Ensure that all temp files made during pg_upgrade are non-world-readable.

pg_upgrade has always attempted to ensure that the transient dump files
it creates are inaccessible except to the owner.  However, refactoring
in commit 76a7650c4 broke that for the file containing "pg_dumpall -g"
output; since then, that file was protected according to the process's
default umask.  Since that file may contain role passwords (hopefully
encrypted, but passwords nonetheless), this is a particularly unfortunate
oversight.  Prudent users of pg_upgrade on multiuser systems would
probably run it under a umask tight enough that the issue is moot, but
perhaps some users are depending only on pg_upgrade's umask changes to
protect their data.

To fix this in a future-proof way, let's just tighten the umask at
process start.  There are no files pg_upgrade needs to write at a
weaker security level; and if there were, transiently relaxing the
umask around where they're created would be a safer approach.

Report and patch by Tom Lane; the idea for the fix is due to Noah Misch.
Back-patch to all supported branches.

Security: CVE-2018-1053

diff --git a/src/bin/pg_upgrade/dump.c b/src/bin/pg_upgrade/dump.c
index 81fb72533818619d06dba677a2293bc483225ab3..86892cebd47f81cc7e30e6c98671586e107b6956 100644 (file)
--- a/src/bin/pg_upgrade/dump.c
+++ b/src/bin/pg_upgrade/dump.c
@@ -19,7 +19,6 @@ void
 generate_old_dump(void)
 {
        int                     dbnum;
-       mode_t          old_umask;
 
        prep_status("Creating dump of global objects");
 
@@ -34,13 +33,6 @@ generate_old_dump(void)
 
        prep_status("Creating dump of database schemas\n");
 
-       /*
-        * Set umask for this function, all functions it calls, and all
-        * subprocesses/threads it creates.  We can't use fopen_priv() as Windows
-        * uses threads and umask is process-global.
-        */
-       old_umask = umask(S_IRWXG | S_IRWXO);
-
        /* create per-db dump files */
        for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
        {
@@ -75,8 +67,6 @@ generate_old_dump(void)
        while (reap_child(true) == true)
                ;
 
-       umask(old_umask);
-
        end_progress_output();
        check_ok();
 }

diff --git a/src/bin/pg_upgrade/file.c b/src/bin/pg_upgrade/file.c
index 346192799280485f21527a60c19024db62346e1e..6bb811be69362d3b82619c31b649c9f8ba470430 100644 (file)
--- a/src/bin/pg_upgrade/file.c
+++ b/src/bin/pg_upgrade/file.c
@@ -314,18 +314,3 @@ win32_pghardlink(const char *src, const char *dst)
                return 0;
 }
 #endif
-
-
-/* fopen() file with no group/other permissions */
-FILE *
-fopen_priv(const char *path, const char *mode)
-{
-       mode_t          old_umask = umask(S_IRWXG | S_IRWXO);
-       FILE       *fp;
-
-       fp = fopen(path, mode);
-
-       umask(old_umask);                       /* we assume this can't change errno */
-
-       return fp;
-}

diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index 710b8efb874e6eca5247d051ed0ca3835df59b16..f9f73093f309e61a0e25394262b06d8e5b00d58f 100644 (file)
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -75,6 +75,9 @@ main(int argc, char **argv)
        char       *deletion_script_file_name = NULL;
        bool            live_check = false;
 
+       /* Ensure that all files created by pg_upgrade are non-world-readable */
+       umask(S_IRWXG | S_IRWXO);
+
        parseCommandLine(argc, argv);
 
        get_restricted_token(os_info.progname);

diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 439552c5da728d6a4ceef1da16b467be7b1efeca..9fbdacc53e591f0753240ab7fa1c143ed5d73aec 100644 (file)
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -374,7 +374,9 @@ void linkFile(const char *src, const char *dst,
 void rewriteVisibilityMap(const char *fromfile, const char *tofile,
                                         const char *schemaName, const char *relName);
 void           check_hard_link(void);
-FILE      *fopen_priv(const char *path, const char *mode);
+
+/* fopen_priv() is no longer different from fopen() */
+#define fopen_priv(path, mode) fopen(path, mode)
 
 /* function.c */