coda: Restrict coda messages to the initial user namespace

Remove the slight chance that uids and gids in coda messages will be
interpreted in the wrong user namespace.

- Only allow processes in the initial user namespace to open the coda
  character device to communicate with coda filesystems.
- Explicitly convert the uids in the coda header into the initial user
  namespace.
- In coda_vattr_to_attr make kuids and kgids from the initial user
  namespace uids and gids in struct coda_vattr that just came from
  userspace.
- In coda_iattr_to_vattr convert kuids and kgids into uids and gids
  in the intial user namespace and store them in struct coda_vattr for
  sending to coda userspace programs.

Nothing needs to be changed with mounts as coda does not support
being mounted in anything other than the initial user namespace.

Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2013-01-30 19:21:14 -08:00
parent 9fd973e085
commit d83f5901bc
4 changed files with 11 additions and 8 deletions

View file

@ -34,7 +34,7 @@ int venus_lookup(struct super_block *sb, struct CodaFid *fid,
const char *name, int length, int *type,
struct CodaFid *resfid);
int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
vuid_t uid);
kuid_t uid);
int venus_open(struct super_block *sb, struct CodaFid *fid, int flags,
struct file **f);
int venus_mkdir(struct super_block *sb, struct CodaFid *dirfid,