Merge pull request #96 from PQClean/test_preprocessor

Test for preprocessor conditionals

.github/pull_request_template.md

@@ -6,7 +6,6 @@
 #### Manually checked properties
 <!-- These checkboxes serve for the maintainers of PQClean to verify your submission. Please do not check them yourself. -->
 
-* [ ] `#if`/`#ifdef`s only for header encapsulation
 * [ ] No stringification macros
 * [ ] Output-parameter pointers in functions are on the left
 * [ ] Negative return values on failure of API functions (within restrictions of FO transform).

README.md

@@ -36,6 +36,7 @@ _The checking of items on this list is still being developed. Checked items shou
 * [x] API functions do not write outside provided buffers
 * [x] `api.h` cannot include external files
 * [x] Compiles with `-Wall -Wextra -Wpedantic -Werror` with `gcc` and `clang`
+* [x] `#if`/`#ifdef`s only for header encapsulation
 * [x] Consistent test vectors across runs
 * [x] Consistent test vectors on big-endian and little-endian machines
 * [x] Consistent test vectors on 32-bit and 64-bit machines
@@ -66,7 +67,6 @@ _The checking of items on this list is still being developed. Checked items shou
 ## Requirements on C implementations that are manually checked
 
 * Minimalist Makefiles
-* `#if`/`#ifdef`s only for header encapsulation
 * No stringification macros
 * Output-parameter pointers in functions are on the left
 * `const` arguments are labeled as `const`

crypto_kem/kyber768/clean/cbd.c

@@ -32,32 +32,6 @@ static uint64_t load_littleendian(const unsigned char *x, int bytes) {
  *              - const unsigned char *buf: pointer to input byte array
  **************************************************/
 void PQCLEAN_KYBER768_CLEAN_cbd(poly *r, const unsigned char *buf) {
-    #if KYBER_ETA == 3
-    uint32_t t, d, a[4], b[4];
-    int i, j;
-
-    for (i = 0; i < KYBER_N / 4; i++) {
-        t = (uint32_t)load_littleendian(buf + 3 * i, 3);
-        d = 0;
-        for (j = 0; j < 3; j++) {
-            d += (t >> j) & 0x249249;
-        }
-
-        a[0] =  d        & 0x7;
-        b[0] = (d >>  3) & 0x7;
-        a[1] = (d >>  6) & 0x7;
-        b[1] = (d >>  9) & 0x7;
-        a[2] = (d >> 12) & 0x7;
-        b[2] = (d >> 15) & 0x7;
-        a[3] = (d >> 18) & 0x7;
-        b[3] = (d >> 21);
-
-        r->coeffs[4 * i + 0] = (uint16_t)(a[0] + KYBER_Q - b[0]);
-        r->coeffs[4 * i + 1] = (uint16_t)(a[1] + KYBER_Q - b[1]);
-        r->coeffs[4 * i + 2] = (uint16_t)(a[2] + KYBER_Q - b[2]);
-        r->coeffs[4 * i + 3] = (uint16_t)(a[3] + KYBER_Q - b[3]);
-    }
-    #elif KYBER_ETA == 4
     uint32_t t, d, a[4], b[4];
     int i, j;
 
@@ -82,32 +56,4 @@ void PQCLEAN_KYBER768_CLEAN_cbd(poly *r, const unsigned char *buf) {
         r->coeffs[4 * i + 2] = (uint16_t)(a[2] + KYBER_Q - b[2]);
         r->coeffs[4 * i + 3] = (uint16_t)(a[3] + KYBER_Q - b[3]);
     }
-    #elif KYBER_ETA == 5
-    uint64_t t, d, a[4], b[4];
-    int i, j;
-
-    for (i = 0; i < KYBER_N / 4; i++) {
-        t = load_littleendian(buf + 5 * i, 5);
-        d = 0;
-        for (j = 0; j < 5; j++) {
-            d += (t >> j) & 0x0842108421UL;
-        }
-
-        a[0] =  d        & 0x1f;
-        b[0] = (d >>  5) & 0x1f;
-        a[1] = (d >> 10) & 0x1f;
-        b[1] = (d >> 15) & 0x1f;
-        a[2] = (d >> 20) & 0x1f;
-        b[2] = (d >> 25) & 0x1f;
-        a[3] = (d >> 30) & 0x1f;
-        b[3] = (d >> 35);
-
-        r->coeffs[4 * i + 0] = (uint16_t)(a[0] + KYBER_Q - b[0]);
-        r->coeffs[4 * i + 1] = (uint16_t)(a[1] + KYBER_Q - b[1]);
-        r->coeffs[4 * i + 2] = (uint16_t)(a[2] + KYBER_Q - b[2]);
-        r->coeffs[4 * i + 3] = (uint16_t)(a[3] + KYBER_Q - b[3]);
-    }
-    #else
-#error "poly_getnoise in poly.c only supports eta in {3,4,5}"
-    #endif
 }

test/test_preprocessor.py

@@ -0,0 +1,37 @@
+import os
+from glob import glob
+
+import pqclean
+from helpers import run_subprocess, ensure_available
+
+
+def test_preprocessor():
+    for scheme in pqclean.Scheme.all_schemes():
+        for implementation in scheme.implementations:
+            yield check_preprocessor, implementation
+
+
+def check_preprocessor(implementation: pqclean.Implementation):
+    cfiles = implementation.cfiles()
+    hfiles = implementation.hfiles()
+    errors = []
+    for file in hfiles + cfiles:
+        with open(file) as f:
+            for i, line in enumerate(f):
+                line = line.strip()
+                if file in hfiles and i == 0 and line.startswith('#ifndef'):
+                    continue
+                if line.startswith('#if'):
+                    errors.append("\n at {}:{}".format(file, i+1))
+    if errors:
+        raise AssertionError(
+            "Prohibited use of preprocessor conditional" + "".join(errors)
+        )
+
+if __name__ == "__main__":
+    try:
+        import nose2
+        nose2.main()
+    except ImportError:
+        import nose
+        nose.runmodule()