Renamed generate_encryption_keys binary to libexim-encrypt-dlfunc-genkeys.

src/libexim-encrypt-dlfunc-genkeys.c

@@ -0,0 +1,154 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <sodium.h>
+
+bool key_contains_zero(unsigned char *key, unsigned int keylen)
+{
+	bool has_zero = false;
+	for (unsigned int i = 0; i < keylen; i++) {
+		if (key[i] == 0) {
+			has_zero = true;
+		}
+	}
+	return has_zero;
+}
+
+void
+dump_key_as_c_code(FILE * f, const char *name, unsigned char *key,
+		   unsigned int keylen)
+{
+	fprintf(f, "const unsigned char %s[] = { ", name);
+	for (unsigned int i = 0; i < keylen; i++) {
+		fprintf(f, "0x%02x", key[i]);
+		if (i < keylen - 1) {
+			fprintf(f, ", ");
+		}
+	}
+	fprintf(f, " };\n");
+	fprintf(f, "const unsigned int %s_length = %d;\n", name, keylen);
+}
+
+void
+dump_key_as_exim_config(FILE * f, const char *name, unsigned char *key,
+			unsigned int keylen)
+{
+    // write a comment with C variable declaration
+    fprintf(f, "# const unsigned char %s[%d] = { ", name, keylen);
+    for (unsigned int i = 0; i < keylen; i++) {
+        fprintf(f, "0x%02x", key[i]);
+        if (i < keylen - 1) {
+            fprintf(f, ", ");
+        }
+    }
+    fprintf(f, " }; const unsigned int %s_length = %d;\n", name, keylen);
+
+    // encode with base64
+    unsigned int b64len = sodium_base64_ENCODED_LEN(keylen, sodium_base64_VARIANT_ORIGINAL);
+    unsigned char *b64string = malloc(b64len);
+    sodium_bin2base64((char *const) b64string, b64len,
+                      key, keylen,
+                      sodium_base64_VARIANT_ORIGINAL);
+    // generate uppercase version of variable name
+    size_t namelen = strlen(name);
+    char * nameupper = malloc(namelen);
+    for (unsigned int i = 0; i < namelen; i++) {
+        nameupper[i] = toupper((unsigned char) name[i]);
+    }
+
+    fprintf(f, "%s=%s\n", nameupper, b64string);
+
+    free(b64string);
+}
+
+void
+write_key_files(const char *filebase, const char *varname,
+		unsigned char *key, unsigned int keylen)
+{
+	char header_filename[4096];
+	char exim_filename[4096];
+	char raw_filename[4096];
+	FILE *f;
+
+	sprintf(header_filename, "%s.h", filebase);
+	sprintf(exim_filename, "%s_exim.conf", filebase);
+	sprintf(raw_filename, "%s.raw", filebase);
+
+	// open exim config snippet file
+	f = fopen(exim_filename, "w+");
+	if (f == NULL) {
+		fprintf(stderr, "Unable to open %s for writing", exim_filename);
+		exit(129);
+	}
+	// write key as exim config
+	dump_key_as_exim_config(f, varname, key, keylen);
+	fprintf(stderr, "  Wrote »%s«\n", exim_filename);
+
+	// close exim file
+	fclose(f);
+
+	// open raw file
+	f = fopen(raw_filename, "w+");
+	if (f == NULL) {
+		fprintf(stderr, "Unable to open %s for writing", raw_filename);
+		exit(129);
+	}
+	// write key
+	fwrite(key, sizeof(key[0]), keylen, f);
+	fprintf(stderr, "  Wrote »%s«\n", raw_filename);
+
+	// close raw file
+	fclose(f);
+
+}
+
+void create_cryptobox_keys(const char *filebase, const char *varname)
+{
+	unsigned char recipient_pk[crypto_box_PUBLICKEYBYTES];
+	unsigned char recipient_sk[crypto_box_SECRETKEYBYTES];
+
+    crypto_box_keypair(recipient_pk, recipient_sk);
+
+	char pk_filename[4096];
+	char pk_varname[4096];
+	char sk_filename[4096];
+	char sk_varname[4096];
+
+	sprintf(pk_filename, "%s_pk", filebase);
+	sprintf(pk_varname, "%s_pk", varname);
+	sprintf(sk_filename, "%s_sk", filebase);
+	sprintf(sk_varname, "%s_sk", varname);
+
+	write_key_files(pk_filename, pk_varname,
+			recipient_pk, crypto_box_PUBLICKEYBYTES);
+	write_key_files(sk_filename, sk_varname,
+			recipient_sk, crypto_box_SECRETKEYBYTES);
+
+}
+
+void create_secretbox_key(const char *filebase, const char *varname) {
+    unsigned char key[crypto_secretbox_KEYBYTES];
+
+    crypto_secretbox_keygen(key);
+
+    char key_filename[4096];
+    char key_varname[4096];
+
+    sprintf(key_filename, "%s_secretbox", filebase);
+    sprintf(key_varname, "%s_key", varname);
+
+    write_key_files(key_filename, key_varname, key, crypto_secretbox_KEYBYTES);
+}
+
+int main(void) {
+    if (sodium_init() < 0) {
+        fputs("Unable to initialize libsodium", stderr);
+        exit(128);
+    }
+
+    fputs("=== Creating cryptobox key pair ===\n", stderr);
+    create_cryptobox_keys("cryptobox_recipient", "cryptobox_recipient");
+
+    exit(EXIT_SUCCESS);
+}