database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Add default roles for file/program access

Browse Source 
This patch adds new default roles named 'pg_read_server_files',
'pg_write_server_files', 'pg_execute_server_program' which
allow an administrator to GRANT to a non-superuser role the ability to
access server-side files or run programs through PostgreSQL (as the user
the database is running as).  Having one of these roles allows a
non-superuser to use server-side COPY to read, write, or with a program,
and to use file_fdw (if installed by a superuser and GRANT'd USAGE on
it) to read from files or run a program.

The existing misc file functions are also changed to allow a user with
the 'pg_read_server_files' default role to read any files on the
filesystem, matching the privileges given to that role through COPY and
file_fdw from above.

Reviewed-By: Michael Paquier
Discussion: https://postgr.es/m/20171231191939.GR2416%40tamriel.snowman.net
This commit is contained in:
Stephen Frost
2018-04-06 14:47:10 -04:00
parent e79350fef2
commit 0fdc8495bf
9 changed files with 145 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
src/backend/commands/copy.c
View File

@ -23,6 +23,8 @@
#include "access/sysattr.h"
#include "access/xact.h"
#include "access/xlog.h"
#include "catalog/dependency.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_type.h"
#include "commands/copy.h"
#include "commands/defrem.h"
@ -769,8 +771,8 @@ CopyLoadRawBuf(CopyState cstate)
* input/output stream. The latter could be either stdin/stdout or a
* socket, depending on whether we're running under Postmaster control.
*
* Do not allow a Postgres user without superuser privilege to read from
* or write to a file.
* Do not allow a Postgres user without the 'pg_access_server_files' role to
* read from or write to a file.
*
* Do not allow the copy if user doesn't have proper permission to access
* the table or the specifically requested columns.
@ -787,21 +789,37 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
Oid relid;
RawStmt *query = NULL;
/* Disallow COPY to/from file or program except to superusers. */
if (!pipe && !superuser())
/*
* Disallow COPY to/from file or program except to users with the
* appropriate role.
*/
if (!pipe)
{
if (stmt->is_program)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from an external program"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
{
if (!is_member_of_role(GetUserId(), DEFAULT_ROLE_EXECUTE_SERVER_PROGRAM))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or a member of the pg_execute_server_program role to COPY to or from an external program"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
else
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from a file"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
{
if (is_from && !is_member_of_role(GetUserId(), DEFAULT_ROLE_READ_SERVER_FILES))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or a member of the pg_read_server_files role to COPY from a file"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
if (!is_from && !is_member_of_role(GetUserId(), DEFAULT_ROLE_WRITE_SERVER_FILES))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser or a member of the pg_write_server_files role to COPY to a file"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
}
if (stmt->relation)

16
src/backend/utils/adt/genfile.c
View File

@ -22,6 +22,7 @@
#include "access/htup_details.h"
#include "access/xlog_internal.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
@ -45,6 +46,12 @@ typedef struct
*
* Filename may be absolute or relative to the DataDir, but we only allow
* absolute paths that match DataDir or Log_directory.
*
* This does a privilege check against the 'pg_read_server_files' role, so
* this function is really only appropriate for callers who are only checking
* 'read' access. Do not use this function if you are looking for a check
* for 'write' or 'program' access without updating it to access the type
* of check as an argument and checking the appropriate role membership.
*/
static char *
convert_and_check_filename(text *arg)
@ -54,6 +61,15 @@ convert_and_check_filename(text *arg)
filename = text_to_cstring(arg);
canonicalize_path(filename); /* filename can change length here */
/*
* Members of the 'pg_read_server_files' role are allowed to access any
* files on the server as the PG user, so no need to do any further checks
* here.
*/
if (is_member_of_role(GetUserId(), DEFAULT_ROLE_READ_SERVER_FILES))
return filename;
/* User isn't a member of the default role, so check if it's allowable */
if (is_absolute_path(filename))
{
/* Disallow '/a/b/data/..' */

6
src/include/catalog/pg_authid.h
View File

@ -108,6 +108,12 @@ DATA(insert OID = 3375 ( "pg_read_all_stats" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_READ_ALL_STATS 3375
DATA(insert OID = 3377 ( "pg_stat_scan_tables" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_STAT_SCAN_TABLES 3377
DATA(insert OID = 4569 ( "pg_read_server_files" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_READ_SERVER_FILES 4569
DATA(insert OID = 4570 ( "pg_write_server_files" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_WRITE_SERVER_FILES 4570
DATA(insert OID = 4571 ( "pg_execute_server_program" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_EXECUTE_SERVER_PROGRAM 4571
DATA(insert OID = 4200 ( "pg_signal_backend" f t f f f f f -1 _null_ _null_));
#define DEFAULT_ROLE_SIGNAL_BACKENDID 4200