[openssl-dev] [openssl.org #3995] [PATCH] Fix VS2008 "implicitly converted to 64 bits" build warning

[David Woodhouse via RT]

When building with Visual Studio 2008, I get the following warning:

C4334: '<<' : result of 32-bit shift implicitly converted to 64 bits
(was 64-bit shift intended?)

If '1UL' is an unsigned 32-bit value, the result of shifting it by more
than 32 bits is *undefined*. The compiler isn't obliged to convert it
to a 64-bit value for us — hence the warning. We're lucky it noticed,
in fact.

Make the value explicitly 64-bit before doing the shift, and everything
should be OK. We do it by casting to (uint64_t) since support for the
ULL suffix isn't ubiquitous,

---
In fact perhaps this could be expressed differently as 
   if (N >> (16 * r))
but I figured I'd leave it in basically its original form.

 crypto/evp/scrypt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/evp/scrypt.c b/crypto/evp/scrypt.c
index 09dfdf2..4254abf 100644
--- a/crypto/evp/scrypt.c
+++ b/crypto/evp/scrypt.c
@@ -227,7 +227,7 @@ int EVP_PBE_scrypt(const char *pass, size_t passlen,
      */
 
     if (16 * r <= LOG2_UINT64_MAX) {
-        if (N >= (1UL << (16 * r)))
+        if (N >= (((uint64_t)1) << (16 * r)))
             return 0;
     }
 
-- 
2.4.3

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse at intel.com                              Intel Corporation

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