Add fuzz tests for `Decimal`/`UDecimal` parsing.

Signed-off-by: Jean Pierre Dudey <jeandudey@hotmail.com>

fuzz/Cargo.toml

@@ -14,7 +14,7 @@ honggfuzz_fuzz = ["honggfuzz"]
 [dependencies]
 honggfuzz = { version = "0.5", optional = true }
 afl = { version = "0.3", optional = true }
-bitcoin = { path = "..", features = ["fuzztarget"] }
+bitcoin = { path = "..", features = ["fuzztarget", "serde-decimal"] }
 
 # Prevent this from interfering with workspaces
 [workspace]
@@ -35,3 +35,11 @@ path = "fuzz_targets/deserialize_transaction.rs"
 [[bin]]
 name = "deserialize_address"
 path = "fuzz_targets/deserialize_address.rs"
+
+[[bin]]
+name = "deserialize_decimal"
+path = "fuzz_targets/deserialize_decimal.rs"
+
+[[bin]]
+name = "deserialize_udecimal"
+path = "fuzz_targets/deserialize_udecimal.rs"

fuzz/fuzz_targets/deserialize_decimal.rs

@@ -0,0 +1,61 @@
+extern crate bitcoin;
+use std::str::FromStr;
+fn do_test(data: &[u8]) {
+    let data_str = String::from_utf8_lossy(data);
+    let dec = match bitcoin::util::decimal::Decimal::from_str(&data_str) {
+        Ok(dec) => dec,
+        Err(_) => return,
+    };
+    let dec_roundtrip = match bitcoin::util::decimal::Decimal::from_str(&dec.to_string()) {
+        Ok(dec) => dec,
+        Err(_) => return,
+    };
+    assert_eq!(dec, dec_roundtrip);
+}
+
+#[cfg(feature = "afl")]
+extern crate afl;
+#[cfg(feature = "afl")]
+fn main() {
+    afl::read_stdio_bytes(|data| {
+        do_test(&data);
+    });
+}
+
+#[cfg(feature = "honggfuzz")]
+#[macro_use] extern crate honggfuzz;
+#[cfg(feature = "honggfuzz")]
+fn main() {
+    loop {
+        fuzz!(|data| {
+            do_test(data);
+        });
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    fn extend_vec_from_hex(hex: &str, out: &mut Vec<u8>) {
+        let mut b = 0;
+        for (idx, c) in hex.as_bytes().iter().enumerate() {
+            b <<= 4;
+            match *c {
+                b'A'...b'F' => b |= c - b'A' + 10,
+                b'a'...b'f' => b |= c - b'a' + 10,
+                b'0'...b'9' => b |= c - b'0',
+                _ => panic!("Bad hex"),
+            }
+            if (idx & 1) == 1 {
+                out.push(b);
+                b = 0;
+            }
+        }
+    }
+
+    #[test]
+    fn duplicate_crash() {
+        let mut a = Vec::new();
+        extend_vec_from_hex("00000000", &mut a);
+        super::do_test(&a);
+    }
+}

fuzz/fuzz_targets/deserialize_udecimal.rs

@@ -0,0 +1,61 @@
+extern crate bitcoin;
+use std::str::FromStr;
+fn do_test(data: &[u8]) {
+    let data_str = String::from_utf8_lossy(data);
+    let dec = match bitcoin::util::decimal::UDecimal::from_str(&data_str) {
+        Ok(dec) => dec,
+        Err(_) => return,
+    };
+    let dec_roundtrip = match bitcoin::util::decimal::UDecimal::from_str(&dec.to_string()) {
+        Ok(dec) => dec,
+        Err(_) => return,
+    };
+    assert_eq!(dec, dec_roundtrip);
+}
+
+#[cfg(feature = "afl")]
+extern crate afl;
+#[cfg(feature = "afl")]
+fn main() {
+    afl::read_stdio_bytes(|data| {
+        do_test(&data);
+    });
+}
+
+#[cfg(feature = "honggfuzz")]
+#[macro_use] extern crate honggfuzz;
+#[cfg(feature = "honggfuzz")]
+fn main() {
+    loop {
+        fuzz!(|data| {
+            do_test(data);
+        });
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    fn extend_vec_from_hex(hex: &str, out: &mut Vec<u8>) {
+        let mut b = 0;
+        for (idx, c) in hex.as_bytes().iter().enumerate() {
+            b <<= 4;
+            match *c {
+                b'A'...b'F' => b |= c - b'A' + 10,
+                b'a'...b'f' => b |= c - b'a' + 10,
+                b'0'...b'9' => b |= c - b'0',
+                _ => panic!("Bad hex"),
+            }
+            if (idx & 1) == 1 {
+                out.push(b);
+                b = 0;
+            }
+        }
+    }
+
+    #[test]
+    fn duplicate_crash() {
+        let mut a = Vec::new();
+        extend_vec_from_hex("00000000", &mut a);
+        super::do_test(&a);
+    }
+}