ash: builtin: Mark more regular built-ins

[oweals/busybox.git] / libbb / correct_password.c

diff --git a/libbb/correct_password.c b/libbb/correct_password.c
index d031b2109a6e9f8d8e655324f2f181255b409dfd..cbe6cb38706828aeb7ffb723915c35dbd76c3eaf 100644 (file)
--- a/libbb/correct_password.c
+++ b/libbb/correct_password.c
@@ -15,7 +15,7 @@
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
- * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
+ * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ''AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
@@ -27,38 +27,97 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-
 #include "libbb.h"
 
-/* Ask the user for a password.
-   Return 1 if the user gives the correct password for entry PW,
-   0 if not.  Return 1 without asking for a password if run by UID 0
-   or if PW has an empty password.  */
+#define SHADOW_BUFSIZE 256
 
-int correct_password(const struct passwd *pw)
+/* Retrieve encrypted password string for pw.
+ * If pw == NULL, return a string which fails password check against any
+ * password.
+ */
+#if !ENABLE_FEATURE_SHADOWPASSWDS
+#define get_passwd(pw, buffer) get_passwd(pw)
+#endif
+static const char *get_passwd(const struct passwd *pw, char buffer[SHADOW_BUFSIZE])
 {
-       char *unencrypted, *encrypted, *correct;
+       const char *pass;
 
-#ifdef CONFIG_FEATURE_SHADOWPASSWDS
-       if (LONE_CHAR(pw->pw_passwd, 'x') || LONE_CHAR(pw->pw_passwd, '*')) {
-               struct spwd *sp = getspnam(pw->pw_name);
+       if (!pw)
+               return "aa"; /* "aa" will never match */
 
-               if (!sp)
-                       bb_error_msg_and_die("no valid shadow password");
-
-               correct = sp->sp_pwdp;
-       } else
+       pass = pw->pw_passwd;
+#if ENABLE_FEATURE_SHADOWPASSWDS
+       /* Using _r function to avoid pulling in static buffers */
+       if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
+               struct spwd spw;
+               int r;
+               /* getspnam_r may return 0 yet set result to NULL.
+                * At least glibc 2.4 does this. Be extra paranoid here. */
+               struct spwd *result = NULL;
+               r = getspnam_r(pw->pw_name, &spw, buffer, SHADOW_BUFSIZE, &result);
+               pass = (r || !result) ? "aa" : result->sp_pwdp;
+       }
 #endif
-               correct = pw->pw_passwd;
+       return pass;
+}
 
-       if (!correct || correct[0] == '\0')
-               return 1;
+/*
+ * Return CHECKPASS_PW_HAS_EMPTY_PASSWORD if PW has an empty password.
+ * Return 1 if the user gives the correct password for entry PW,
+ * 0 if not.
+ * NULL pw means "just fake it for login with bad username"
+ */
+int FAST_FUNC check_password(const struct passwd *pw, const char *plaintext)
+{
+       IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
+       char *encrypted;
+       const char *pw_pass;
+       int r;
 
-       unencrypted = bb_askpass(0, "Password: ");
-       if (!unencrypted) {
-               return 0;
+       pw_pass = get_passwd(pw, buffer);
+       if (!pw_pass[0]) { /* empty password field? */
+               return CHECKPASS_PW_HAS_EMPTY_PASSWORD;
        }
-       encrypted = crypt(unencrypted, correct);
-       memset(unencrypted, 0, strlen(unencrypted));
-       return (!strcmp(encrypted, correct)) ? 1 : 0;
+
+       encrypted = pw_encrypt(plaintext, /*salt:*/ pw_pass, 1);
+       r = (strcmp(encrypted, pw_pass) == 0);
+       free(encrypted);
+       return r;
+}
+
+
+/* Ask the user for a password.
+ * Return CHECKPASS_PW_HAS_EMPTY_PASSWORD without asking if PW has an empty password.
+ * Return -1 on EOF, error while reading input, or timeout.
+ * Return 1 if the user gives the correct password for entry PW,
+ * 0 if not.
+ *
+ * NULL pw means "just fake it for login with bad username"
+ */
+int FAST_FUNC ask_and_check_password_extended(const struct passwd *pw,
+               int timeout, const char *prompt)
+{
+       IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
+       char *plaintext;
+       const char *pw_pass;
+       int r;
+
+       pw_pass = get_passwd(pw, buffer);
+       if (!pw_pass[0]) /* empty password field? */
+               return CHECKPASS_PW_HAS_EMPTY_PASSWORD;
+
+       plaintext = bb_ask_noecho(STDIN_FILENO, timeout, prompt);
+       if (!plaintext) {
+               /* EOF (such as ^D) or error (such as ^C) or timeout */
+               return -1;
+       }
+
+       r = check_password(pw, plaintext);
+       nuke_str(plaintext);
+       return r;
+}
+
+int FAST_FUNC ask_and_check_password(const struct passwd *pw)
+{
+       return ask_and_check_password_extended(pw, 0, "Password: ");
 }