Initialise return values to an error

Initialising the return values to and error is best practice and makes
the library more robust.
diff --git a/library/ecp.c b/library/ecp.c
index c281d84..1ad1697 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -81,6 +81,7 @@
 #include "mbedtls/ecp.h"
 #include "mbedtls/threading.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 
 #include <string.h>
 
@@ -634,7 +635,7 @@
  */
 int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( P != NULL );
     ECP_VALIDATE_RET( Q != NULL );
 
@@ -662,7 +663,7 @@
  */
 int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( pt != NULL );
 
     MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->X , 1 ) );
@@ -708,7 +709,7 @@
 int mbedtls_ecp_point_read_string( mbedtls_ecp_point *P, int radix,
                            const char *x, const char *y )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( P != NULL );
     ECP_VALIDATE_RET( x != NULL );
     ECP_VALIDATE_RET( y != NULL );
@@ -903,7 +904,7 @@
                          int format, size_t *olen,
                          unsigned char *buf, size_t blen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( grp  != NULL );
     ECP_VALIDATE_RET( pt   != NULL );
     ECP_VALIDATE_RET( olen != NULL );
@@ -936,7 +937,7 @@
 int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp,
                                 const unsigned char **buf, size_t len )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_group_id grp_id;
     ECP_VALIDATE_RET( grp  != NULL );
     ECP_VALIDATE_RET( buf  != NULL );
@@ -1031,7 +1032,7 @@
  */
 static int ecp_modp( mbedtls_mpi *N, const mbedtls_ecp_group *grp )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     if( grp->modp == NULL )
         return( mbedtls_mpi_mod_mpi( N, N, &grp->P ) );
@@ -1088,7 +1089,7 @@
                                        const mbedtls_mpi *A,
                                        const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( X, A, B ) );
     MOD_MUL( *X );
 cleanup:
@@ -1108,7 +1109,7 @@
                                        const mbedtls_mpi *A,
                                        const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( X, A, B ) );
     MOD_SUB( *X );
 cleanup:
@@ -1129,7 +1130,7 @@
                                        const mbedtls_mpi *A,
                                        const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( X, A, B ) );
     MOD_ADD( *X );
 cleanup:
@@ -1140,7 +1141,7 @@
                                            mbedtls_mpi *X,
                                            size_t count )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( X, count ) );
     MOD_ADD( *X );
 cleanup:
@@ -1162,7 +1163,7 @@
  */
 static int ecp_normalize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi Zi, ZZi;
 
     if( mbedtls_mpi_cmp_int( &pt->Z, 0 ) == 0 )
@@ -1214,7 +1215,7 @@
 static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp,
                                    mbedtls_ecp_point *T[], size_t T_size )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i;
     mbedtls_mpi *c, u, Zi, ZZi;
 
@@ -1303,7 +1304,7 @@
                             mbedtls_ecp_point *Q,
                             unsigned char inv )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char nonzero;
     mbedtls_mpi mQY;
 
@@ -1337,7 +1338,7 @@
 static int ecp_double_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
                            const mbedtls_ecp_point *P )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi M, S, T, U;
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -1433,7 +1434,7 @@
 static int ecp_add_mixed( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
                           const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi T1, T2, T3, T4, X, Y, Z;
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -1521,7 +1522,7 @@
 static int ecp_randomize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi l, ll;
     size_t p_size;
     int count = 0;
@@ -1693,7 +1694,7 @@
                                 unsigned char w, size_t d,
                                 mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char i;
     size_t j = 0;
     const unsigned char T_size = 1U << ( w - 1 );
@@ -1829,7 +1830,7 @@
                             const mbedtls_ecp_point T[], unsigned char T_size,
                             unsigned char i )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char ii, j;
 
     /* Ignore the "sign" bit and scale down */
@@ -1862,7 +1863,7 @@
                               void *p_rng,
                               mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_point Txi;
     size_t i;
 
@@ -1942,7 +1943,7 @@
                                    unsigned char w,
                                    unsigned char *parity_trick )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi M, mm;
 
     mbedtls_mpi_init( &M );
@@ -1988,7 +1989,7 @@
                                 void *p_rng,
                                 mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char parity_trick;
     unsigned char k[COMB_MAX_D + 1];
     mbedtls_ecp_point *RR = R;
@@ -2083,7 +2084,7 @@
                          void *p_rng,
                          mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char w, p_eq_g, i;
     size_t d;
     unsigned char T_size, T_ok;
@@ -2215,7 +2216,7 @@
  */
 static int ecp_normalize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
 #if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT)
     if( mbedtls_internal_ecp_grp_capable( grp ) )
@@ -2241,7 +2242,7 @@
 static int ecp_randomize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi l;
     size_t p_size;
     int count = 0;
@@ -2296,7 +2297,7 @@
                                const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q,
                                const mbedtls_mpi *d )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi A, AA, B, BB, E, C, D, DA, CB;
 
 #if defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT)
@@ -2344,7 +2345,7 @@
                         int (*f_rng)(void *, unsigned char *, size_t),
                         void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i;
     unsigned char b;
     mbedtls_ecp_point RP;
@@ -2484,7 +2485,7 @@
  */
 static int ecp_check_pubkey_sw( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi YY, RHS;
 
     /* pt coordinates must be normalized for our checks */
@@ -2537,7 +2538,7 @@
                                       const mbedtls_ecp_point *P,
                                       mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     if( mbedtls_mpi_cmp_int( m, 1 ) == 0 )
     {
@@ -2569,7 +2570,7 @@
              const mbedtls_mpi *n, const mbedtls_ecp_point *Q,
              mbedtls_ecp_restart_ctx *rs_ctx )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_point mP;
     mbedtls_ecp_point *pmP = &mP;
     mbedtls_ecp_point *pR = R;
@@ -2846,7 +2847,7 @@
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( grp   != NULL );
     ECP_VALIDATE_RET( d     != NULL );
     ECP_VALIDATE_RET( G     != NULL );
@@ -2882,7 +2883,7 @@
 int mbedtls_ecp_gen_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     ECP_VALIDATE_RET( key   != NULL );
     ECP_VALIDATE_RET( f_rng != NULL );
 
@@ -2966,7 +2967,7 @@
  */
 int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_point Q;
     mbedtls_ecp_group grp;
     ECP_VALIDATE_RET( pub != NULL );
@@ -3012,7 +3013,7 @@
  */
 int mbedtls_ecp_self_test( int verbose )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i;
     mbedtls_ecp_group grp;
     mbedtls_ecp_point R, P;