Merge pull request #4201 from rorosen/seek-table-create-null-check

prevent possible segfault when creating seek table

contrib/seekable_format/zstdseek_decompress.c

@@ -252,6 +252,8 @@ size_t ZSTD_seekable_free(ZSTD_seekable* zs)
 
 ZSTD_seekTable* ZSTD_seekTable_create_fromSeekable(const ZSTD_seekable* zs)
 {
+    assert(zs != NULL);
+    if (zs->seekTable.entries == NULL) return NULL;
     ZSTD_seekTable* const st = (ZSTD_seekTable*)malloc(sizeof(ZSTD_seekTable));
     if (st==NULL) return NULL;
 

lib/zstd.h

@@ -224,7 +224,7 @@ ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize)
  * it's recommended to provide @dstCapacity >= ZSTD_compressBound(srcSize)
  * as it eliminates one potential failure scenario,
  * aka not enough room in dst buffer to write the compressed frame.
- * Note : ZSTD_compressBound() itself can fail, if @srcSize > ZSTD_MAX_INPUT_SIZE .
+ * Note : ZSTD_compressBound() itself can fail, if @srcSize >= ZSTD_MAX_INPUT_SIZE .
  *        In which case, ZSTD_compressBound() will return an error code
  *        which can be tested using ZSTD_isError().
  *