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/contrib/pg_upgrade/dump.c b/contrib/pg_upgrade/dump.c
index a16fb587ca93add3e178125fbd9aa01cdea709bc..83316aa4ae1134d8be4b504069545c671c1490bd 100644 (file)
--- a/contrib/pg_upgrade/dump.c
+++ b/contrib/pg_upgrade/dump.c
@@ -18,7 +18,6 @@ void
 generate_old_dump(void)
 {
    int         dbnum;
-   mode_t      old_umask;
 
    prep_status("Creating dump of global objects");
 
@@ -33,13 +32,6 @@ 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++)
    {
@@ -74,8 +66,6 @@ generate_old_dump(void)
    while (reap_child(true) == true)
        ;
 
-   umask(old_umask);
-
    end_progress_output();
    check_ok();
 }

diff --git a/contrib/pg_upgrade/file.c b/contrib/pg_upgrade/file.c
index e2f8f3d2d1f5ae7a0bc51f16e87a79bfe4b6ef9f..bed9080b42404e96a11ccd35d44f140a1bcd442c 100644 (file)
--- a/contrib/pg_upgrade/file.c
+++ b/contrib/pg_upgrade/file.c
@@ -238,17 +238,3 @@ 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);
-
-   return fp;
-}

diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
index 9fe2def887614b2efdf8691054011528e7c8f4a8..2ee9bad029c5da6e6b5022a1e321fd19ce4b446b 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.c
+++ b/contrib/pg_upgrade/pg_upgrade.c
@@ -82,6 +82,9 @@ 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/contrib/pg_upgrade/pg_upgrade.h b/contrib/pg_upgrade/pg_upgrade.h
index 057d03171d3516383df2bca471940c328a8b3754..b4feef0ef4c043b04c779099f6bc748642326ebf 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.h
+++ b/contrib/pg_upgrade/pg_upgrade.h
@@ -393,7 +393,9 @@ const char *linkAndUpdateFile(pageCnvCtx *pageConverter, const char *src,
                  const char *dst);
 
 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 */