passwd: fix bug: we are trying to update shadow even if user's record is in passwd!

getspnam is guilty, it lies that user record exists in shadow.

2 files changed, 19 insertions, 9 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 82cee38..b438ec2 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -482,10 +482,10 @@ int get_uidgid(struct bb_uidgid_t*, const char*, int numeric_ok);
 /* chown-like handling of "user[:[group]" */
 void parse_chown_usergroup_or_die(struct bb_uidgid_t *u, char *user_group);
 /* bb_getpwuid, bb_getgrgid:
-bb_getXXXid(buf, bufsz, id) - copy user/group name or id
-                as a string to buf, return user/group name or NULL
-bb_getXXXid(NULL, 0, id) - return user/group name or NULL
-bb_getXXXid(NULL, -1, id) - return user/group name or exit
+ * bb_getXXXid(buf, bufsz, id) - copy user/group name or id
+ *              as a string to buf, return user/group name or NULL
+ * bb_getXXXid(NULL, 0, id) - return user/group name or NULL
+ * bb_getXXXid(NULL, -1, id) - return user/group name or exit
 */
 char *bb_getpwuid(char *name, int bufsize, long uid);
 char *bb_getgrgid(char *group, int bufsize, long gid);
diff --git a/loginutils/passwd.c b/loginutils/passwd.c
index a293ee9..4f7094a 100644
--- a/loginutils/passwd.c
+++ b/loginutils/passwd.c
@@ -127,15 +127,16 @@ int passwd_main(int argc, char **argv)
 		bb_error_msg_and_die("%s can't change password for %s", myname, name);
 	}
 
-	filename = bb_path_passwd_file;
 #if ENABLE_FEATURE_SHADOWPASSWDS
-	if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)) {
+	/* getspnam_r() can lie! Even if user isn't in shadow, it can
+	 * return success (pwd field was seen set to "!" in this case) */
+	if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)
+	 || LONE_CHAR(spw.sp_pwdp, '!')) {
 		/* LOGMODE_BOTH */
 		bb_error_msg("no record of %s in %s, using %s",
 				name, bb_path_shadow_file,
 				bb_path_passwd_file);
 	} else {
-		filename = bb_path_shadow_file;
 		pw->pw_passwd = spw.sp_pwdp;
 	}
 #endif
@@ -175,8 +176,17 @@ int passwd_main(int argc, char **argv)
 	signal(SIGQUIT, SIG_IGN);
 	umask(077);
 	xsetuid(0);
-	rc = update_passwd(filename, name, newp);
-	logmode = LOGMODE_BOTH;
+
+#if ENABLE_FEATURE_SHADOWPASSWDS
+	filename = bb_path_shadow_file;
+	rc = update_passwd(bb_path_shadow_file, name, newp);
+	if (rc == 0) /* no lines updated, no errors detected */
+#endif
+	{
+		filename = bb_path_passwd_file;
+		rc = update_passwd(bb_path_passwd_file, name, newp);
+	}
+	/* LOGMODE_BOTH */
 	if (rc < 0)
 		bb_error_msg_and_die("cannot update password file %s",
 				filename);