security: cap_inode_getsecctx returning garbage

We shouldn't be returning success from this function without also
filling in the return values ctx and ctxlen.

Note currently this doesn't appear to cause bugs since the only
inode_getsecctx caller I can find is fs/sysfs/inode.c, which only calls
this if security_inode_setsecurity succeeds.  Assuming
security_inode_setsecurity is set to cap_inode_setsecurity whenever
inode_getsecctx is set to cap_inode_getsecctx, this function can never
actually called.

So I noticed this only because the server labeled NFS patches add a real
caller.

Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/security/capability.c b/security/capability.c
index 1728d4e375db509c4e192e0e69fb1a0ee020bf49..83efc90b344d1ae96c2c9182444fd8ef82c71504 100644 (file)
--- a/security/capability.c
+++ b/security/capability.c
@@ -843,7 +843,7 @@ static int cap_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 
 static int cap_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
 {
-       return 0;
+       return -EOPNOTSUPP;
 }
 #ifdef CONFIG_KEYS
 static int cap_key_alloc(struct key *key, const struct cred *cred,