1 files changed, 125 insertions, 0 deletions
diff --git a/src/rexmpp_digest.c b/src/rexmpp_digest.c
new file mode 100644
index 0000000..c1dd436
--- /dev/null
+++ b/src/rexmpp_digest.c
@@ -0,0 +1,125 @@
+/**
+   @file rexmpp_digest.c
+   @brief Cryptographic functions
+   @author defanor <defanor@uberspace.net>
+   @date 2023
+   @copyright MIT license.
+*/
+
+#include "config.h"
+#include "rexmpp_digest.h"
+
+#if defined(HAVE_GCRYPT)
+#include <gcrypt.h>
+#elif defined(HAVE_NETTLE)
+#include <nettle/nettle-meta.h>
+#include <stdlib.h>
+#elif defined(HAVE_OPENSSL)
+#include <openssl/evp.h>
+#endif
+
+size_t rexmpp_digest_len (rexmpp_digest_algorithm algo) {
+  switch (algo) {
+  case REXMPP_DIGEST_SHA1: return 20;
+  case REXMPP_DIGEST_SHA256: return 32;
+  case REXMPP_DIGEST_SHA3_256: return 32;
+  default: return 0;
+  }
+}
+
+int rexmpp_digest_buffer (rexmpp_digest_algorithm algo,
+                          const void *in,
+                          size_t in_len,
+                          void *out,
+                          size_t out_len)
+{
+  rexmpp_digest_t ctx;
+  int err = rexmpp_digest_init(&ctx, algo);
+  if (err) {
+    return err;
+  }
+  err = rexmpp_digest_update(&ctx, in, in_len);
+  if (err) {
+    return err;
+  }
+  return rexmpp_digest_finish(&ctx, out, out_len);
+}
+
+int rexmpp_digest_init (rexmpp_digest_t *ctx, rexmpp_digest_algorithm algo) {
+#if defined(HAVE_GCRYPT)
+  int gcry_algo = GCRY_MD_NONE;
+  switch (algo) {
+  case REXMPP_DIGEST_SHA1: gcry_algo = GCRY_MD_SHA1; break;
+  case REXMPP_DIGEST_SHA256: gcry_algo = GCRY_MD_SHA256; break;
+  case REXMPP_DIGEST_SHA3_256: gcry_algo = GCRY_MD_SHA3_256; break;
+  default: return -1;
+  }
+  gcry_error_t err = gcry_md_open(ctx, gcry_algo, 0);
+  if (err != GPG_ERR_NO_ERROR) {
+    return -1;
+  }
+#elif defined(HAVE_NETTLE)
+  ctx->nh = NULL;
+  switch (algo) {
+  case REXMPP_DIGEST_SHA1: ctx->nh = &nettle_sha1; break;
+  case REXMPP_DIGEST_SHA256: ctx->nh = &nettle_sha256; break;
+  case REXMPP_DIGEST_SHA3_256: ctx->nh = &nettle_sha3_256; break;
+  default: return -1;
+  }
+  ctx->nh_ctx = malloc(ctx->nh->context_size);
+  ctx->nh->init(ctx->nh_ctx);
+#elif defined(HAVE_OPENSSL)
+  const EVP_MD *md = NULL;
+  switch (algo) {
+  case REXMPP_DIGEST_SHA1: md = EVP_sha1(); break;
+  case REXMPP_DIGEST_SHA256: md = EVP_sha256(); break;
+  case REXMPP_DIGEST_SHA3_256: md = EVP_sha3_256(); break;
+  default: return -1;
+  }
+  *ctx = EVP_MD_CTX_new();
+  if (! EVP_DigestInit(*ctx, md)) {
+    EVP_MD_CTX_free(*ctx);
+    return -1;
+  }
+#endif
+  return 0;
+}
+
+int rexmpp_digest_update (rexmpp_digest_t *ctx, const void *in, size_t len) {
+#if defined(HAVE_GCRYPT)
+  gcry_md_write(*ctx, in, len);
+#elif defined(HAVE_NETTLE)
+  ctx->nh->update(ctx->nh_ctx, len, in);
+#elif defined(HAVE_OPENSSL)
+  if (! EVP_DigestUpdate(*ctx, in, len)) {
+    return -1;
+  }
+#endif
+  return 0;
+}
+
+int rexmpp_digest_finish (rexmpp_digest_t *ctx, void *out, size_t len) {
+  int ret = 0;
+#if defined(HAVE_GCRYPT)
+  if (out != NULL) {
+    unsigned char *result = gcry_md_read(*ctx, 0);
+    if (result != NULL) {
+      memcpy(out, result, len);
+    } else {
+      ret = -1;
+    }
+  }
+  gcry_md_close(*ctx);
+#elif defined(HAVE_NETTLE)
+  ctx->nh->digest(ctx->nh_ctx, len, out);
+  free(ctx->nh_ctx);
+#elif defined(HAVE_OPENSSL)
+  (void)len;
+  if (! EVP_DigestFinal_ex(*ctx, out, NULL)) {
+    ret = -1;
+  }
+  EVP_MD_CTX_free(*ctx);
+  *ctx = NULL;
+#endif
+  return ret;
+}