[tor-commits] [tor/master] Extract numeric CSPRNG functions into a new module.
dgoulet at torproject.org
dgoulet at torproject.org
Thu Feb 14 16:48:44 UTC 2019
commit a49149fc13e8b81e30df17579f19408ae8f4200f
Author: Nick Mathewson <nickm at torproject.org>
Date: Wed Feb 6 12:40:01 2019 -0500
Extract numeric CSPRNG functions into a new module.
Some of the code for getting a random value within a range wants to
be shared between crypto_rand() and the new crypto_fast_rng() code.
---
src/lib/crypt_ops/crypto_rand.c | 108 -----------------------------
src/lib/crypt_ops/crypto_rand_numeric.c | 117 ++++++++++++++++++++++++++++++++
src/lib/crypt_ops/include.am | 1 +
3 files changed, 118 insertions(+), 108 deletions(-)
diff --git a/src/lib/crypt_ops/crypto_rand.c b/src/lib/crypt_ops/crypto_rand.c
index 5a739a8f1..14c2434a8 100644
--- a/src/lib/crypt_ops/crypto_rand.c
+++ b/src/lib/crypt_ops/crypto_rand.c
@@ -539,114 +539,6 @@ crypto_rand_u32(void)
}
/**
- * Return a pseudorandom integer, chosen uniformly from the values
- * between 0 and <b>max</b>-1 inclusive. <b>max</b> must be between 1 and
- * INT_MAX+1, inclusive.
- */
-int
-crypto_rand_int(unsigned int max)
-{
- unsigned int val;
- unsigned int cutoff;
- tor_assert(max <= ((unsigned int)INT_MAX)+1);
- tor_assert(max > 0); /* don't div by 0 */
-
- /* We ignore any values that are >= 'cutoff,' to avoid biasing the
- * distribution with clipping at the upper end of unsigned int's
- * range.
- */
- cutoff = UINT_MAX - (UINT_MAX%max);
- while (1) {
- crypto_rand((char*)&val, sizeof(val));
- if (val < cutoff)
- return val % max;
- }
-}
-
-/**
- * Return a pseudorandom integer, chosen uniformly from the values i such
- * that min <= i < max.
- *
- * <b>min</b> MUST be in range [0, <b>max</b>).
- * <b>max</b> MUST be in range (min, INT_MAX].
- **/
-int
-crypto_rand_int_range(unsigned int min, unsigned int max)
-{
- tor_assert(min < max);
- tor_assert(max <= INT_MAX);
-
- /* The overflow is avoided here because crypto_rand_int() returns a value
- * between 0 and (max - min) inclusive. */
- return min + crypto_rand_int(max - min);
-}
-
-/**
- * As crypto_rand_int_range, but supports uint64_t.
- **/
-uint64_t
-crypto_rand_uint64_range(uint64_t min, uint64_t max)
-{
- tor_assert(min < max);
- return min + crypto_rand_uint64(max - min);
-}
-
-/**
- * As crypto_rand_int_range, but supports time_t.
- **/
-time_t
-crypto_rand_time_range(time_t min, time_t max)
-{
- tor_assert(min < max);
- return min + (time_t)crypto_rand_uint64(max - min);
-}
-
-/**
- * Return a pseudorandom 64-bit integer, chosen uniformly from the values
- * between 0 and <b>max</b>-1 inclusive.
- **/
-uint64_t
-crypto_rand_uint64(uint64_t max)
-{
- uint64_t val;
- uint64_t cutoff;
- tor_assert(max < UINT64_MAX);
- tor_assert(max > 0); /* don't div by 0 */
-
- /* We ignore any values that are >= 'cutoff,' to avoid biasing the
- * distribution with clipping at the upper end of unsigned int's
- * range.
- */
- cutoff = UINT64_MAX - (UINT64_MAX%max);
- while (1) {
- crypto_rand((char*)&val, sizeof(val));
- if (val < cutoff)
- return val % max;
- }
-}
-
-/**
- * Return a pseudorandom double d, chosen uniformly from the range
- * 0.0 <= d < 1.0.
- **/
-double
-crypto_rand_double(void)
-{
- /* We just use an unsigned int here; we don't really care about getting
- * more than 32 bits of resolution */
- unsigned int u;
- crypto_rand((char*)&u, sizeof(u));
-#if SIZEOF_INT == 4
-#define UINT_MAX_AS_DOUBLE 4294967296.0
-#elif SIZEOF_INT == 8
-#define UINT_MAX_AS_DOUBLE 1.8446744073709552e+19
-#else
-#error SIZEOF_INT is neither 4 nor 8
-#endif /* SIZEOF_INT == 4 || ... */
- return ((double)u) / UINT_MAX_AS_DOUBLE;
-}
-
-/**
* Generate and return a new random hostname starting with <b>prefix</b>,
* ending with <b>suffix</b>, and containing no fewer than
* <b>min_rand_len</b> and no more than <b>max_rand_len</b> random base32
diff --git a/src/lib/crypt_ops/crypto_rand_numeric.c b/src/lib/crypt_ops/crypto_rand_numeric.c
new file mode 100644
index 000000000..97fe3bd18
--- /dev/null
+++ b/src/lib/crypt_ops/crypto_rand_numeric.c
@@ -0,0 +1,117 @@
+/**
+ * \file crypto_rand_numeric.c
+ *
+ * \brief Functions for retrieving uniformly distributed numbers
+ * from our PRNGs.
