postfix-2.6-20080814

diff --git a/postfix/HISTORY b/postfix/HISTORY
index 310cc6ad0742b12950b2d5c095b474c4a9960fa0..3cd0526ebb4b68f4e5345dfdb924e1740ad346b5 100644 (file)
--- a/postfix/HISTORY
+++ b/postfix/HISTORY
@@ -14549,3 +14549,23 @@ Apologies for any names omitted.
        Paranoia: defer delivery when a mailbox file is not owned
        by the recipient. Sebastian Krahmer, SuSE.  Files:
        local/mailbox.c, virtual/mailbox.c.
+
+20080804
+
+       Bugfix: dangling pointer in vstring_sprintf_prepend().
+       File: util/vstring.c.
+
+20080814
+
+       Security: some systems have changed their link() semantics,
+       and will hardlink a symlink, contrary to POSIX and XPG4.
+       Sebastian Krahmer, SuSE. File: util/safe_open.c.
+
+       The solution introduces the following incompatible change:
+       when the target of mail delivery is a symlink, the parent
+       directory of that symlink must now be writable by root only
+       (in addition to the already existing requirement that the
+       symlink itself is owned by root).  This change will break
+       legitimate configurations that deliver mail to a symbolic
+       link in a directory with less restrictive permissions.
+

diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h
index 8619819747ff26a8a9bc2e727d153c84f77d12bc..23eae826143eda9ca22e04a7d6e994bf6b9566ce 100644 (file)
--- a/postfix/src/global/mail_version.h
+++ b/postfix/src/global/mail_version.h
@@ -20,7 +20,7 @@
   * Patches change both the patchlevel and the release date. Snapshots have no
   * patchlevel; they change the release date only.
   */
-#define MAIL_RELEASE_DATE      "20080726"
+#define MAIL_RELEASE_DATE      "20080814"
 #define MAIL_VERSION_NUMBER    "2.6"
 
 #ifdef SNAPSHOT

diff --git a/postfix/src/util/safe_open.c b/postfix/src/util/safe_open.c
index c825493caad28a0a98f49009a9ba051270b7a9a4..9cf5d0263033e17f28a30f36965d9186b49d0461 100644 (file)
--- a/postfix/src/util/safe_open.c
+++ b/postfix/src/util/safe_open.c
@@ -83,6 +83,7 @@
 #include <msg.h>
 #include <vstream.h>
 #include <vstring.h>
+#include <stringops.h>
 #include <safe_open.h>
 
 /* safe_open_exist - open existing file */
@@ -138,13 +139,29 @@ static VSTREAM *safe_open_exist(const char *path, int flags,
      * for symlinks owned by root. NEVER, NEVER, make exceptions for symlinks
      * owned by a non-root user. This would open a security hole when
      * delivering mail to a world-writable mailbox directory.
+     * 
+     * Sebastian Krahmer of SuSE brought to my attention that some systems have
+     * changed their semantics of link(symlink, newpath), such that the
+     * result is a hardlink to the symlink. For this reason, we now also
+     * require that the symlink's parent directory is writable only by root.
      */
     else if (lstat(path, &lstat_st) < 0) {
        vstring_sprintf(why, "file status changed unexpectedly: %m");
        errno = EPERM;
     } else if (S_ISLNK(lstat_st.st_mode)) {
-       if (lstat_st.st_uid == 0)
-           return (fp);
+       if (lstat_st.st_uid == 0) {
+           VSTRING *parent_buf = vstring_alloc(100);
+           const char *parent_path = sane_dirname(parent_buf, path);
+           struct stat parent_st;
+           int     parent_ok;
+
+           parent_ok = (stat(parent_path, &parent_st) == 0     /* not lstat */
+                        && parent_st.st_uid == 0
+                        && (parent_st.st_mode & (S_IWGRP | S_IWOTH)) == 0);
+           vstring_free(parent_buf);
+           if (parent_ok)
+               return (fp);
+       }
        vstring_sprintf(why, "file is a symbolic link");
        errno = EPERM;
     } else if (fstat_st->st_dev != lstat_st.st_dev

diff --git a/postfix/src/util/vstring.c b/postfix/src/util/vstring.c
index df65a69bca62e7e06b7b2c558c595f59218f2a6d..2a32343970cd890f134206c7760ed9041bffc119 100644 (file)
--- a/postfix/src/util/vstring.c
+++ b/postfix/src/util/vstring.c
@@ -624,6 +624,7 @@ VSTRING *vstring_sprintf_prepend(VSTRING *vp, const char *format,...)
     result_len = VSTRING_LEN(vp);
 
     /* Construct: old|new|old|free */
+    VSTRING_SPACE(vp, old_len);
     vstring_memcat(vp, vstring_str(vp), old_len);
 
     /* Construct: new|old|free */