Provide some constant time functions for dealing with size_t values

Also implement the using of them

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/include/internal/constant_time_locl.h b/include/internal/constant_time_locl.h
index d27fb14c80..be2730ea95 100644
--- a/include/internal/constant_time_locl.h
+++ b/include/internal/constant_time_locl.h
@@ -10,6 +10,7 @@
 #ifndef HEADER_CONSTANT_TIME_LOCL_H
 # define HEADER_CONSTANT_TIME_LOCL_H
 
+# include <stdlib.h>
 # include <openssl/e_os2.h>              /* For 'ossl_inline' */
 
 #ifdef __cplusplus
@@ -102,12 +103,22 @@ static ossl_inline unsigned int constant_time_msb(unsigned int a)
     return 0 - (a >> (sizeof(a) * 8 - 1));
 }
 
+static ossl_inline size_t constant_time_msb_s(size_t a)
+{
+    return 0 - (a >> (sizeof(a) * 8 - 1));
+}
+
 static ossl_inline unsigned int constant_time_lt(unsigned int a,
                                                  unsigned int b)
 {
     return constant_time_msb(a ^ ((a ^ b) | ((a - b) ^ b)));
 }
 
+static ossl_inline size_t constant_time_lt_s(size_t a, size_t b)
+{
+    return constant_time_msb_s(a ^ ((a ^ b) | ((a - b) ^ b)));
+}
+
 static ossl_inline unsigned char constant_time_lt_8(unsigned int a,
                                                     unsigned int b)
 {
@@ -120,17 +131,32 @@ static ossl_inline unsigned int constant_time_ge(unsigned int a,
     return ~constant_time_lt(a, b);
 }
 
+static ossl_inline size_t constant_time_ge_s(size_t a, size_t b)
+{
+    return ~constant_time_lt_s(a, b);
+}
+
 static ossl_inline unsigned char constant_time_ge_8(unsigned int a,
                                                     unsigned int b)
 {
     return (unsigned char)(constant_time_ge(a, b));
 }
 
+static ossl_inline unsigned char constant_time_ge_8_s(size_t a, size_t b)
+{
+    return (unsigned char)(constant_time_ge_s(a, b));
+}
+
 static ossl_inline unsigned int constant_time_is_zero(unsigned int a)
 {
     return constant_time_msb(~a & (a - 1));
 }
 
+static ossl_inline size_t constant_time_is_zero_s(size_t a)
+{
+    return constant_time_msb_s(~a & (a - 1));
+}
+
 static ossl_inline unsigned char constant_time_is_zero_8(unsigned int a)
 {
     return (unsigned char)(constant_time_is_zero(a));
@@ -142,12 +168,22 @@ static ossl_inline unsigned int constant_time_eq(unsigned int a,
     return constant_time_is_zero(a ^ b);
 }
 
+static ossl_inline size_t constant_time_eq_s(size_t a, size_t b)
+{
+    return constant_time_is_zero_s(a ^ b);
+}
+
 static ossl_inline unsigned char constant_time_eq_8(unsigned int a,
                                                     unsigned int b)
 {
     return (unsigned char)(constant_time_eq(a, b));
 }
 
+static ossl_inline unsigned char constant_time_eq_8_s(size_t a, size_t b)
+{
+    return (unsigned char)(constant_time_eq_s(a, b));
+}
+
 static ossl_inline unsigned int constant_time_eq_int(int a, int b)
 {
     return constant_time_eq((unsigned)(a), (unsigned)(b));
@@ -165,6 +201,13 @@ static ossl_inline unsigned int constant_time_select(unsigned int mask,
     return (mask & a) | (~mask & b);
 }
 
+static ossl_inline size_t constant_time_select_s(size_t mask,
+                                                 size_t a,
+                                                 size_t b)
+{
+    return (mask & a) | (~mask & b);
+}
+
 static ossl_inline unsigned char constant_time_select_8(unsigned char mask,
                                                         unsigned char a,
                                                         unsigned char b)
@@ -178,6 +221,12 @@ static ossl_inline int constant_time_select_int(unsigned int mask, int a,
     return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b)));
 }
 
+static ossl_inline int constant_time_select_int_s(size_t mask, int a, int b)
+{
+    return (int)(constant_time_select((unsigned)mask, (unsigned)(a),
+                                      (unsigned)(b)));
+}
+
 #ifdef __cplusplus
 }
 #endif