I just tried Jeff's patch and it does fix my problem. I wish I had remembered it earlier in the day yesterday! On 03/12/2014 06:22 AM, Jeff Layton wrote: > On Wed, 12 Mar 2014 05:21:13 -0400 > Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote: > >> On Mar 11, 2014, at 21:06, Jeffrey Layton <jlayton@xxxxxxxxxx> wrote: >> >>> On Tue, 11 Mar 2014 20:38:18 -0400 >>> Eric Paris <eparis@xxxxxxxxxx> wrote: >>> >>>> On Tue, 2014-03-11 at 18:00 -0400, Trond Myklebust wrote: >>>>> On Mar 11, 2014, at 17:27, Trond Myklebust >>>>> <trond.myklebust@xxxxxxxxxxxxxxx> wrote: >>>>> >>>>>> On Mar 11, 2014, at 17:11, Anna Schumaker >>>>>> <Anna.Schumaker@xxxxxxxxxx> wrote: >>>>>> >>>>>>> If the i_security field isn't set then >>>>>>> security_dentry_init_security() won't initialize some of the >>>>>>> values used by the security label. This causes my client to hit >>>>>>> a BUG_ON() while encoding a label of size -2128927414. >>>>>>> >>>>>>> I hit this bug while testing on a client without SELinux >>>>>>> installed. >>>>>>> >>>>>>> Signed-off-by: Anna Schumaker <anna.schumaker@xxxxxxxxxx> >>>>>>> --- >>>>>>> fs/nfs/nfs4proc.c | 3 +++ >>>>>>> 1 file changed, 3 insertions(+) >>>>>>> >>>>>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c >>>>>>> index b8cd560..994ccc2 100644 >>>>>>> --- a/fs/nfs/nfs4proc.c >>>>>>> +++ b/fs/nfs/nfs4proc.c >>>>>>> @@ -105,6 +105,9 @@ nfs4_label_init_security(struct inode *dir, >>>>>>> struct dentry *dentry, if (nfs_server_capable(dir, >>>>>>> NFS_CAP_SECURITY_LABEL) == 0) return NULL; >>>>>>> >>>>>>> + if (!dir->i_security) >>>>>>> + return NULL; >>>>>>> + >>>>>>> err = security_dentry_init_security(dentry, >>>>>>> sattr->ia_mode, &dentry->d_name, (void **)&label->label, >>>>>>> &label->len); if (err == 0) >>>>>> Hi Anna, >>>>>> >>>>>> This looks like a check that needs to be done by >>>>>> selinux_dentry_init_security() itself. The dir->i_security field >>>>>> is not something that NFS knows about. David, what needs to >>>>>> happen there when dentry->d_parent->i_security (a.k.a. dsec) is >>>>>> NULL? >>>>>> >>>>> Oh, wait. I missed the bit about ‘without SELinux installed’. So >>>>> the problem here is that you have a NFS client that does not have >>>>> SELinux set up, but running against a server that is advertising >>>>> NFSv4.2 with labeled NFS. Is that correct? >>>>> >>>>> It looks to me as if cap_dentry_init_security() will indeed trigger >>>>> this behaviour since it returns ‘0’ without doing anything to the >>>>> label. As far as I can see, the right thing to do there is to >>>>> return -EOPNOTSUPP, no? >>>> I feel like Jeff Layton was looking at the same thing, and came to the >>>> same conclusion... >>>> >>>> Jeff? >>>> >>> I posted a patch for this last week and James has merged it: >>> >>> [PATCH] security: have cap_dentry_init_security return error >>> >>> I didn't note it in the patch description but it fixes 4.2 when SELinux >>> is compiled in but disabled. >> Thanks! Then I expect no further action is needed on our part, and that the fix will come through the security tree? >> > FWIW, this is the bug that was causing the NFS server to spew messages > like this to the ring buffer when Anna was testing against my server at > Connectathon: > > [ 243.479524] SELinux: Context \xffffffdf is not valid (left unmapped). > > We may want to do a follow-on patch to clean up the struct nfs4_label > initializers since they're not really needed. But that should probably > wait until James merges this up to Linus. > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
