Add buffer wrap checks and disable throwing of std::bad_alloc.

Android is built with exceptions disabled, but "operator new" and
"operator new[]" still throw std::bad_alloc on failure rather than
returning new.  In general this is a good thing, because it will cause
an immediate crash of the process rather than assigning a null pointer
which is probably not checked.  But most memory allocations in Keymaster
are checked, because it's written to run in an environment where new
does *not* throw.  This CL updates the code to explicitly use the
non-throwing new.

A handful of throwing news remain, but only in places where a crash on
failure is appropriate.

In addition, this CL also inserts buffer wrap checks in key locations
and changes the development-machine Makefile to build in 32-bit mode, to
make memory problems more apparent.

Bug: 21888473
Change-Id: I8ebc5ec12053e4f5274f6f57ce312abc10611cef

1 files changed, 2 insertions, 1 deletions

diff --git a/ecdsa_operation.cpp b/ecdsa_operation.cpp
index dcbf73f..89bcfa1 100644
--- a/ecdsa_operation.cpp
+++ b/ecdsa_operation.cpp
@@ -156,7 +156,8 @@ keymaster_error_t EcdsaSignOperation::Finish(const AuthorizationSet& /* addition
         if (EVP_DigestSignFinal(&digest_ctx_, output->peek_write(), &siglen) <= 0)
             return TranslateLastOpenSslError();
     }
-    output->advance_write(siglen);
+    if (!output->advance_write(siglen))
+        return KM_ERROR_UNKNOWN_ERROR;
     return KM_ERROR_OK;
 }