Exhumed: Always perform a range check on a sequence's length.

Too many of these are not correct and prone to overflows so ignoring this is not good.
ZDoom · Nov 5, 2023 · c039882 · c039882
1 parent 40265e6
commit c039882
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/source/games/exhumed/src/sequence.cpp b/source/games/exhumed/src/sequence.cpp
@@ -450,7 +450,7 @@ void seq_PlotArrowSequence(const int nSprite, const FName seqFile, const int16_t
 //
 //---------------------------------------------------------------------------
 
-void seq_PlotSequence(const int nSprite, const FName seqFile, const int16_t seqIndex, const int16_t frameIndex, const int16_t nFlags)
+void seq_PlotSequence(const int nSprite, const FName seqFile, const int seqIndex, int frameIndex, const int nFlags)
 {
     tspritetype* pTSprite = mytspriteArray->get(nSprite);
     const auto pPlayer = getPlayer(nLocalPlayer);
@@ -464,7 +464,11 @@ void seq_PlotSequence(const int nSprite, const FName seqFile, const int16_t seqI
     }
 
     const auto fileSeqs = getFileSeqs(seqFile);
-    const auto& seqFrame = fileSeqs->Data(seqIndex + seqOffset)->frames[frameIndex];
+    if (seqIndex + seqOffset > fileSeqs->SSize()) return;
+    const auto& sequence = fileSeqs->Data(seqIndex + seqOffset);
+    if (sequence->frames.SSize() <= frameIndex) frameIndex = sequence->frames.SSize() - 1;
+
+    const auto& seqFrame = sequence->frames[frameIndex];
     const auto chunkCount = seqFrame.chunks.Size();
 
     const auto nShade = pTSprite->shade - (100 * !!(fileSeqs->Data(seqIndex)->frames[frameIndex].flags & 4));

diff --git a/source/games/exhumed/src/sequence.h b/source/games/exhumed/src/sequence.h
@@ -80,7 +80,7 @@ extern int16_t nPilotLightCount;
 
 void seq_LoadSequences();
 void seq_DrawGunSequence(const SeqFrame& seqFrame, double xPos, double yPos, int nShade, int nPal, DAngle nAngle, double nAlpha, int nStat = 0);
-void seq_PlotSequence(const int nSprite, const FName seqFile, const int16_t seqIndex, const int16_t frameIndex, const int16_t nFlags);
+void seq_PlotSequence(const int nSprite, const FName seqFile, const int seqIndex, int frameIndex, const int nFlags);
 void seq_PlotArrowSequence(const int nSprite, const FName seqFile, const int16_t seqIndex, const int frameIndex);
 void seq_DrawPilotLightSeq(double xPos, double yPos, double nAngle);