Thread: BUG #15371: a user who not a member of pg_read_server_files role cancreate a new user into pg_read_server_files
BUG #15371: a user who not a member of pg_read_server_files role cancreate a new user into pg_read_server_files
From
PG Bug reporting form
Date:
The following bug has been logged on the website: Bug reference: 15371 Logged by: zhou xiaowei Email address: 110876189@qq.com PostgreSQL version: 11beta2 Operating system: linux Description: my test step: 1,execute "CREATE USER mytestuser WITH PASSWORD '12345678' CREATEDB CREATEROLE;" use a supper user; 2,use mytestuser to login, and then execute "copy mytestuser_t from '/data/dev_zxw/PGcore/src/copy1.sql';". I got "ERROR: must be superuser or a member of the pg_read_server_files role to COPY from a file", this result is OK. contine to execute "create user mytestuser1 with password '12345678' in role pg_read_server_files;". I got a success result ,which is unexpected. 3, use mytestuser1 login again, I execute "copy mytestuser_t1 from '/data/dev_zxw/PGcore/src/copy1.sql';" successfully. this result is unexpected. the details: [ src]$ psql postgres -p54xx psql (11beta2) Type "help" for help. postgres=# CREATE USER mytestuser WITH PASSWORD '12345678' CREATEDB CREATEROLE; CREATE ROLE postgres=# \q [ src]$ psql postgres -h10.21.x.x -p54xx -Umytestuser Password for user mytestuser: psql (11beta2) Type "help" for help. postgres=> create table mytestuser_t(f int,f1 int); CREATE TABLE postgres=> copy mytestuser_t from '/data/dev_zxw/PGcore/src/copy1.sql'; ERROR: must be superuser or a member of the pg_read_server_files role to COPY from a file HINT: Anyone can COPY to stdout or from stdin. psql's \copy command also works for anyone. postgres=> create user mytestuser1 with password '12345678' in role pg_read_server_files; CREATE ROLE postgres=> \q [ src]$ psql postgres -h10.21.x.x -p54xx -Umytestuser1 Password for user mytestuser1: psql (11beta2) Type "help" for help. postgres=> create table mytestuser_t1(f int,f1 int); CREATE TABLE postgres=> copy mytestuser_t1 from '/data/dev_zxw/PGcore/src/copy1.sql'; COPY 1 postgres=> postgres=> select * from mytestuser_t1; f | f1 ---+---- 2 | 4 (1 row) see the code src/backend/commands/user.c, the check privillige code is : static void AddRoleMems(const char *rolename, Oid roleid, List *memberSpecs, List *memberIds, Oid grantorId, bool admin_opt) { else { if (!have_createrole_privilege() && !is_admin_of_role(grantorId, roleid)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("must have admin option on role \"%s\"", rolename))); } I think the line "if (!have_createrole_privilege() && !is_admin_of_role(grantorId, roleid))" should been modifed to "if (!have_createrole_privilege() || !is_admin_of_role(grantorId, roleid))" . am I right or not? Thanks!
Re: BUG #15371: a user who not a member of pg_read_server_files rolecan create a new user into pg_read_server_files
From
"David G. Johnston"
Date:
On Saturday, September 8, 2018, PG Bug reporting form <noreply@postgresql.org> wrote:
see the code src/backend/commands/user.c, the check privillige code is :
static void
AddRoleMems(const char *rolename, Oid roleid,
List *memberSpecs, List *memberIds,
Oid grantorId, bool admin_opt)
{
else
{
if (!have_createrole_privilege() &&
!is_admin_of_role(grantorId, roleid))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must have admin option on role \"%s\"",
rolename)));
}
I think the line "if (!have_createrole_privilege() &&
!is_admin_of_role(grantorId, roleid))" should been modifed to "if
(!have_createrole_privilege() || !is_admin_of_role(grantorId, roleid))" .
Security code would ideally be written so not erroring requires an actual matched condition while leaving the default to be an error. So, I think, the && is ok, remove both negations, put a commented no-op there, and move the error to an else block.
Whether that is sufficient for this bug I do not know, but it would be a more secure format.
David J.
Re: BUG #15371: a user who not a member of pg_read_server_files rolecan create a new user into pg_read_server_files
From
"David G. Johnston"
Date:
On Saturday, September 8, 2018, PG Bug reporting form <noreply@postgresql.org> wrote:
1,execute "CREATE USER mytestuser WITH PASSWORD '12345678' CREATEDB
CREATEROLE;" use a supper user;
So, reading the create role docs this seems to be working as designed.
“ Be careful with the
CREATEROLE
privilege. There is no concept of inheritance for the privileges of a CREATEROLE
-role. That means that even if a role does not have a certain privilege but is allowed to create other roles, it can easily create another role with different privileges than its own (except for creating roles with superuser privileges)“David J.