path: root/fs
diff options
authorJosef Bacik <josef@redhat.com>2010-11-18 20:52:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-27 11:36:38 -0700
commitc9da0558d0b82ac448d12af27c6f743b86aecf66 (patch)
tree360dfbf4d483df5a8026cc06a42f1c2f1ffbd069 /fs
parent59887b744b4b8f3a68d31b2b29a4084bbe3a6e07 (diff)
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>
Diffstat (limited to 'fs')
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index a39fe47c466..1baddc1cec4 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1612,10 +1612,13 @@ struct dentry *d_obtain_alias(struct inode *inode)
__bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
+ security_d_instantiate(tmp, inode);
return tmp;
+ if (res && !IS_ERR(res))
+ security_d_instantiate(res, inode);
return res;