On 21 Feb 2011, at 09:36, Simon Slavin wrote:
> On 21 Feb 2011, at 9:35am, Philip Graham Willoughby wrote:
>
>> On 20 Feb 2011, at 16:18, thilo wrote:
>>
>>> My DB is owned by a different user (www) and I as root insert some data.
>> ...
>>> Are there any suggestions on how to make this workable?
>>
>> Don't do that. Unless you can guarantee that no malicious user has been able
>> to alter your database it isn't safe to interact with it as root if you're
>> using a version of the sqlite3 shell that has the .load built-in. Use su or
>> sudo to become www and interact with your data as the owning user.
>
> Would it be feasible to copy whatever protection is on the database file to
> any temporary files like journal files ?
On systems with traditional unix permissions if you have authority to create a
file in a directory you also have authority to set the created file's
permissions. You can also change the group of the file to any group of which
you are a member. Conceptually, the relevant VFSs would need to do something
like this when creating subsidiary files:
// Allow us to set whatever file mode we want
mode_t oldmode = umask(0);
struct stat dbstat;
// Retrieve database permissions etc
fstat(dbfh, &dbstat);
// Create file with the right permissions if necessary
int newfd = open(…,…|O_EXCL|O_CREAT,dbstat.st_mode);
// Match the group id - should usually work
if (fchown(newfd,-1,dbstat.st_gid))
{
// Could not change gid to match db
// log warning?
}
// Match the user id - should usually fail
if (fchown(newfd,dbstat.st_uid,-1))
{
// Could not change uid to match db
// log warning?
}
// restore umask
umask(oldmode);
For me, the mode-matching is definitely worth it - if you have a group-writable
database you almost certainly want a group-writable log. Similarly the
gid-matching code is worthwhile for the same reason.
The uid-matching code is only usable by root or processes given that privilege
by some other mechanism and is therefore less worthwhile.
Best Regards,
Phil Willoughby
--
Managing Director, StrawberryCat Limited
StrawberryCat Limited is registered in England and Wales with Company No.
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