diff --git a/ChangeLog b/ChangeLog index ecd4769eb..86beaf70c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,6 +1,9 @@ PolarSSL ChangeLog -= Version 1.2.10 released 2013-10-04 += Version 1.2.10 released 2013-10-07 +Changes + * Changed RSA blinding to a slower but thread-safe version + Bugfix * Fixed memory leak in RSA as a result of introduction of blinding * Fixed ssl_pkcs11_decrypt() prototype diff --git a/include/polarssl/rsa.h b/include/polarssl/rsa.h index 64e7f6c26..1159b9421 100644 --- a/include/polarssl/rsa.h +++ b/include/polarssl/rsa.h @@ -151,11 +151,6 @@ typedef struct mpi RP; /*!< cached R^2 mod P */ mpi RQ; /*!< cached R^2 mod Q */ -#if !defined(POLARSSL_RSA_NO_CRT) - mpi Vi; /*!< cached blinding value */ - mpi Vf; /*!< cached un-blinding value */ -#endif - int padding; /*!< RSA_PKCS_V15 for 1.5 padding and RSA_PKCS_v21 for OAEP/PSS */ int hash_id; /*!< Hash identifier of md_type_t as diff --git a/library/rsa.c b/library/rsa.c index 65211a3fe..953e85258 100644 --- a/library/rsa.c +++ b/library/rsa.c @@ -252,46 +252,6 @@ cleanup: return( 0 ); } -#if !defined(POLARSSL_RSA_NO_CRT) -/* - * Generate or update blinding values, see section 10 of: - * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, - * DSS, and other systems. In : Advances in Cryptology—CRYPTO’96. Springer - * Berlin Heidelberg, 1996. p. 104-113. - */ -static int rsa_prepare_blinding( rsa_context *ctx, - int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) -{ - int ret; - - if( ctx->Vf.p != NULL ) - { - /* We already have blinding values, just update them by squaring */ - MPI_CHK( mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) ); - MPI_CHK( mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) ); - MPI_CHK( mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) ); - MPI_CHK( mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) ); - - return( 0 ); - } - - /* Unblinding value: Vf = random number */ - MPI_CHK( mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) ); - - /* Mathematically speaking, the algorithm should check Vf - * against 0, P and Q (Vf should be relatively prime to N, and 0 < Vf < N), - * so that Vf^-1 exists. - */ - - /* Blinding value: Vi = Vf^(-e) mod N */ - MPI_CHK( mpi_inv_mod( &ctx->Vi, &ctx->Vf, &ctx->N ) ); - MPI_CHK( mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) ); - -cleanup: - return( ret ); -} -#endif - /* * Do an RSA private key operation */ @@ -303,9 +263,10 @@ int rsa_private( rsa_context *ctx, { int ret; size_t olen; - mpi T, T1, T2; + mpi T, T1, T2, Vi, Vf; mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 ); + mpi_init( &Vi ); mpi_init( &Vf ); MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); @@ -326,8 +287,19 @@ int rsa_private( rsa_context *ctx, * Blinding * T = T * Vi mod N */ - MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) ); - MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vi ) ); + /* Unblinding value: Vf = random number */ + MPI_CHK( mpi_fill_random( &Vf, ctx->len - 1, f_rng, p_rng ) ); + + /* Mathematically speaking, the algorithm should check Vf + * against 0, P and Q (Vf should be relatively prime to N, and 0 < Vf < N), + * so that Vf^-1 exists. + */ + + /* Blinding value: Vi = Vf^(-e) mod N */ + MPI_CHK( mpi_inv_mod( &Vi, &Vf, &ctx->N ) ); + MPI_CHK( mpi_exp_mod( &Vi, &Vi, &ctx->E, &ctx->N, &ctx->RN ) ); + + MPI_CHK( mpi_mul_mpi( &T, &T, &Vi ) ); MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) ); } @@ -359,7 +331,7 @@ int rsa_private( rsa_context *ctx, * Unblind * T = T * Vf mod N */ - MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vf ) ); + MPI_CHK( mpi_mul_mpi( &T, &T, &Vf ) ); MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) ); } #endif @@ -370,6 +342,7 @@ int rsa_private( rsa_context *ctx, cleanup: mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 ); + mpi_free( &Vi ); mpi_free( &Vf ); if( ret != 0 ) return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret ); @@ -1354,9 +1327,6 @@ int rsa_pkcs1_verify( rsa_context *ctx, */ void rsa_free( rsa_context *ctx ) { -#if !defined(POLARSSL_RSA_NO_CRT) - mpi_free( &ctx->Vi ); mpi_free( &ctx->Vf ); -#endif mpi_free( &ctx->RQ ); mpi_free( &ctx->RP ); mpi_free( &ctx->RN ); mpi_free( &ctx->QP ); mpi_free( &ctx->DQ ); mpi_free( &ctx->DP ); mpi_free( &ctx->Q ); mpi_free( &ctx->P ); mpi_free( &ctx->D );