jxl-coding: IntegerConfig validation (#30)

* jxl-coding: IntegerConfig validation * Update lib.rs
tirr-c · May 27, 2023 · 186fffb · 186fffb
1 parent 4a723b3
commit 186fffb
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/crates/jxl-coding/src/error.rs b/crates/jxl-coding/src/error.rs
@@ -3,10 +3,11 @@
 pub enum Error {
     Bitstream(jxl_bitstream::Error),
     Lz77NotAllowed,
-    InvalidPrefixHistogram,
     InvalidAnsHistogram,
     InvalidAnsStream,
+    InvalidIntegerConfig,
     InvalidPermutation,
+    InvalidPrefixHistogram,
 }
 
 impl std::error::Error for Error {
@@ -23,10 +24,11 @@ impl std::fmt::Display for Error {
         match self {
             Self::Bitstream(err) => write!(f, "error from bitstream: {}", err),
             Self::Lz77NotAllowed => write!(f, "LZ77-enabled decoder when it is not allowed"),
-            Self::InvalidPrefixHistogram => write!(f, "invalid Brotli prefix code"),
             Self::InvalidAnsHistogram => write!(f, "invalid ANS distribution"),
             Self::InvalidAnsStream => write!(f, "ANS stream verification failed"),
+            Self::InvalidIntegerConfig => write!(f, "invalid hybrid integer configuration"),
             Self::InvalidPermutation => write!(f, "invalid permutation"),
+            Self::InvalidPrefixHistogram => write!(f, "invalid Brotli prefix code"),
         }
     }
 }

diff --git a/crates/jxl-coding/src/lib.rs b/crates/jxl-coding/src/lib.rs
@@ -209,12 +209,18 @@ impl IntegerConfig {
         let (msb_in_token, lsb_in_token) = if split_exponent != log_alphabet_size {
             let msb_bits = add_log2_ceil(split_exponent);
             let msb_in_token = bitstream.read_bits(msb_bits)?;
+            if msb_in_token > split_exponent {
+                return Err(Error::InvalidIntegerConfig);
+            }
             let lsb_bits = add_log2_ceil(split_exponent - msb_in_token);
             let lsb_in_token = bitstream.read_bits(lsb_bits)?;
             (msb_in_token, lsb_in_token)
         } else {
             (0u32, 0u32)
         };
+        if lsb_in_token + msb_in_token > split_exponent {
+            return Err(Error::InvalidIntegerConfig)
+        }
         Ok(Self {
             split_exponent,
             split: 1 << split_exponent,