On Tue, 4 Jan 2011 16:19:26 -0600 Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote: > On Tue, Jan 4, 2011 at 4:10 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > On Tue, 4 Jan 2011 14:27:45 -0600 > > Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote: > > > >> On Tue, Jan 4, 2011 at 2:09 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > >> > On Tue, 4 Jan 2011 13:51:41 -0600 > >> > Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote: > >> > > >> >> On Tue, Jan 4, 2011 at 1:31 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > >> >> > On Tue, 4 Jan 2011 13:20:38 -0600 > >> >> > Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote: > >> >> > > >> >> >> On Tue, Jan 4, 2011 at 1:11 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > >> >> >> > On Mon, 6 Dec 2010 14:56:46 -0600 > >> >> >> > shirishpargaonkar@xxxxxxxxx wrote: > >> >> >> > > >> >> >> >> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> > >> >> >> >> > >> >> >> >> > >> >> >> >> If a DACL has entries for ACEs for SID Everyone and Authenticated Users, > >> >> >> >> factor in mask in respective entries during calculation of permissions > >> >> >> >> for all three, user, group, and other. > >> >> >> >> > >> >> >> >> http://technet.microsoft.com/en-us/library/bb463216.aspx > >> >> >> >> > >> >> >> >> > >> >> >> >> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> > >> >> >> >> --- > >> >> >> >> fs/cifs/cifsacl.c | 13 +++++++++++-- > >> >> >> >> 1 files changed, 11 insertions(+), 2 deletions(-) > >> >> >> >> > >> >> >> >> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c > >> >> >> >> index c6ebea0..a520091 100644 > >> >> >> >> --- a/fs/cifs/cifsacl.c > >> >> >> >> +++ b/fs/cifs/cifsacl.c > >> >> >> >> @@ -43,9 +43,12 @@ static struct cifs_wksid wksidarr[NUM_WK_SIDS] = { > >> >> >> >> ; > >> >> >> >> > >> >> >> >> > >> >> >> >> -/* security id for everyone */ > >> >> >> >> +/* security id for everyone/world system group */ > >> >> >> >> static const struct cifs_sid sid_everyone = { > >> >> >> >> 1, 1, {0, 0, 0, 0, 0, 1}, {0} }; > >> >> >> >> +/* security id for Authenticated Users system group */ > >> >> >> >> +static const struct cifs_sid sid_authusers = { > >> >> >> >> + 1, 1, {0, 0, 0, 0, 0, 5}, {11} }; > >> >> >> >> /* group users */ > >> >> >> >> static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} }; > >> >> >> >> > >> >> >> >> @@ -367,7 +370,7 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, > >> >> >> >> if (num_aces > 0) { > >> >> >> >> umode_t user_mask = S_IRWXU; > >> >> >> >> umode_t group_mask = S_IRWXG; > >> >> >> >> - umode_t other_mask = S_IRWXO; > >> >> >> >> + umode_t other_mask = S_IRWXU | S_IRWXG | S_IRWXO; > >> >> >> >> > >> >> >> >> ppace = kmalloc(num_aces * sizeof(struct cifs_ace *), > >> >> >> >> GFP_KERNEL); > >> >> >> >> @@ -392,6 +395,12 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, > >> >> >> >> ppace[i]->type, > >> >> >> >> &fattr->cf_mode, > >> >> >> >> &other_mask); > >> >> >> >> + if (compare_sids(&(ppace[i]->sid), &sid_authusers)) > >> >> >> >> + access_flags_to_mode(ppace[i]->access_req, > >> >> >> >> + ppace[i]->type, > >> >> >> >> + &fattr->cf_mode, > >> >> >> >> + &other_mask); > >> >> >> >> + > >> >> >> >> > >> >> >> >> /* memcpy((void *)(&(cifscred->aces[i])), > >> >> >> >> (void *)ppace[i], > >> >> >> > > >> >> >> > This looks like a harmless change... > >> >> >> > > >> >> >> > Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> > >> >> >> > > >> >> >> > >> >> >> Jeff, Thanks. > >> >> >> > >> >> >> > I have real doubts however about the owner/group parts of the cifsacl > >> >> >> > scheme. It sets the user and group mode bits without setting the user > >> >> >> > and group owners to meaningful values. So, those permissions have no > >> >> >> > basis in reality. > >> >> >> > >> >> >> With the sid to uid and gid mapping code using winbind in the works, > >> >> >> would that address these concerns? > >> >> >> > >> >> > > >> >> > Yes, that would help some. > >> >> > > >> >> > That would give you the ability to present permissions that have some > >> >> > basis in reality. You'll still have to figure out what to do when you > >> >> > get a SID that can't be mapped for some reason. > >> >> > >> >> If we are using winbind, I do not see how this can happen. > >> >> A SID perhaps could not be looked up but winbind, when asked, > >> >> can/will always map a Owner SID to an uid and Group SID to a gid. > >> >> > >> > > >> > Ahh ok. Good to know. Still, we need a meaningful owner to set it to > >> > when the upcall fails. For instance, if the upcall isn't set up at > >> > all... > >> > > >> > >> I think at least two things can go against, either upcall is not setup at all > >> so an upcall fails or we run out of idmap range as specified in smb.conf > >> file for either uid or gid or both and so upcall fails. > >> > > > > Yep. The reason for the failure doesn't matter much. What matters is > > what you do if it does. You'll need to set the uid or gid to something. > > > > What will you set it to? > > > > I think it should default to 0 (superuser). > That sounds a little dangerous. What if the mode bits indicate setuid? rpc.idmapd generally maps users to "nobody" if no mapping can be found. Something like that might be a safer default. It should probably be a tunable setting too. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