+ **/
+
+#include "lib/crypt_ops/crypto_rand.h"
+#include "lib/log/util_bug.h"
+
+/**
+ * Return a pseudorandom integer, chosen uniformly from the values
+ * between 0 and <b>max</b>-1 inclusive. <b>max</b> must be between 1 and
+ * INT_MAX+1, inclusive.
+ */
+int
+crypto_rand_int(unsigned int max)
+{
+ unsigned int val;
+ unsigned int cutoff;
+ tor_assert(max <= ((unsigned int)INT_MAX)+1);
+ tor_assert(max > 0); /* don't div by 0 */
+
+ /* We ignore any values that are >= 'cutoff,' to avoid biasing the
+ * distribution with clipping at the upper end of unsigned int's
+ * range.
+ */
+ cutoff = UINT_MAX - (UINT_MAX%max);
+ while (1) {
+ crypto_rand((char*)&val, sizeof(val));
+ if (val < cutoff)
+ return val % max;
+ }
+}
+
+/**
+ * Return a pseudorandom integer, chosen uniformly from the values i such
+ * that min <= i < max.
+ *
+ * <b>min</b> MUST be in range [0, <b>max</b>).
+ * <b>max</b> MUST be in range (min, INT_MAX].
+ **/
+int
+crypto_rand_int_range(unsigned int min, unsigned int max)
+{
+ tor_assert(min < max);
+ tor_assert(max <= INT_MAX);
+
+ /* The overflow is avoided here because crypto_rand_int() returns a value
+ * between 0 and (max - min) inclusive. */
+ return min + crypto_rand_int(max - min);
+}
+
+/**
+ * As crypto_rand_int_range, but supports uint64_t.
+ **/
+uint64_t
+crypto_rand_uint64_range(uint64_t min, uint64_t max)
+{
+ tor_assert(min < max);
+ return min + crypto_rand_uint64(max - min);
+}
+
+/**
+ * As crypto_rand_int_range, but supports time_t.
+ **/
+time_t
+crypto_rand_time_range(time_t min, time_t max)
+{
+ tor_assert(min < max);
+ return min + (time_t)crypto_rand_uint64(max - min);
+}
+
+/**
+ * Return a pseudorandom 64-bit integer, chosen uniformly from the values
+ * between 0 and <b>max</b>-1 inclusive.
+ **/
+uint64_t
+crypto_rand_uint64(uint64_t max)
+{
+ uint64_t val;
+ uint64_t cutoff;
+ tor_assert(max < UINT64_MAX);
+ tor_assert(max > 0); /* don't div by 0 */
+
+ /* We ignore any values that are >= 'cutoff,' to avoid biasing the
+ * distribution with clipping at the upper end of unsigned int's
+ * range.
+ */
+ cutoff = UINT64_MAX - (UINT64_MAX%max);
+ while (1) {
+ crypto_rand((char*)&val, sizeof(val));
+ if (val < cutoff)
+ return val % max;
+ }
+}
+
+/**
+ * Return a pseudorandom double d, chosen uniformly from the range
+ * 0.0 <= d < 1.0.
+ **/
+double
+crypto_rand_double(void)
+{
+ /* We just use an unsigned int here; we don't really care about getting
+ * more than 32 bits of resolution */
+ unsigned int u;
+ crypto_rand((char*)&u, sizeof(u));
+#if SIZEOF_INT == 4
+#define UINT_MAX_AS_DOUBLE 4294967296.0
+#elif SIZEOF_INT == 8
+#define UINT_MAX_AS_DOUBLE 1.8446744073709552e+19
+#else
+#error SIZEOF_INT is neither 4 nor 8
+#endif /* SIZEOF_INT == 4 || ... */
+ return ((double)u) / UINT_MAX_AS_DOUBLE;
+}
diff --git a/src/lib/crypt_ops/include.am b/src/lib/crypt_ops/include.am
index d0ccc13bf..19cfee135 100644
--- a/src/lib/crypt_ops/include.am
+++ b/src/lib/crypt_ops/include.am
@@ -17,6 +17,7 @@ src_lib_libtor_crypt_ops_a_SOURCES = \
src/lib/crypt_ops/crypto_ope.c \
src/lib/crypt_ops/crypto_pwbox.c \
src/lib/crypt_ops/crypto_rand.c \
+ src/lib/crypt_ops/crypto_rand_numeric.c \
src/lib/crypt_ops/crypto_rsa.c \
src/lib/crypt_ops/crypto_s2k.c \
src/lib/crypt_ops/crypto_util.c \
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