diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index 0448440a7..fc86337b4 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -168,7 +168,11 @@ int main( int argc, char *argv[] )
         fprintf( stderr, "Cipher '%s' not found\n", argv[4] );
         goto exit;
     }
-    cipher_init_ctx( &cipher_ctx, cipher_info);
+    if( ( ret = cipher_init_ctx( &cipher_ctx, cipher_info) ) != 0 )
+    {
+        fprintf( stderr, "cipher_init_ctx failed\n" );
+        goto exit;
+    }
 
     md_info = md_info_from_string( argv[5] );
     if( md_info == NULL )
@@ -325,11 +329,16 @@ int main( int argc, char *argv[] )
 
             if( fread( buffer, 1, ilen, fin ) != ilen )
             {
-                fprintf( stderr, "fread(%ld bytes) failed\n", (long) n );
+                fprintf( stderr, "fread(%ld bytes) failed\n", (long) ilen );
+                goto exit;
+            }
+
+            if( cipher_update( &cipher_ctx, buffer, ilen, output, &olen ) != 0 )
+            {
+                fprintf( stderr, "cipher_update() returned error\n");
                 goto exit;
             }
 
-            cipher_update( &cipher_ctx, buffer, ilen, output, &olen );
             md_hmac_update( &md_ctx, output, olen );
 
             if( fwrite( output, 1, olen, fout ) != olen )
@@ -423,9 +432,18 @@ int main( int argc, char *argv[] )
 
         memset( key, 0, sizeof( key ) );
 
-        cipher_setkey( &cipher_ctx, digest, cipher_info->key_length,
-            POLARSSL_DECRYPT );
-        cipher_reset( &cipher_ctx, IV);
+        if( cipher_setkey( &cipher_ctx, digest, cipher_info->key_length,
+                           POLARSSL_DECRYPT ) != 0 )
+        {
+            fprintf( stderr, "cipher_setkey() returned error\n" );
+            goto exit;
+        }
+
+        if( cipher_reset( &cipher_ctx, IV ) != 0 )
+        {
+            fprintf( stderr, "cipher_reset() returned error\n" );
+            goto exit;
+        }
 
         md_hmac_starts( &md_ctx, digest, 32 );
 
@@ -443,8 +461,13 @@ int main( int argc, char *argv[] )
             }
 
             md_hmac_update( &md_ctx, buffer, cipher_get_block_size( &cipher_ctx ) );
-            cipher_update( &cipher_ctx, buffer, cipher_get_block_size( &cipher_ctx ),
-                output, &olen );
+            if( cipher_update( &cipher_ctx, buffer,
+                               cipher_get_block_size( &cipher_ctx ),
+                               output, &olen ) != 0 )
+            {
+                fprintf( stderr, "cipher_update() returned error\n" );
+                goto exit;
+            }
 
             if( fwrite( output, 1, olen, fout ) != olen )
             {
diff --git a/programs/pkey/dh_genprime.c b/programs/pkey/dh_genprime.c
index 5732f507e..b11199181 100644
--- a/programs/pkey/dh_genprime.c
+++ b/programs/pkey/dh_genprime.c
@@ -69,7 +69,12 @@ int main( int argc, char *argv[] )
     ((void) argv);
 
     mpi_init( &G ); mpi_init( &P ); mpi_init( &Q );
-    mpi_read_string( &G, 10, GENERATOR );
+
+    if( ( ret = mpi_read_string( &G, 10, GENERATOR ) ) != 0 )
+    {
+        printf( " failed\n  ! mpi_read_string returned %d\n", ret );
+        goto exit;
+    }
 
     printf( "\nWARNING: You should not generate and use your own DHM primes\n" );
     printf( "         unless you are very certain of what you are doing!\n" );
diff --git a/programs/test/ssl_test.c b/programs/test/ssl_test.c
index c090a853f..04adf297e 100644
--- a/programs/test/ssl_test.c
+++ b/programs/test/ssl_test.c
@@ -278,7 +278,13 @@ static int ssl_test( struct options *opt )
     else  ssl_set_ciphersuites( &ssl, opt->force_ciphersuite );
 
     if( opt->iomode == IOMODE_NONBLOCK )
-        net_set_nonblock( client_fd );
+    {
+        if( ( ret = net_set_nonblock( client_fd ) ) != 0 )
+        {
+            printf( "  ! net_set_nonblock returned %d\n\n", ret );
+            return( ret );
+        }
+    }
 
      read_buf = (unsigned char *) malloc( opt->buffer_size );
     write_buf = (unsigned char *) malloc( opt->buffer_size );