RT3066: rewrite RSA padding checks to be slightly more constant time.
Also tweak s3_cbc.c to use new constant-time methods.
Also fix memory leaks from internal errors in RSA_padding_check_PKCS1_OAEP_mgf1
This patch is based on the original RT submission by Adam Langley <agl@chromium.org>,
as well as code from BoringSSL and OpenSSL.
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
diff --git a/crypto/constant_time_test.c b/crypto/constant_time_test.c
index 89fad7d..0e51892 100644
--- a/crypto/constant_time_test.c
+++ b/crypto/constant_time_test.c
@@ -50,9 +50,9 @@
#include <stdio.h>
#include <stdlib.h>
-static const unsigned int CONSTTIME_TRUE = ~0;
+static const unsigned int CONSTTIME_TRUE = (unsigned)(~0);
static const unsigned int CONSTTIME_FALSE = 0;
-static const unsigned char CONSTTIME_TRUE_8 = ~0;
+static const unsigned char CONSTTIME_TRUE_8 = 0xff;
static const unsigned char CONSTTIME_FALSE_8 = 0;
static int test_binary_op(unsigned int (*op)(unsigned int a, unsigned int b),
@@ -133,13 +133,86 @@
return 0;
}
+static int test_select(unsigned int a, unsigned int b)
+ {
+ unsigned int selected = constant_time_select(CONSTTIME_TRUE, a, b);
+ if (selected != a)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%du, %du,"
+ "%du): expected %du(first value), got %du\n",
+ CONSTTIME_TRUE, a, b, a, selected);
+ return 1;
+ }
+ selected = constant_time_select(CONSTTIME_FALSE, a, b);
+ if (selected != b)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%du, %du,"
+ "%du): expected %du(second value), got %du\n",
+ CONSTTIME_FALSE, a, b, b, selected);
+ return 1;
+ }
+ return 0;
+ }
+
+static int test_select_8(unsigned char a, unsigned char b)
+ {
+ unsigned char selected = constant_time_select_8(CONSTTIME_TRUE_8, a, b);
+ if (selected != a)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%u, %u,"
+ "%u): expected %u(first value), got %u\n",
+ CONSTTIME_TRUE, a, b, a, selected);
+ return 1;
+ }
+ selected = constant_time_select_8(CONSTTIME_FALSE_8, a, b);
+ if (selected != b)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%u, %u,"
+ "%u): expected %u(second value), got %u\n",
+ CONSTTIME_FALSE, a, b, b, selected);
+ return 1;
+ }
+ return 0;
+ }
+
+static int test_select_int(int a, int b)
+ {
+ int selected = constant_time_select_int(CONSTTIME_TRUE, a, b);
+ if (selected != a)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%du, %d,"
+ "%d): expected %d(first value), got %d\n",
+ CONSTTIME_TRUE, a, b, a, selected);
+ return 1;
+ }
+ selected = constant_time_select_int(CONSTTIME_FALSE, a, b);
+ if (selected != b)
+ {
+ fprintf(stderr, "Test failed for constant_time_select(%du, %d,"
+ "%d): expected %d(second value), got %d\n",
+ CONSTTIME_FALSE, a, b, b, selected);
+ return 1;
+ }
+ return 0;
+ }
+
+
static unsigned int test_values[] = {0, 1, 1024, 12345, 32000, UINT_MAX/2-1,
UINT_MAX/2, UINT_MAX/2+1, UINT_MAX-1,
UINT_MAX};
+static unsigned char test_values_8[] = {0, 1, 2, 20, 32, 127, 128, 129, 255};
+
+static int signed_test_values[] = {0, 1, -1, 1024, -1024, 12345, -12345,
+ 32000, -32000, INT_MAX, INT_MIN, INT_MAX-1,
+ INT_MIN+1};
+
+
int main(int argc, char *argv[])
{
unsigned int a, b, i, j;
+ int c, d;
+ unsigned char e, f;
int num_failed = 0, num_all = 0;
fprintf(stdout, "Testing constant time operations...\n");
@@ -148,20 +221,8 @@
a = test_values[i];
num_failed += test_is_zero(a);
num_failed += test_is_zero_8(a);
- num_failed += test_binary_op(&constant_time_lt,
- "constant_time_lt", a, a, 0);
- num_failed += test_binary_op_8(&constant_time_lt_8,
- "constant_time_lt_8", a, a, 0);
- num_failed += test_binary_op(&constant_time_ge,
- "constant_time_ge", a, a, 1);
- num_failed += test_binary_op_8(&constant_time_ge_8,
- "constant_time_ge_8", a, a, 1);
- num_failed += test_binary_op(&constant_time_eq,
- "constant_time_eq", a, a, 1);
- num_failed += test_binary_op_8(&constant_time_eq_8,
- "constant_time_eq_8", a, a, 1);
- num_all += 8;
- for (j = i + 1; j < sizeof(test_values)/sizeof(int); ++j)
+ num_all += 2;
+ for (j = 0; j < sizeof(test_values)/sizeof(int); ++j)
{
b = test_values[j];
num_failed += test_binary_op(&constant_time_lt,
@@ -188,7 +249,30 @@
"constant_time_eq", b, a, b == a);
num_failed += test_binary_op_8(&constant_time_eq_8,
"constant_time_eq_8", b, a, b == a);
- num_all += 12;
+ num_failed += test_select(a, b);
+ num_all += 13;
+ }
+ }
+
+ for (i = 0; i < sizeof(signed_test_values)/sizeof(int); ++i)
+ {
+ c = signed_test_values[i];
+ for (j = 0; j < sizeof(signed_test_values)/sizeof(int); ++j)
+ {
+ d = signed_test_values[j];
+ num_failed += test_select_int(c, d);
+ num_all += 1;
+ }
+ }
+
+ for (i = 0; i < sizeof(test_values_8); ++i)
+ {
+ e = test_values_8[i];
+ for (j = 0; j < sizeof(test_values_8); ++j)
+ {
+ f = test_values_8[j];
+ num_failed += test_select_8(e, f);
+ num_all += 1;
}
}
