Check return value on write() to fix warning.

src/platform/vboot_reference/utils/dumpRSAPublicKey.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* C port of DumpPublicKey.java from the Android Open source project with
  * support for additional RSA key sizes. (platform/system/core,git/libmincrypt
  * /tools/DumpPublicKey.java). Uses the OpenSSL X509 and BIGNUM library.
  */
 
@@ skipping 35 matching lines @@
   BIGNUM *Big1, *Big2, *Big32, *BigMinus1;
   BIGNUM *B;
   BIGNUM *N0inv, *R, *RR, *RRTemp, *NnumBits;
   BIGNUM *n, *rr;
   BN_CTX *bn_ctx = BN_CTX_new();
   uint32_t n0invout;
 
   N = key->n;
   /* Output size of RSA key in 32-bit words */
   nwords = BN_num_bits(N) / 32;
-  write(1, &nwords, sizeof(nwords));
+  if (-1 == write(1, &nwords, sizeof(nwords)))
+    goto failure;
+
 
   /* Initialize BIGNUMs */
   Big1 = BN_new();
   Big2 = BN_new();
   Big32 = BN_new();
   BigMinus1 = BN_new();
   N0inv= BN_new();
   R = BN_new();
   RR = BN_new();
   RRTemp = BN_new();
   NnumBits = BN_new();
   n = BN_new();
   rr = BN_new();
 
 
   BN_set_word(Big1, 1L);
   BN_set_word(Big2, 2L);
   BN_set_word(Big32, 32L);
   BN_sub(BigMinus1, Big1, Big2);
 
   B = BN_new();
   BN_exp(B, Big2, Big32, bn_ctx); /* B = 2^32 */
 
   /* Calculate and output N0inv = -1 / N[0] mod 2^32 */
   BN_mod_inverse(N0inv, N, B, bn_ctx);
   BN_sub(N0inv, B, N0inv);
   n0invout = BN_get_word(N0inv);
-  write(1, &n0invout, sizeof(n0invout));
+  if (-1 == write(1, &n0invout, sizeof(n0invout)))
+    goto failure;
 
   /* Calculate R = 2^(# of key bits) */
   BN_set_word(NnumBits, BN_num_bits(N));
   BN_exp(R, Big2, NnumBits, bn_ctx);
 
   /* Calculate RR = R^2 mod N */
   BN_copy(RR, R);
   BN_mul(RRTemp, RR, R, bn_ctx);
   BN_mod(RR, RRTemp, N, bn_ctx);
 
 
   /* Write out modulus as little endian array of integers. */
   for (i = 0; i < nwords; ++i) {
     uint32_t nout;
 
     BN_mod(n, N, B, bn_ctx); /* n = N mod B */
     nout = BN_get_word(n);
-    write(1, &nout, sizeof(nout));
+    if (-1 == write(1, &nout, sizeof(nout)))
+      goto failure;
 
     BN_rshift(N, N, 32); /*  N = N/B */
   }
 
   /* Write R^2 as little endian array of integers. */
   for (i = 0; i < nwords; ++i) {
     uint32_t rrout;
 
     BN_mod(rr, RR, B, bn_ctx); /* rr = RR mod B */
     rrout = BN_get_word(rr);
-    write(1, &rrout, sizeof(rrout));
+    if (-1 == write(1, &rrout, sizeof(rrout)))
+      goto failure;
 
     BN_rshift(RR, RR, 32); /* RR = RR/B */
   }
 
+failure:
   /* Free BIGNUMs. */
   BN_free(Big1);
   BN_free(Big2);
   BN_free(Big32);
   BN_free(BigMinus1);
   BN_free(N0inv);
   BN_free(R);
   BN_free(RRTemp);
   BN_free(NnumBits);
   BN_free(n);
@@ skipping 38 matching lines @@
     output (pubkey);
   }
 
 fail:
   X509_free(cert);
   RSA_free(pubkey);
   fclose(fp);
 
   return 0;
 }