commit 6b155dc1a6c7c7bd345514a31288c260e4588216 Author: teor teor2345@gmail.com Date: Sun Sep 28 20:34:21 2014 -0400

Stop signed left shifts overflowing in ed25519: Macros

The macros let us use unsigned types for potentially overflowing left shifts. Create SHL32() and SHL64() and SHL8() macros for convenience. --- src/ext/ed25519/ref10/crypto_int32.h | 22 ++++++++++++++++++++++ src/ext/ed25519/ref10/crypto_int64.h | 20 ++++++++++++++++++++ 2 files changed, 42 insertions(+)

diff --git a/src/ext/ed25519/ref10/crypto_int32.h b/src/ext/ed25519/ref10/crypto_int32.h index cd5c7c2..dd13c91 100644 --- a/src/ext/ed25519/ref10/crypto_int32.h +++ b/src/ext/ed25519/ref10/crypto_int32.h @@ -1,3 +1,25 @@ /* Added for Tor. */ + +#ifndef CRYPTO_INT32_H +#define CRYPTO_INT32_H + #include "torint.h" #define crypto_int32 int32_t +#define crypto_uint32 uint32_t + +/* + Stop signed left shifts overflowing + by using unsigned types for bitwise operations + */ + +#ifndef OVERFLOW_SAFE_SIGNED_LSHIFT +#define OVERFLOW_SAFE_SIGNED_LSHIFT(s, lshift, utype, stype) \ + ((stype)((utype)(s) << (utype)(lshift))) +#endif + +#define SHL32(s, lshift) \ + OVERFLOW_SAFE_SIGNED_LSHIFT(s, lshift, crypto_uint32, crypto_int32) +#define SHL8(s, lshift) \ + OVERFLOW_SAFE_SIGNED_LSHIFT(s, lshift, unsigned char, signed char) + +#endif /* CRYPTO_INT32_H */ diff --git a/src/ext/ed25519/ref10/crypto_int64.h b/src/ext/ed25519/ref10/crypto_int64.h index de0b602..46e8852 100644 --- a/src/ext/ed25519/ref10/crypto_int64.h +++ b/src/ext/ed25519/ref10/crypto_int64.h @@ -1,3 +1,23 @@ /* Added for Tor. */ + +#ifndef CRYPTO_INT64_H +#define CRYPTO_INT64_H + #include "torint.h" #define crypto_int64 int64_t +#define crypto_uint64 uint64_t + +/* + Stop signed left shifts overflowing + by using unsigned types for bitwise operations + */ + +#ifndef OVERFLOW_SAFE_SIGNED_LSHIFT +#define OVERFLOW_SAFE_SIGNED_LSHIFT(s, lshift, utype, stype) \ + ((stype)((utype)(s) << (utype)(lshift))) +#endif + +#define SHL64(s, lshift) \ + OVERFLOW_SAFE_SIGNED_LSHIFT(s, lshift, crypto_uint64, crypto_int64) + +#endif /* CRYPTO_INT64_H */