SERVER-27768 Implement HMAC key for signing Logical clock's storage & distribution

4 files changed, 12 insertions, 28 deletions

diff --git a/src/mongo/crypto/SConscript b/src/mongo/crypto/SConscript
index a18405fbce5..b7f06827201 100644
--- a/src/mongo/crypto/SConscript
+++ b/src/mongo/crypto/SConscript
@@ -19,6 +19,7 @@ env.Library('sha1_block',
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/util/secure_compare_memory',
     ])
 
 env.Library(
@@ -45,6 +46,7 @@ env.Library('scramauth',
             ['mechanism_scram.cpp'],
             LIBDEPS=['$BUILD_DIR/mongo/base',
                      '$BUILD_DIR/mongo/base/secure_allocator',
+                     '$BUILD_DIR/mongo/util/secure_compare_memory',
                      '$BUILD_DIR/mongo/util/secure_zero_memory',
                      'sha1_block_${MONGO_CRYPTO}'])
 
diff --git a/src/mongo/crypto/mechanism_scram.cpp b/src/mongo/crypto/mechanism_scram.cpp
index a1b3c69d8fc..b426dda6cbd 100644
--- a/src/mongo/crypto/mechanism_scram.cpp
+++ b/src/mongo/crypto/mechanism_scram.cpp
@@ -34,6 +34,7 @@
 
 #include "mongo/platform/random.h"
 #include "mongo/util/base64.h"
+#include "mongo/util/secure_compare_memory.h"
 #include "mongo/util/secure_zero_memory.h"
 
 namespace mongo {
@@ -41,31 +42,6 @@ namespace scram {
 
 using std::unique_ptr;
 
-namespace {
-/**
- * Compare two arrays of bytes for equality in constant time.
- *
- * This means that the function runs for the same amount of time even if they differ. Unlike memcmp,
- * this function does not exit on the first difference.
- *
- * Returns true if the two arrays are equal.
- *
- * TODO: evaluate if LTO inlines or changes the code flow of this function.
- */
-NOINLINE_DECL
-bool consttimeMemEqual(volatile const unsigned char* s1,  // NOLINT - using volatile to
-                       volatile const unsigned char* s2,  // NOLINT - disable compiler optimizations
-                       size_t length) {
-    unsigned int ret = 0;
-
-    for (size_t i = 0; i < length; ++i) {
-        ret |= s1[i] ^ s2[i];
-    }
-
-    return (1 & ((ret - 1) >> 8));
-}
-}  // namespace
-
 // Compute the SCRAM step Hi() as defined in RFC5802
 static SHA1Block HMACIteration(const unsigned char input[],
                                size_t inputLen,
diff --git a/src/mongo/crypto/sha1_block.cpp b/src/mongo/crypto/sha1_block.cpp
index c978e545b20..9debee81fcc 100644
--- a/src/mongo/crypto/sha1_block.cpp
+++ b/src/mongo/crypto/sha1_block.cpp
@@ -34,6 +34,7 @@
 #include "mongo/bson/bsonobjbuilder.h"
 #include "mongo/util/base64.h"
 #include "mongo/util/mongoutils/str.h"
+#include "mongo/util/secure_compare_memory.h"
 
 namespace mongo {
 
@@ -81,8 +82,12 @@ void SHA1Block::xorInline(const SHA1Block& other) {
     }
 }
 
-bool SHA1Block::operator==(const SHA1Block& rhs) const {
-    return rhs._hash == this->_hash;
+bool SHA1Block::operator==(const SHA1Block& other) const {
+    return consttimeMemEqual(this->_hash.data(), other._hash.data(), kHashLength);
+}
+
+bool SHA1Block::operator!=(const SHA1Block& other) const {
+    return !(*this == other);
 }
 
 }  // namespace mongo
diff --git a/src/mongo/crypto/sha1_block.h b/src/mongo/crypto/sha1_block.h
index 3398cea6018..a228540bcb0 100644
--- a/src/mongo/crypto/sha1_block.h
+++ b/src/mongo/crypto/sha1_block.h
@@ -90,7 +90,8 @@ public:
     void xorInline(const SHA1Block& other);
 
     std::string toString() const;
-    bool operator==(const SHA1Block& rhs) const;
+    bool operator==(const SHA1Block& other) const;
+    bool operator!=(const SHA1Block& other) const;
 
 private:
     HashType _hash;