Merge pull request #36116 from missirol/develUBSAN_hitPattern

fix for out-of-bounds index in `HitPattern::getHitPatternByAbsoluteIndex`
cms-sw · Nov 18, 2021 · 215e2f7 · 215e2f7
2 parents c44be9a + 9e53f33
commit 215e2f7
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/DataFormats/TrackReco/src/HitPattern.cc b/DataFormats/TrackReco/src/HitPattern.cc
@@ -334,6 +334,8 @@ uint16_t HitPattern::getHitPatternByAbsoluteIndex(int position) const {
   } else {
     uint8_t firstWordBits = HIT_LENGTH - secondWordBits;
     uint16_t firstWordBlock = hitPattern[secondWord - 1] >> (16 - firstWordBits);
+    if (secondWordBits == 0)
+      return firstWordBlock;
     uint16_t secondWordBlock = hitPattern[secondWord] & ((1 << secondWordBits) - 1);
     uint16_t myResult = firstWordBlock + (secondWordBlock << firstWordBits);
     return myResult;