commit 80338b91d352d3a961d9cee44be29eae9f425804
author Angie Chiang <angiebird@google.com> Tue Sep 20 11:59:23 2016 -0700
committer Angie Chiang <angiebird@google.com> Wed Sep 21 17:15:19 2016 -0700
tree 18599835f580ef2dc614636e201655be45317c72
parent 0695843a216dd63e8ac087e13c44de81e8a50afe

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

diff --git a/vp9/common/vp9_idct.c b/vp9/common/vp9_idct.c
index ff7c1dd..ec5cd33 100644
--- a/vp9/common/vp9_idct.c
+++ b/vp9/common/vp9_idct.c
@@ -204,6 +204,18 @@
 }
 
 #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 @@
   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 @@
   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 @@
   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);