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, 4 insertions, 4 deletions

diff --git a/rsa_operation.h b/rsa_operation.h
index 4005dbd..a1de04c 100644
--- a/rsa_operation.h
+++ b/rsa_operation.h
@@ -209,7 +209,7 @@ class RsaSigningOperationFactory : public RsaDigestingOperationFactory {
     keymaster_purpose_t purpose() const override { return KM_PURPOSE_SIGN; }
     Operation* InstantiateOperation(keymaster_digest_t digest, keymaster_padding_t padding,
                                     EVP_PKEY* key) override {
-        return new RsaSignOperation(digest, padding, key);
+        return new (std::nothrow) RsaSignOperation(digest, padding, key);
     }
 };
 
@@ -220,7 +220,7 @@ class RsaVerificationOperationFactory : public RsaDigestingOperationFactory {
     keymaster_purpose_t purpose() const override { return KM_PURPOSE_VERIFY; }
     Operation* InstantiateOperation(keymaster_digest_t digest, keymaster_padding_t padding,
                                     EVP_PKEY* key) override {
-        return new RsaVerifyOperation(digest, padding, key);
+        return new (std::nothrow) RsaVerifyOperation(digest, padding, key);
     }
 };
 
@@ -230,7 +230,7 @@ class RsaVerificationOperationFactory : public RsaDigestingOperationFactory {
 class RsaEncryptionOperationFactory : public RsaCryptingOperationFactory {
     keymaster_purpose_t purpose() const override { return KM_PURPOSE_ENCRYPT; }
     Operation* InstantiateOperation(keymaster_padding_t padding, EVP_PKEY* key) override {
-        return new RsaEncryptOperation(padding, key);
+        return new (std::nothrow) RsaEncryptOperation(padding, key);
     }
 };
 
@@ -240,7 +240,7 @@ class RsaEncryptionOperationFactory : public RsaCryptingOperationFactory {
 class RsaDecryptionOperationFactory : public RsaCryptingOperationFactory {
     keymaster_purpose_t purpose() const override { return KM_PURPOSE_DECRYPT; }
     Operation* InstantiateOperation(keymaster_padding_t padding, EVP_PKEY* key) override {
-        return new RsaDecryptOperation(padding, key);
+        return new (std::nothrow) RsaDecryptOperation(padding, key);
     }
 };