v1.1.1, fuzzing, bugfix

supersnappy.nim

@@ -178,7 +178,7 @@ func uncompress*(src: openArray[uint8], dst: var seq[uint8]) =
 
       inc(ip, (entry shr 11).int + 1)
 
-      if dstLen - op < len or op <= offset - 1: # Catches offset == 0
+      if dstLen - op < len or op.uint <= offset.uint - 1: # Catches offset == 0
         failUncompress()
 
       if len <= 16 and offset >= 8 and dstLen > op + 16:

supersnappy.nimble

@@ -1,5 +1,5 @@
 packageName   = "supersnappy"
-version       = "1.1.0"
+version       = "1.1.1"
 author        = "Ryan Oldenburg"
 description   = "Nim implementation of Google's Snappy compression."
 license       = "MIT"

tests/fuzz.nim

@@ -0,0 +1,22 @@
+import strformat, random, supersnappy
+
+randomize()
+
+const files = [
+  "alice29.txt", "asyoulik.txt", "fireworks.jpg", "geo.protodata",
+  "html", "html_x_4", "kppkn.gtb", "lcet10.txt", "paper-100k.pdf",
+  "plrabn12.txt", "urls.10K"
+]
+
+for i in 0 ..< 10_000:
+  let file = files[rand(files.len - 1)]
+  var compressed = readFile(&"tests/data/{file}.snappy")
+  let
+    pos = rand(compressed.len - 1)
+    value = rand(255).char
+  compressed[pos] = value
+  echo &"{i} {file} {pos} {value.uint8}"
+  try:
+    assert uncompress(compressed).len > 0
+  except SnappyError:
+    discard