aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJosef Bacik <josef@redhat.com>2010-11-18 20:52:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-28 07:31:23 -0700
commita44ba30a832efbf9e48af31a5db8dc75f5a6663a (patch)
tree890d2322da9ba0b0f36112774f4dfe81628f1a5e
parent0db49efd46f6ad1db8ff26ccc4e4e2b6085180e1 (diff)
downloadlinux-linaro-stable-a44ba30a832efbf9e48af31a5db8dc75f5a6663a.tar.gz
fs: call security_d_instantiate in d_obtain_alias V2
commit 24ff6663ccfdaf088dfa7acae489cb11ed4f43c4 upstream. While trying to track down some NFS problems with BTRFS, I kept noticing I was getting -EACCESS for no apparent reason. Eric Paris and printk() helped me figure out that it was SELinux that was giving me grief, with the following denial type=AVC msg=audit(1290013638.413:95): avc: denied { 0x800000 } for pid=1772 comm="nfsd" name="" dev=sda1 ino=256 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file Turns out this is because in d_obtain_alias if we can't find an alias we create one and do all the normal instantiation stuff, but we don't do the security_d_instantiate. Usually we are protected from getting a hashed dentry that hasn't yet run security_d_instantiate() by the parent's i_mutex, but obviously this isn't an option there, so in order to deal with the case that a second thread comes in and finds our new dentry before we get to run security_d_instantiate(), we go ahead and call it if we find a dentry already. Eric assures me that this is ok as the code checks to see if the dentry has been initialized already so calling security_d_instantiate() against the same dentry multiple times is ok. With this patch I'm no longer getting errant -EACCESS values. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/dcache.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 953173a293a9..b6f6abb0cd63 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1176,9 +1176,12 @@ struct dentry *d_obtain_alias(struct inode *inode)
spin_unlock(&tmp->d_lock);
spin_unlock(&dcache_lock);
+ security_d_instantiate(tmp, inode);
return tmp;
out_iput:
+ if (res && !IS_ERR(res))
+ security_d_instantiate(res, inode);
iput(inode);
return res;
}