Fixed fuzzer issue with lut16Type A2B ICC profiles

There was no check for if a profile had gamma table with 0 elements.
Now it verifies that the table has 2-4096 entries as the ICC specs say.

BUG=667695

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5124

Change-Id: I36de202e398654ce8dd88e765455b4c4577724d2
Reviewed-on: https://skia-review.googlesource.com/5124
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Robert Aftias <raftias@google.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/core/SkColorSpace_ICC.cpp b/src/core/SkColorSpace_ICC.cpp
index 4e81c30471..5c5cfe0e9a 100644
--- a/src/core/SkColorSpace_ICC.cpp
+++ b/src/core/SkColorSpace_ICC.cpp
@@ -1079,6 +1079,27 @@ bool load_a2b0_lutn_type(std::vector<SkColorSpace_A2B::Element>* elements, const
         inTableEntries  = read_big_endian_u16(src + 48);
         outTableEntries = read_big_endian_u16(src + 50);
         precision       = 2;
+        
+        constexpr size_t kMaxLut16GammaEntries = 4096;
+        if (inTableEntries < 2) {
+            SkColorSpacePrintf("Too few (%d) input gamma table entries. Must have at least 2.\n",
+                               inTableEntries);
+            return false;
+        } else if (inTableEntries > kMaxLut16GammaEntries) {
+            SkColorSpacePrintf("Too many (%d) input gamma table entries. Must have at most %d.\n",
+                               inTableEntries, kMaxLut16GammaEntries);
+            return false;
+        }
+        
+        if (outTableEntries < 2) {
+            SkColorSpacePrintf("Too few (%d) output gamma table entries. Must have at least 2.\n",
+                               outTableEntries);
+            return false;
+        } else if (outTableEntries > kMaxLut16GammaEntries) {
+            SkColorSpacePrintf("Too many (%d) output gamma table entries. Must have at most %d.\n",
+                               outTableEntries, kMaxLut16GammaEntries);
+            return false;
+        }
     }
 
     const size_t inputOffset = dataOffset;