Commit dab8c7a5 authored by Theo Buehler's avatar Theo Buehler
Browse files

Enable BN_mod_sqrt() for upcoming LibreSSL 3.8.2 

This API was inherited from OpenSSL, so it has always been present.
Enable it for the upcoming LibreSSL release.

The test as it was written would fail since LibreSSL returns the other
square root. Improve the test to work with all possible implementations
with a more interesting test case. Also check for error in the simplest
situation where no square root exists.
parent 0917bed2

openssl-sys/src/handwritten/bn.rs

+1 −1
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ extern "C" { 
        m: *const BIGNUM,

        ctx: *mut BN_CTX,

    ) -> c_int;

    #[cfg(ossl110)]

    #[cfg(any(ossl110, libressl382))]

    pub fn BN_mod_sqrt(

        ret: *mut BIGNUM,

        a: *const BIGNUM,

openssl/src/bn.rs

+13 −6
Original line number Diff line number Diff line
@@ -655,7 +655,7 @@ impl BigNumRef { 


    /// Places into `self` the modular square root of `a` such that `self^2 = a (mod p)`

    #[corresponds(BN_mod_sqrt)]

    #[cfg(ossl110)]

    #[cfg(any(ossl110, libressl382))]

    pub fn mod_sqrt(

        &mut self,

        a: &BigNumRef,
@@ -1490,17 +1490,24 @@ mod tests { 
        assert!(b.is_const_time())

    }



    #[cfg(ossl110)]

    #[cfg(any(ossl110, libressl382))]

    #[test]

    fn test_mod_sqrt() {

        let mut ctx = BigNumContext::new().unwrap();



        let s = BigNum::from_hex_str("47A8DD7626B9908C80ACD7E0D3344D69").unwrap();

        let p = BigNum::from_hex_str("81EF47265B58BCE5").unwrap();

        let s = BigNum::from_hex_str("2").unwrap();

        let p = BigNum::from_hex_str("7DEB1").unwrap();

        let mut sqrt = BigNum::new().unwrap();

        let mut out = BigNum::new().unwrap();



        out.mod_sqrt(&s, &p, &mut ctx).unwrap();

        assert_eq!(out, BigNum::from_hex_str("7C6D179E19B97BDD").unwrap());

        // Square the root because OpenSSL randomly returns one of 2E42C or 4FA85

        sqrt.mod_sqrt(&s, &p, &mut ctx).unwrap();

        out.mod_sqr(&sqrt, &p, &mut ctx).unwrap();

        assert!(out == s);



        let s = BigNum::from_hex_str("3").unwrap();

        let p = BigNum::from_hex_str("5").unwrap();

        assert!(out.mod_sqrt(&s, &p, &mut ctx).is_err());

    }



    #[test]