src/hash.c: Add thread safe initialization of SipHash seed

5 files changed, 185 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index ffc06f4..088d839 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ MANDIR       = $(SHAREDIR)/man
 EXEC         = ./
 ## Where to store the installation.  Empty by default.
 DESTDIR      =
-LDLIBS       = -lsiphashbs
+LDLIBS       = -lpthread -lsiphashbs
 
 
 
diff --git a/deps.mk b/deps.mk
index ee1bcb4..12678b6 100644
--- a/deps.mk
+++ b/deps.mk
@@ -4,6 +4,7 @@ catalogs.msg = $(catalogs.en.msg)
 
 sources.c = \
 	src/catalog.c \
+	src/hash.c \
 	src/i18n.c \
 	src/lib.c \
 	src/logerr.c \
@@ -18,6 +19,7 @@ sources.c = \
 
 tests.c = \
 	tests/catalog.c \
+	tests/hash.c \
 	tests/i18n.c \
 	tests/lib.c \
 	tests/logerr.c \
@@ -31,6 +33,7 @@ tests.c = \
 	tests/vector.c \
 
 src/catalog.o:	src/catalog.h
+src/hash.o:	src/hash.h
 src/i18n.o:	src/i18n.h
 src/lib.o:	src/lib.h
 src/logerr.o:	src/logerr.h
@@ -44,6 +47,7 @@ src/util.o:	src/util.h
 src/vector.o:	src/vector.h
 
 tests/catalog.o:	src/catalog.c	src/catalog.h
+tests/hash.o:	src/hash.c	src/hash.h
 tests/i18n.o:	src/i18n.c	src/i18n.h
 tests/lib.o:	src/lib.c	src/lib.h
 tests/logerr.o:	src/logerr.c	src/logerr.h
@@ -57,6 +61,7 @@ tests/util.o:	src/util.c	src/util.h
 tests/vector.o:	src/vector.c	src/vector.h
 
 tests/catalog.a:	tests/catalog.o
+tests/hash.a:	tests/hash.o
 tests/i18n.a:	tests/i18n.o
 tests/lib.a:	tests/lib.o
 tests/logerr.a:	tests/logerr.o
@@ -70,6 +75,7 @@ tests/util.a:	tests/util.o
 tests/vector.a:	tests/vector.o
 
 tests/catalog.bin-check:	tests/catalog.bin
+tests/hash.bin-check:	tests/hash.bin
 tests/i18n.bin-check:	tests/i18n.bin
 tests/lib.bin-check:	tests/lib.bin
 tests/logerr.bin-check:	tests/logerr.bin
@@ -84,6 +90,7 @@ tests/vector.bin-check:	tests/vector.bin
 
 
 src/catalog.o: src/logerr.h
+src/hash.o: src/logerr.h src/random.h
 src/i18n.o: src/catalog.h
 src/lib.o: src/logerr.h
 src/logerr.o:
@@ -97,6 +104,7 @@ src/util.o: src/logerr.h
 src/vector.o: src/catalog.h src/i18n.h src/logerr.h src/math.h src/util.h
 
 tests/catalog.o: src/logerr.h src/testing.h src/util.h tests/slurp.h
+tests/hash.o: src/logerr.h src/random.h src/testing.h
 tests/i18n.o: src/catalog.h src/logerr.h
 tests/lib.o: src/logerr.h
 tests/logerr.o: src/testing.h src/util.h tests/slurp.h
@@ -110,6 +118,7 @@ tests/util.o: src/logerr.h src/testing.h tests/slurp.h
 tests/vector.o: src/catalog.h src/i18n.h src/logerr.h src/math.h src/util.h src/testing.h
 
