low_t *outptr = out;
   tran_low_t temp_in[4], temp_out[4];
 
+  if (detect_invalid_iht_input(input, 16)) {
+#if CONFIG_COEFFICIENT_RANGE_CHECKING
+    assert(0 && "invalid highbd iht input");
+#endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
+    return;
+  }
+
   // Inverse transform row vectors.
   for (i = 0; i < 4; ++i) {
     IHT_4[tx_type].rows(input, outptr, bd);
@@ -253,6 +272,13 @@ void vp9_highbd_iht8x8_64_add_c(const tran_low_t *input, uint8_t *dest8,
   const highbd_transform_2d ht = HIGH_IHT_8[tx_type];
   uint16_t *dest = CONVERT_TO_SHORTPTR(dest8);
 
+  if (detect_invalid_iht_input(input, 64)) {
+#if CONFIG_COEFFICIENT_RANGE_CHECKING
+    assert(0 && "invalid highbd iht input");
+#endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
+    return;
+  }
+
   // Inverse transform row vectors.
   for (i = 0; i < 8; ++i) {
     ht.rows(input, outptr, bd);
@@ -287,6 +313,13 @@ void vp9_highbd_iht16x16_256_add_c(const tran_low_t *input, uint8_t *dest8,
   const highbd_transform_2d ht = HIGH_IHT_16[tx_type];
   uint16_t *dest = CONVERT_TO_SHORTPTR(dest8);
 
+  if (detect_invalid_iht_input(input, 256)) {
+#if CONFIG_COEFFICIENT_RANGE_CHECKING
+    assert(0 && "invalid highbd iht input");
+#endif  // CONFIG_COEFFICIENT_RANGE_CHECKING
+    return;
+  }
+
   // Rows
   for (i = 0; i < 16; ++i) {
     ht.rows(input, outptr, bd);
-- 
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