Make be-secure-common.c more consistent for future SSL implementations

Recent commit 8a3d9425 has introduced be-secure-common.c, which is aimed
at including backend-side APIs that can be used by any SSL
implementation.  The purpose is similar to fe-secure-common.c for the
frontend-side APIs.

However, this has forgotten to include check_ssl_key_file_permissions()
in the move, which causes a double dependency between be-secure.c and
be-secure-openssl.c.

Refactor the code in a more logical way.  This also puts into light an
API which is usable by future SSL implementations for permissions on SSL
key files.

Author: Michael Paquier <michael@paquier.xyz>
This commit is contained in:
Peter Eisentraut 2018-04-02 11:34:52 -04:00
parent 7e0d64c7a5
commit 2764d5dcfa
3 changed files with 76 additions and 70 deletions

View File

@ -19,6 +19,9 @@
#include "postgres.h"
#include <sys/stat.h>
#include <unistd.h>
#include "libpq/libpq.h"
#include "storage/fd.h"
@ -118,3 +121,74 @@ error:
pfree(command.data);
return len;
}
/*
* Check permissions for SSL key files.
*/
bool
check_ssl_key_file_permissions(const char *ssl_key_file, bool isServerStart)
{
int loglevel = isServerStart ? FATAL : LOG;
struct stat buf;
if (stat(ssl_key_file, &buf) != 0)
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("could not access private key file \"%s\": %m",
ssl_key_file)));
return false;
}
if (!S_ISREG(buf.st_mode))
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" is not a regular file",
ssl_key_file)));
return false;
}
/*
* Refuse to load key files owned by users other than us or root.
*
* XXX surely we can check this on Windows somehow, too.
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
if (buf.st_uid != geteuid() && buf.st_uid != 0)
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" must be owned by the database user or root",
ssl_key_file)));
return false;
}
#endif
/*
* Require no public access to key file. If the file is owned by us,
* require mode 0600 or less. If owned by root, require 0640 or less to
* allow read access through our gid, or a supplementary gid that allows
* to read system-wide certificates.
*
* XXX temporarily suppress check when on Windows, because there may not
* be proper support for Unix-y file permissions. Need to think of a
* reasonable check to apply on Windows. (See also the data directory
* permission check in postmaster.c)
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
if ((buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG | S_IRWXO)) ||
(buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO)))
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" has group or world access",
ssl_key_file),
errdetail("File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root.")));
return false;
}
#endif
return true;
}

View File

@ -18,12 +18,10 @@
#include "postgres.h"
#include <sys/stat.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/in.h>
#ifdef HAVE_NETINET_TCP_H
@ -320,70 +318,3 @@ secure_raw_write(Port *port, const void *ptr, size_t len)
return n;
}
bool
check_ssl_key_file_permissions(const char *ssl_key_file, bool isServerStart)
{
int loglevel = isServerStart ? FATAL : LOG;
struct stat buf;
if (stat(ssl_key_file, &buf) != 0)
{
ereport(loglevel,
(errcode_for_file_access(),
errmsg("could not access private key file \"%s\": %m",
ssl_key_file)));
return false;
}
if (!S_ISREG(buf.st_mode))
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" is not a regular file",
ssl_key_file)));
return false;
}
/*
* Refuse to load key files owned by users other than us or root.
*
* XXX surely we can check this on Windows somehow, too.
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
if (buf.st_uid != geteuid() && buf.st_uid != 0)
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" must be owned by the database user or root",
ssl_key_file)));
return false;
}
#endif
/*
* Require no public access to key file. If the file is owned by us,
* require mode 0600 or less. If owned by root, require 0640 or less to
* allow read access through our gid, or a supplementary gid that allows
* to read system-wide certificates.
*
* XXX temporarily suppress check when on Windows, because there may not
* be proper support for Unix-y file permissions. Need to think of a
* reasonable check to apply on Windows. (See also the data directory
* permission check in postmaster.c)
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
if ((buf.st_uid == geteuid() && buf.st_mode & (S_IRWXG | S_IRWXO)) ||
(buf.st_uid == 0 && buf.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO)))
{
ereport(loglevel,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("private key file \"%s\" has group or world access",
ssl_key_file),
errdetail("File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root.")));
return false;
}
#endif
return true;
}

View File

@ -92,7 +92,6 @@ extern ssize_t secure_read(Port *port, void *ptr, size_t len);
extern ssize_t secure_write(Port *port, void *ptr, size_t len);
extern ssize_t secure_raw_read(Port *port, void *ptr, size_t len);
extern ssize_t secure_raw_write(Port *port, const void *ptr, size_t len);
extern bool check_ssl_key_file_permissions(const char *ssl_key_file, bool isServerStart);
extern bool ssl_loaded_verify_locations;
@ -108,5 +107,7 @@ extern bool SSLPreferServerCiphers;
*/
extern int run_ssl_passphrase_command(const char *prompt, bool is_server_start,
char *buf, int size);
extern bool check_ssl_key_file_permissions(const char *ssl_key_file,
bool isServerStart);
#endif /* LIBPQ_H */