Avoid oss fuzz checks in c++ by initializing scans differently

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>
kdt3rd · May 5, 2024 · ae646ec · ae646ec
1 parent c6b7e96
commit ae646ec
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Showing 6 changed files with 22 additions and 4 deletions.
diff --git a/src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp b/src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp
@@ -537,6 +537,12 @@ readSampleCountForLineBlock (
     int                          sampleCountMinY,
     bool                         writeToSlice)
 {
+    if (lineBlockId < 0 || lineBlockId >= (int) data->lineOffsets.size ())
+    {
+        THROW (IEX_NAMESPACE::ArgExc,
+               "Invalid line block id: " << lineBlockId);
+    }
+
     streamData->is->seekg (data->lineOffsets[lineBlockId]);
 
     if (isMultiPart (data->version))

diff --git a/src/lib/OpenEXR/ImfScanLineInputFile.cpp b/src/lib/OpenEXR/ImfScanLineInputFile.cpp
@@ -437,7 +437,9 @@ void ScanLineInputFile::Data::readPixels (
             << dw.min.y << " - " << dw.max.y);
     }
 
-    nchunks = 1 + (((int64_t) scanLine2 - (int64_t) scanLine1) / (int64_t) scansperchunk);
+    nchunks = ((int64_t) scanLine2 - (int64_t) scanLine1);
+    nchunks /= (int64_t) scansperchunk;
+    nchunks += 1;
 
     exr_chunk_info_t      cinfo;
 #if ILMTHREAD_THREADING_ENABLED

diff --git a/src/lib/OpenEXRCore/chunk.c b/src/lib/OpenEXRCore/chunk.c
@@ -756,9 +756,11 @@ exr_chunk_default_initialize (
     if (box->min.y < dw.min.y || box->min.y > dw.max.y)
         return EXR_ERR_INVALID_ARGUMENT;
 
-    if (ctxt->mode == EXR_CONTEXT_TEMPORARY)
+    if (ctxt->mode == EXR_CONTEXT_TEMPORARY && part->chunk_count < 0)
     {
         part->chunk_count = internal_exr_compute_chunk_offset_size (part);
+        if (part->chunk_count < 0)
+            return EXR_ERR_INVALID_ARGUMENT;
     }
 
     if (part->storage_mode == EXR_STORAGE_SCANLINE ||

diff --git a/src/lib/OpenEXRCore/context.c b/src/lib/OpenEXRCore/context.c
@@ -667,6 +667,12 @@ exr_write_header (exr_context_t ctxt)
         if (rv != EXR_ERR_SUCCESS) break;
 
         ccount = internal_exr_compute_chunk_offset_size (curp);
+        if (ccount < 0)
+            return EXR_UNLOCK_AND_RETURN (
+                ctxt->report_error (
+                    ctxt,
+                    EXR_ERR_FILE_BAD_HEADER,
+                    "Invalid part specification computing number of chunks in file"));
 
         curp->chunk_count = ccount;
 

diff --git a/src/lib/OpenEXRCore/internal_structs.c b/src/lib/OpenEXRCore/internal_structs.c
@@ -228,6 +228,7 @@ internal_exr_add_part (
     part->display_window.max.x = -1;
     part->display_window.max.y = -1;
     part->chunk_count          = -1;
+    part->lines_per_chunk      = -1;
 
     part->zip_compression_level = f->default_zip_level;
     part->dwa_compression_level = f->default_dwa_quality;

diff --git a/src/lib/OpenEXRCore/parse_header.c b/src/lib/OpenEXRCore/parse_header.c
@@ -2359,9 +2359,10 @@ internal_exr_compute_chunk_offset_size (exr_priv_part_t curpart)
         int linePerChunk, h;
 
         linePerChunk = exr_compression_lines_per_chunk (curpart->comp_type);
-        if (linePerChunk < 0) return -1;
 
-        curpart->lines_per_chunk         = ((int16_t) linePerChunk);
+        curpart->lines_per_chunk = linePerChunk;
+
+        if (linePerChunk < 0) return -1;
 
         for (int c = 0; c < channels->num_channels; ++c)
         {