BIO_new_mem_buf should take const void *

BIO_FLAGS_MEM_RDONLY keeps the invariant.

(Imported from upstream's a38a159bfcbc94214dda00e0e6b1fc6454a23b78)

Change-Id: I4cb35615d76b77929915e370dbb7fec1455da069
Reviewed-on: https://boringssl-review.googlesource.com/7214
Reviewed-by: David Benjamin <davidben@google.com>

crypto/bio/bio_mem.c

@@ -64,7 +64,7 @@
 #include <openssl/mem.h>
 
 
-BIO *BIO_new_mem_buf(void *buf, int len) {
+BIO *BIO_new_mem_buf(const void *buf, int len) {
   BIO *ret;
   BUF_MEM *b;
   const size_t size = len < 0 ? strlen((char *)buf) : (size_t)len;
@@ -80,7 +80,8 @@ BIO *BIO_new_mem_buf(void *buf, int len) {
   }
 
   b = (BUF_MEM *)ret->ptr;
-  b->data = buf;
+  /* BIO_FLAGS_MEM_RDONLY ensures |b->data| is not written to. */
+  b->data = (void *)buf;
   b->length = size;
   b->max = size;
 

crypto/bio/bio_test.cc

@@ -331,7 +331,7 @@ static bool TestPrintf() {
 
 static bool ReadASN1(bool should_succeed, const uint8_t *data, size_t data_len,
                      size_t expected_len, size_t max_len) {
-  ScopedBIO bio(BIO_new_mem_buf(const_cast<uint8_t*>(data), data_len));
+  ScopedBIO bio(BIO_new_mem_buf(data, data_len));
 
   uint8_t *out;
   size_t out_len;

crypto/pkcs8/pkcs12_test.cc

@@ -708,7 +708,7 @@ static bool Test(const char *name, const uint8_t *der, size_t der_len) {
 }
 
 static bool TestCompat(const uint8_t *der, size_t der_len) {
-  ScopedBIO bio(BIO_new_mem_buf((void*) der, der_len));
+  ScopedBIO bio(BIO_new_mem_buf(der, der_len));
   if (!bio) {
     return false;
   }

crypto/x509/pkcs7_test.c

@@ -596,7 +596,7 @@ static int test_crl_reparse(const uint8_t *der_bytes, size_t der_len) {
 }
 
 static int test_pem_certs(const char *pem) {
-  BIO *bio = BIO_new_mem_buf((char *) pem, strlen(pem));
+  BIO *bio = BIO_new_mem_buf(pem, strlen(pem));
   STACK_OF(X509) *certs = sk_X509_new_null();
 
   if (!PKCS7_get_PEM_certificates(certs, bio)) {
@@ -618,7 +618,7 @@ static int test_pem_certs(const char *pem) {
 }
 
 static int test_pem_crls(const char *pem) {
-  BIO *bio = BIO_new_mem_buf((char *) pem, strlen(pem));
+  BIO *bio = BIO_new_mem_buf(pem, strlen(pem));
   STACK_OF(X509_CRL) *crls = sk_X509_CRL_new_null();
 
   if (!PKCS7_get_PEM_CRLs(crls, bio)) {
@@ -653,4 +653,3 @@ int main(void) {
   printf("PASS\n");
   return 0;
 }
-

crypto/x509/x509_test.cc

@@ -163,7 +163,7 @@ static const char kForgeryPEM[] =
 // CertFromPEM parses the given, NUL-terminated PEM block and returns an
 // |X509*|.
 static X509* CertFromPEM(const char *pem) {
-  ScopedBIO bio(BIO_new_mem_buf(const_cast<char*>(pem), strlen(pem)));
+  ScopedBIO bio(BIO_new_mem_buf(pem, strlen(pem)));
   return PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr);
 }
 

include/openssl/bio.h

@@ -368,12 +368,12 @@ OPENSSL_EXPORT int BIO_read_asn1(BIO *bio, uint8_t **out, size_t *out_len,
 /* BIO_s_mem returns a |BIO_METHOD| that uses a in-memory buffer. */
 OPENSSL_EXPORT const BIO_METHOD *BIO_s_mem(void);
 
-/* BIO_new_mem_buf creates BIO that reads and writes from |len| bytes at |buf|.
+/* BIO_new_mem_buf creates read-only BIO that reads from |len| bytes at |buf|.
  * It does not take ownership of |buf|. It returns the BIO or NULL on error.
  *
  * If |len| is negative, then |buf| is treated as a NUL-terminated string, but
  * don't depend on this in new code. */
-OPENSSL_EXPORT BIO *BIO_new_mem_buf(void *buf, int len);
+OPENSSL_EXPORT BIO *BIO_new_mem_buf(const void *buf, int len);
 
 /* BIO_mem_contents sets |*out_contents| to point to the current contents of
  * |bio| and |*out_len| to contain the length of that data. It returns one on

ssl/ssl_test.cc

@@ -1001,8 +1001,7 @@ static ScopedX509 GetTestCertificate() {
       "T5oQpHL9z/cCDLAKCKRa4uV0fhEdOWBqyR9p8y5jJtye72t6CuFUV5iqcpF4BH4f\n"
       "j2VNHwsSrJwkD4QUGlUtH7vwnQmyCFxZMmWAJg==\n"
       "-----END CERTIFICATE-----\n";
-  ScopedBIO bio(
-      BIO_new_mem_buf(const_cast<char *>(kCertPEM), strlen(kCertPEM)));
+  ScopedBIO bio(BIO_new_mem_buf(kCertPEM, strlen(kCertPEM)));
   return ScopedX509(PEM_read_bio_X509(bio.get(), nullptr, nullptr, nullptr));
 }
 
@@ -1023,7 +1022,7 @@ static ScopedEVP_PKEY GetTestKey() {
       "tfDwbqkta4xcux67//khAkEAvvRXLHTaa6VFzTaiiO8SaFsHV3lQyXOtMrBpB5jd\n"
       "moZWgjHvB2W9Ckn7sDqsPB+U2tyX0joDdQEyuiMECDY8oQ==\n"
       "-----END RSA PRIVATE KEY-----\n";
-  ScopedBIO bio(BIO_new_mem_buf(const_cast<char *>(kKeyPEM), strlen(kKeyPEM)));
+  ScopedBIO bio(BIO_new_mem_buf(kKeyPEM, strlen(kKeyPEM)));
   return ScopedEVP_PKEY(
       PEM_read_bio_PrivateKey(bio.get(), nullptr, nullptr, nullptr));
 }