diff --git a/library/asn1write.c b/library/asn1write.c
index e50c17c..b1c98f4 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -85,7 +85,7 @@
         return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
 
     (*p) -= len;
-    mpi_write_binary( X, *p, len );
+    MPI_CHK( mpi_write_binary( X, *p, len ) );
 
     // DER format assumes 2s complement for numbers, so the leftmost bit
     // should be 0 for positive numbers and 1 for negative numbers.
@@ -102,7 +102,10 @@
     ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
     ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
 
-    return( len );
+    ret = (int) len;
+
+cleanup:
+    return( ret );
 }
     
 int asn1_write_null( unsigned char **p, unsigned char *start )
diff --git a/library/dhm.c b/library/dhm.c
index 90e5b4b..b6f9b9d 100644
--- a/library/dhm.c
+++ b/library/dhm.c
@@ -75,8 +75,9 @@
     int ret = POLARSSL_ERR_DHM_BAD_INPUT_DATA;
 
     mpi_init( &L ); mpi_init( &U );
-    mpi_lset( &L, 2 );
-    mpi_sub_int( &U, P, 2 );
+
+    MPI_CHK( mpi_lset( &L, 2 ) );
+    MPI_CHK( mpi_sub_int( &U, P, 2 ) );
 
     if( mpi_cmp_mpi( param, &L ) >= 0 &&
         mpi_cmp_mpi( param, &U ) <= 0 )
@@ -84,8 +85,8 @@
         ret = 0;
     }
 
+cleanup:
     mpi_free( &L ); mpi_free( &U );
-
     return( ret );
 }
 
@@ -139,7 +140,7 @@
         mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
 
         while( mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
-            mpi_shift_r( &ctx->X, 1 );
+            MPI_CHK( mpi_shift_r( &ctx->X, 1 ) );
 
         if( count++ > 10 )
             return( POLARSSL_ERR_DHM_MAKE_PARAMS_FAILED );
@@ -225,7 +226,7 @@
         mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
 
         while( mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
-            mpi_shift_r( &ctx->X, 1 );
+            MPI_CHK( mpi_shift_r( &ctx->X, 1 ) );
 
         if( count++ > 10 )
             return( POLARSSL_ERR_DHM_MAKE_PUBLIC_FAILED );
diff --git a/library/rsa.c b/library/rsa.c
index f56dd6a..616f5d9 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1424,6 +1424,7 @@
  */
 int rsa_self_test( int verbose )
 {
+    int ret = 0;
     size_t len;
     rsa_context rsa;
     unsigned char rsa_plaintext[PT_LEN];
@@ -1436,14 +1437,14 @@
     rsa_init( &rsa, RSA_PKCS_V15, 0 );
 
     rsa.len = KEY_LEN;
-    mpi_read_string( &rsa.N , 16, RSA_N  );
-    mpi_read_string( &rsa.E , 16, RSA_E  );
-    mpi_read_string( &rsa.D , 16, RSA_D  );
-    mpi_read_string( &rsa.P , 16, RSA_P  );
-    mpi_read_string( &rsa.Q , 16, RSA_Q  );
-    mpi_read_string( &rsa.DP, 16, RSA_DP );
-    mpi_read_string( &rsa.DQ, 16, RSA_DQ );
-    mpi_read_string( &rsa.QP, 16, RSA_QP );
+    MPI_CHK( mpi_read_string( &rsa.N , 16, RSA_N  ) );
+    MPI_CHK( mpi_read_string( &rsa.E , 16, RSA_E  ) );
+    MPI_CHK( mpi_read_string( &rsa.D , 16, RSA_D  ) );
+    MPI_CHK( mpi_read_string( &rsa.P , 16, RSA_P  ) );
+    MPI_CHK( mpi_read_string( &rsa.Q , 16, RSA_Q  ) );
+    MPI_CHK( mpi_read_string( &rsa.DP, 16, RSA_DP ) );
+    MPI_CHK( mpi_read_string( &rsa.DQ, 16, RSA_DQ ) );
+    MPI_CHK( mpi_read_string( &rsa.QP, 16, RSA_QP ) );
 
     if( verbose != 0 )
         printf( "  RSA key validation: " );
@@ -1523,9 +1524,9 @@
         printf( "passed\n\n" );
 #endif /* POLARSSL_SHA1_C */
 
+cleanup:
     rsa_free( &rsa );
-
-    return( 0 );
+    return( ret );
 }
 
 #endif