1 files changed, 236 insertions, 0 deletions
diff --git a/src/nvim/crypt.c b/src/nvim/crypt.c
new file mode 100644
index 0000000000..72d4a89c63
--- /dev/null
+++ b/src/nvim/crypt.c
@@ -0,0 +1,236 @@
+// Optional encryption support.
+// Mohsin Ahmed, mosh@sasi.com, 98-09-24
+// Based on zip/crypt sources.
+//
+// NOTE FOR USA: Since 2000 exporting this code from the USA is allowed to
+// most countries. There are a few exceptions, but that still should not be a
+// problem since this code was originally created in Europe and India.
+//
+// Blowfish addition originally made by Mohsin Ahmed,
+// http://www.cs.albany.edu/~mosh 2010-03-14
+// Based on blowfish by Bruce Schneier (http://www.schneier.com/blowfish.html)
+// and sha256 by Christophe Devine.
+
+#include "vim.h"
+#include "misc2.h"
+#include "blowfish.h"
+#include "ex_getln.h"
+#include "message.h"
+#include "option.h"
+
+static void make_crc_tab(void);
+
+static uint32_t crc_32_tab[256];
+
+// Fills the CRC table.
+static void make_crc_tab(void)
+{
+  uint32_t s;
+  uint32_t t;
+  uint32_t v;
+  static bool done = false;
+
+  if (done) {
+    return;
+  }
+
+  for (t = 0; t < 256; t++) {
+    v = t;
+
+    for (s = 0; s < 8; s++) {
+      v = (v >> 1) ^ ((v & 1) * (uint32_t)0xedb88320L);
+    }
+    crc_32_tab[t] = v;
+  }
+  done = true;
+}
+
+#define CRC32(c, b) (crc_32_tab[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
+
+static uint32_t keys[3]; // keys defining the pseudo-random sequence
+
+// Returns the next byte in the pseudo-random sequence.
+#define DECRYPT_BYTE_ZIP(t) { \
+  uint16_t temp; \
+  temp = (uint16_t)keys[2] | 2; \
+  t = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff); \
+}
+
+// Updates the encryption keys with the next byte of plain text.
+#define UPDATE_KEYS_ZIP(c) { \
+  keys[0] = CRC32(keys[0], (c)); \
+  keys[1] += keys[0] & 0xff; \
+  keys[1] = keys[1] * 134775813L + 1; \
+  keys[2] = CRC32(keys[2], (int)(keys[1] >> 24)); \
+}
+
+static int crypt_busy = 0;
+static uint32_t saved_keys[3];
+static int saved_crypt_method;
+
+int crypt_method_from_string(char_u *s)
+{
+  return *s == 'b' ? 1 : 0;
+}
+
+int get_crypt_method(buf_T *buf)
+{
+  return crypt_method_from_string(*buf->b_p_cm == NUL ? p_cm : buf->b_p_cm);
+}
+
+void set_crypt_method(buf_T *buf, int method)
+{
+  free_string_option(buf->b_p_cm);
+  buf->b_p_cm = vim_strsave((char_u *)(method == 0 ? "zip" : "blowfish"));
+}
+
+void crypt_push_state(void)
+{
+  if (crypt_busy == 1) {
+    // Save the state
+    if (use_crypt_method == 0) {
+      saved_keys[0] = keys[0];
+      saved_keys[1] = keys[1];
+      saved_keys[2] = keys[2];
+    } else {
+      bf_crypt_save();
+    }
+    saved_crypt_method = use_crypt_method;
+  } else if (crypt_busy > 1) {
+    EMSG2(_(e_intern2), "crypt_push_state()");
+  }
+  crypt_busy++;
+}
+
+void crypt_pop_state(void)
+{
+  crypt_busy--;
+
+  if (crypt_busy == 1) {
+    use_crypt_method = saved_crypt_method;
+
+    if (use_crypt_method == 0) {
+      keys[0] = saved_keys[0];
+      keys[1] = saved_keys[1];
+      keys[2] = saved_keys[2];
+    } else {
+      bf_crypt_restore();
+    }
+  }
+}
+
+void crypt_encode(char_u *from, size_t len, char_u *to)
+{
+  size_t i;
+  int ztemp;
+  int t;
+
+  if (use_crypt_method == 0) {
+    for (i = 0; i < len; i++) {
+      ztemp = from[i];
+      DECRYPT_BYTE_ZIP(t);
+      UPDATE_KEYS_ZIP(ztemp);
+      to[i] = t ^ ztemp;
+    }
+  } else {
+    bf_crypt_encode(from, len, to);
+  }
+}
+
+void crypt_decode(char_u *ptr, long len)
+{
+  char_u *p;
+
+  if (use_crypt_method == 0) {
+    for (p = ptr; p < ptr + len; p++) {
+      uint16_t temp;
+
+      temp = (uint16_t)keys[2] | 2;
+      temp = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff);
+      UPDATE_KEYS_ZIP(*p ^= temp);
+    }
+  } else {
+    bf_crypt_decode(ptr, len);
+  }
+}
+
+void crypt_init_keys(char_u *passwd)
+{
+  if ((passwd != NULL) && (*passwd != NUL)) {
+    if (use_crypt_method == 0) {
+      char_u *p;
+
+      make_crc_tab();
+      keys[0] = 305419896L;
+      keys[1] = 591751049L;
+      keys[2] = 878082192L;
+
+      for (p = passwd; *p != NUL; p++) {
+        UPDATE_KEYS_ZIP((int)*p);
+      }
+    } else {
+      bf_crypt_init_keys(passwd);
+    }
+  }
+}
+
+void free_crypt_key(char_u *key)
+{
+  char_u *p;
+
+  if (key != NULL) {
+    for (p = key; *p != NUL; p++) {
+      *p = 0;
+    }
+    free(key);
+  }
+}
+
+char_u *get_crypt_key(int store, int twice)
+{
+  char_u *p1;
+  char_u *p2 = NULL;
+  int round;
+
+  for (round = 0;; round++) {
+    cmdline_star = TRUE;
+    cmdline_row = msg_row;
+    char_u *prompt = (round == 0)
+        ? (char_u *) _("Enter encryption key: ")
+        : (char_u *) _("Enter same key again: ");
+    p1 = getcmdline_prompt(NUL, prompt, 0, EXPAND_NOTHING, NULL);
+    cmdline_star = FALSE;
+    if (p1 == NULL) {
+      break;
+    }
+
+    if (round == twice) {
+      if ((p2 != NULL) && (STRCMP(p1, p2) != 0)) {
+        MSG(_("Keys don't match!"));
+        free_crypt_key(p1);
+        free_crypt_key(p2);
+        p2 = NULL;
+        round = -1; // Do it again
+        continue;
+      }
+
+      if (store) {
+        set_option_value((char_u *) "key", 0L, p1, OPT_LOCAL);
+        free_crypt_key(p1);
+        p1 = curbuf->b_p_key;
+      }
+      break;
+    }
+    p2 = p1;
+  }
+
+  // Since the user typed this, no need to wait for return.
+  if (msg_didout) {
+    msg_putchar('\n');
+  }
+  need_wait_return = FALSE;
+  msg_didout = FALSE;
+
+  free_crypt_key(p2);
+  return p1;
+}