1 files changed, 139 insertions, 0 deletions
diff --git a/src/c/openssl.c b/src/c/openssl.c
new file mode 100644
index 0000000..5982b83
--- /dev/null
+++ b/src/c/openssl.c
@@ -0,0 +1,139 @@
+#include "config.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/opensslv.h>
+#include <openssl/sha.h>
+#include <openssl/rand.h>
+
+#define PASSSIZE 4
+
+int uw_hash_blocksize = 32;
+
+static int password[PASSSIZE];
+
+char *uw_sig_file = NULL;
+
+static void random_password() {
+  if (!RAND_bytes((unsigned char *)password, sizeof password)) {
+    fprintf(stderr, "Error generating random password\n");
+    perror("RAND_bytes");
+    exit(1);
+  }
+}
+
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+// We're using OpenSSL <1.1, so we need to specify threading callbacks.  See
+// threads(3SSL).
+
+#include <assert.h>
+#include <pthread.h>
+
+#include <openssl/crypto.h>
+
+static pthread_mutex_t *openssl_locks;
+
+// OpenSSL callbacks
+#ifdef PTHREAD_T_IS_POINTER
+static void thread_id(CRYPTO_THREADID *const result) {
+  CRYPTO_THREADID_set_pointer(result, pthread_self());
+}
+#else
+static void thread_id(CRYPTO_THREADID *const result) {
+  CRYPTO_THREADID_set_numeric(result, (unsigned long)pthread_self());
+}
+#endif
+
+static void lock_or_unlock(const int mode, const int type, const char *file,
+                           const int line) {
+  pthread_mutex_t *const lock = &openssl_locks[type];
+  if (mode & CRYPTO_LOCK) {
+    if (pthread_mutex_lock(lock)) {
+      fprintf(stderr, "Can't take lock at %s:%d\n", file, line);
+      exit(1);
+    }
+  } else {
+    if (pthread_mutex_unlock(lock)) {
+      fprintf(stderr, "Can't release lock at %s:%d\n", file, line);
+      exit(1);
+    }
+  }
+}
+
+static void init_openssl() {
+  int i;
+  // Set up OpenSSL.
+  assert(openssl_locks == NULL);
+  openssl_locks = malloc(CRYPTO_num_locks() * sizeof(pthread_mutex_t));
+  if (!openssl_locks) {
+    perror("malloc");
+    exit(1);
+  }
+  for (i = 0; i < CRYPTO_num_locks(); ++i) {
+    pthread_mutex_init(&(openssl_locks[i]), NULL);
+  }
+  CRYPTO_THREADID_set_callback(thread_id);
+  CRYPTO_set_locking_callback(lock_or_unlock);
+}
+
+#else
+// We're using OpenSSL >=1.1, which is thread-safe by default.  We don't need to
+// do anything here.
+
+static void init_openssl() {}
+
+#endif  // OPENSSL_VERSION_NUMBER < 0x10100000L
+
+void uw_init_crypto() {
+  init_openssl();
+  // Prepare signatures.
+  if (uw_sig_file) {
+    int fd;
+
+    if (access(uw_sig_file, F_OK)) {
+      random_password();
+
+      if ((fd = open(uw_sig_file, O_WRONLY | O_CREAT, 0700)) < 0) {
+        fprintf(stderr, "Can't open signature file %s\n", uw_sig_file);
+        perror("open");
+        exit(1);
+      }
+
+      if (write(fd, &password, sizeof password) != sizeof password) {
+        fprintf(stderr, "Error writing signature file\n");
+        exit(1);
+      }
+
+      close(fd);
+    } else {
+      if ((fd = open(uw_sig_file, O_RDONLY)) < 0) {
+        fprintf(stderr, "Can't open signature file %s\n", uw_sig_file);
+        perror("open");
+        exit(1);
+      }
+
+      if (read(fd, &password, sizeof password) != sizeof password) {
+        fprintf(stderr, "Error reading signature file\n");
+        exit(1);
+      }
+
+      close(fd);
+    }
+  } else
+    random_password();
+}
+
+void uw_sign(const char *in, unsigned char *out) {
+  SHA256_CTX c;
+
+  SHA256_Init(&c);
+  SHA256_Update(&c, password, sizeof password);
+  SHA256_Update(&c, in, strlen(in));
+  SHA256_Final(out, &c);
+}