 tests/catalog.a: src/logerr.o src/testing.o src/util.o tests/slurp.o
+tests/hash.a: src/logerr.o src/random.o src/testing.o src/util.o
 tests/i18n.a: src/catalog.o src/logerr.o
 tests/lib.a: src/logerr.o
 tests/logerr.a: src/testing.o src/util.o tests/slurp.o
diff --git a/src/hash.c b/src/hash.c
new file mode 100644
index 0000000..4b397bd
--- /dev/null
+++ b/src/hash.c
@@ -0,0 +1,104 @@
+#include "config.h"
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <siphashbs.h>
+
+#include "hash.h"
+#include "logerr.h"
+#include "random.h"
+
+
+
+static volatile bool
+INITIALIZED = false;
+
+static uint8_t
+SIPHASH_KEY[SIPHASH_KEY_LENGTH];
+
+static pthread_mutex_t
+SEED_MUTEX = PTHREAD_MUTEX_INITIALIZER;
+
+
+
+static int
+unsafe_init(void) {
+	int rc = -1;
+
+	if (urandom_bytes(SIPHASH_KEY_LENGTH, &SIPHASH_KEY)) {
+		logerr("urandom_bytes()");
+		goto out;
+	}
+
+	rc = 0;
+out:
+	return rc;
+}
+
+static int
+safe_init(void) {
+	int rc = -1;
+
+	bool lock_acquired = false;
+
+	if (INITIALIZED == true) {
+		rc = 0;
+		goto out;
+	}
+
+	const int ret1 = pthread_mutex_lock(&SEED_MUTEX);
+	if (ret1) {
+		logerr("pthread_mutex_lock(): %s", strerror(ret1));
+		goto out;
+	}
+	lock_acquired = true;
+
+	if (INITIALIZED == true) {
+		rc = 0;
+		goto out;
+	}
+
+	if (unsafe_init()) {
+		logerr("unsafe_init()");
+		goto out;
+	}
+
+	INITIALIZED = true;
+
+	rc = 0;
+out:
+	if (lock_acquired) {
+		const int ret2 = pthread_mutex_unlock(&SEED_MUTEX);
+		if (ret2) {
+			logerr("pthread_mutex_unlock(): %s", strerror(ret2));
+			rc = -1;
+		}
+	}
+	return rc;
+}
+
+static void
+ensure_initialized(void) {
+	assert((safe_init() == 0) && "Failed to initialized the hash seed");
+}
+
+int
+hash_init(void) {
+	return safe_init();
+}
+
+void
+hash(
+	const size_t inlen,
+	const void *const restrict in,
+	uint8_t out[HASH_OUTPUT_LENGTH]
+) {
+	ensure_initialized();
+	siphashbs(SIPHASH_KEY, inlen, in, out);
+}
diff --git a/src/hash.h b/src/hash.h
new file mode 100644
index 0000000..4831c4b
--- /dev/null
+++ b/src/hash.h
@@ -0,0 +1,8 @@
+#define HASH_OUTPUT_LENGTH 16U
+
+void
+hash(
+	const size_t inlen,
+	const void *const restrict in,
+	uint8_t out[HASH_OUTPUT_LENGTH]
+);
diff --git a/tests/hash.c b/tests/hash.c
new file mode 100644
index 0000000..652b4fd
--- /dev/null
+++ b/tests/hash.c
@@ -0,0 +1,63 @@
+#include "../src/hash.c"
+
+#include <stdlib.h>
+
+#include "../src/testing.h"
+
+
+
+static void
+test_HASH_OUTPUT_LENGTH(void) {
+	test_start("HASH_OUTPUT_LENGTH");
+
+	{
+		testing("Enforce we're always consistent with SipHash");
+
+		assert(HASH_OUTPUT_LENGTH == SIPHASH_OUTPUT_LENGTH);
+
+		test_ok();
+	}
+}
+
+static int
+test_hash_init(void) {
+	int rc = -1;
+
+	test_start("hash_init()");
+
+	{
+		testing("INITIALIZED changes after calling hash_init()");
+
+		assert(INITIALIZED == false);
+
+		if (hash_init()) {
+			logerr("hash_init()");
+			goto out;
+		}
+		rc = 0; goto out;
+
+		assert(INITIALIZED == true);
+
+		test_ok();
+	}
+
+	rc = 0;
+out:
+	return rc;
+}
+
+int
+main(void) {
+	int rc = EXIT_FAILURE;
+
+	test_HASH_OUTPUT_LENGTH();
+
+	if (test_hash_init()) {
+		logerr("test_hash_init()");
+		goto out;
+	}
+
+	rc = EXIT_SUCCESS;
+out:
+	return rc;
+}